// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
 */

#include <linux/acpi.h>
#include <linux/mman.h>
#include <linux/kvm_host.h>
#include <linux/io.h>
#include <linux/hugetlb.h>
#include <linux/sched/signal.h>
#include <trace/events/kvm.h>
#include <asm/acpi.h>
#include <asm/pgalloc.h>
#include <asm/cacheflush.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_mmu.h>
#include <asm/kvm_pgtable.h>
#include <asm/kvm_pkvm.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
#include <asm/virt.h>

#include "trace.h"

static struct kvm_pgtable *hyp_pgtable;
static DEFINE_MUTEX(kvm_hyp_pgd_mutex);

static unsigned long __ro_after_init hyp_idmap_start;
static unsigned long __ro_after_init hyp_idmap_end;
static phys_addr_t __ro_after_init hyp_idmap_vector;

u32 __ro_after_init __hyp_va_bits;

static unsigned long __ro_after_init io_map_base;

#define KVM_PGT_FN(fn)          (!is_protected_kvm_enabled() ? fn : p ## fn)

static phys_addr_t __stage2_range_addr_end(phys_addr_t addr, phys_addr_t end,
                                           phys_addr_t size)
{
        phys_addr_t boundary = ALIGN_DOWN(addr + size, size);

        return (boundary - 1 < end - 1) ? boundary : end;
}

static phys_addr_t stage2_range_addr_end(phys_addr_t addr, phys_addr_t end)
{
        phys_addr_t size = kvm_granule_size(KVM_PGTABLE_MIN_BLOCK_LEVEL);

        return __stage2_range_addr_end(addr, end, size);
}

/*
 * Release kvm_mmu_lock periodically if the memory region is large. Otherwise,
 * we may see kernel panics with CONFIG_DETECT_HUNG_TASK,
 * CONFIG_LOCKUP_DETECTOR, CONFIG_LOCKDEP. Additionally, holding the lock too
 * long will also starve other vCPUs. We have to also make sure that the page
 * tables are not freed while we released the lock.
 */
static int stage2_apply_range(struct kvm_s2_mmu *mmu, phys_addr_t addr,
                              phys_addr_t end,
                              int (*fn)(struct kvm_pgtable *, u64, u64),
                              bool resched)
{
        struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu);
        int ret;
        u64 next;

        do {
                struct kvm_pgtable *pgt = mmu->pgt;
                if (!pgt)
                        return -EINVAL;

                next = stage2_range_addr_end(addr, end);
                ret = fn(pgt, addr, next - addr);
                if (ret)
                        break;

                if (resched && next != end)
                        cond_resched_rwlock_write(&kvm->mmu_lock);
        } while (addr = next, addr != end);

        return ret;
}

#define stage2_apply_range_resched(mmu, addr, end, fn)                  \
        stage2_apply_range(mmu, addr, end, fn, true)

/*
 * Get the maximum number of page-tables pages needed to split a range
 * of blocks into PAGE_SIZE PTEs. It assumes the range is already
 * mapped at level 2, or at level 1 if allowed.
 */
static int kvm_mmu_split_nr_page_tables(u64 range)
{
        int n = 0;

        if (KVM_PGTABLE_MIN_BLOCK_LEVEL < 2)
                n += DIV_ROUND_UP(range, PUD_SIZE);
        n += DIV_ROUND_UP(range, PMD_SIZE);
        return n;
}

static bool need_split_memcache_topup_or_resched(struct kvm *kvm)
{
        struct kvm_mmu_memory_cache *cache;
        u64 chunk_size, min;

        if (need_resched() || rwlock_needbreak(&kvm->mmu_lock))
                return true;

        chunk_size = kvm->arch.mmu.split_page_chunk_size;
        min = kvm_mmu_split_nr_page_tables(chunk_size);
        cache = &kvm->arch.mmu.split_page_cache;
        return kvm_mmu_memory_cache_nr_free_objects(cache) < min;
}

static int kvm_mmu_split_huge_pages(struct kvm *kvm, phys_addr_t addr,
                                    phys_addr_t end)
{
        struct kvm_mmu_memory_cache *cache;
        struct kvm_pgtable *pgt;
        int ret, cache_capacity;
        u64 next, chunk_size;

        lockdep_assert_held_write(&kvm->mmu_lock);

        chunk_size = kvm->arch.mmu.split_page_chunk_size;
        cache_capacity = kvm_mmu_split_nr_page_tables(chunk_size);

        if (chunk_size == 0)
                return 0;

        cache = &kvm->arch.mmu.split_page_cache;

        do {
                if (need_split_memcache_topup_or_resched(kvm)) {
                        write_unlock(&kvm->mmu_lock);
                        cond_resched();
                        /* Eager page splitting is best-effort. */
                        ret = __kvm_mmu_topup_memory_cache(cache,
                                                           cache_capacity,
                                                           cache_capacity);
                        write_lock(&kvm->mmu_lock);
                        if (ret)
                                break;
                }

                pgt = kvm->arch.mmu.pgt;
                if (!pgt)
                        return -EINVAL;

                next = __stage2_range_addr_end(addr, end, chunk_size);
                ret = KVM_PGT_FN(kvm_pgtable_stage2_split)(pgt, addr, next - addr, cache);
                if (ret)
                        break;
        } while (addr = next, addr != end);

        return ret;
}

static bool memslot_is_logging(struct kvm_memory_slot *memslot)
{
        return memslot->dirty_bitmap && !(memslot->flags & KVM_MEM_READONLY);
}

/**
 * kvm_arch_flush_remote_tlbs() - flush all VM TLB entries for v7/8
 * @kvm:        pointer to kvm structure.
 *
 * Interface to HYP function to flush all VM TLB entries
 */
int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
{
        if (is_protected_kvm_enabled())
                kvm_call_hyp_nvhe(__pkvm_tlb_flush_vmid, kvm->arch.pkvm.handle);
        else
                kvm_call_hyp(__kvm_tlb_flush_vmid, &kvm->arch.mmu);
        return 0;
}

int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm,
                                      gfn_t gfn, u64 nr_pages)
{
        u64 size = nr_pages << PAGE_SHIFT;
        u64 addr = gfn << PAGE_SHIFT;

        if (is_protected_kvm_enabled())
                kvm_call_hyp_nvhe(__pkvm_tlb_flush_vmid, kvm->arch.pkvm.handle);
        else
                kvm_tlb_flush_vmid_range(&kvm->arch.mmu, addr, size);
        return 0;
}

static void *stage2_memcache_zalloc_page(void *arg)
{
        struct kvm_mmu_memory_cache *mc = arg;
        void *virt;

        /* Allocated with __GFP_ZERO, so no need to zero */
        virt = kvm_mmu_memory_cache_alloc(mc);
        if (virt)
                kvm_account_pgtable_pages(virt, 1);
        return virt;
}

static void *kvm_host_zalloc_pages_exact(size_t size)
{
        return alloc_pages_exact(size, GFP_KERNEL_ACCOUNT | __GFP_ZERO);
}

static void *kvm_s2_zalloc_pages_exact(size_t size)
{
        void *virt = kvm_host_zalloc_pages_exact(size);

        if (virt)
                kvm_account_pgtable_pages(virt, (size >> PAGE_SHIFT));
        return virt;
}

static void kvm_s2_free_pages_exact(void *virt, size_t size)
{
        kvm_account_pgtable_pages(virt, -(size >> PAGE_SHIFT));
        free_pages_exact(virt, size);
}

static struct kvm_pgtable_mm_ops kvm_s2_mm_ops;

static void stage2_free_unlinked_table_rcu_cb(struct rcu_head *head)
{
        struct page *page = container_of(head, struct page, rcu_head);
        void *pgtable = page_to_virt(page);
        s8 level = page_private(page);

        KVM_PGT_FN(kvm_pgtable_stage2_free_unlinked)(&kvm_s2_mm_ops, pgtable, level);
}

static void stage2_free_unlinked_table(void *addr, s8 level)
{
        struct page *page = virt_to_page(addr);

        set_page_private(page, (unsigned long)level);
        call_rcu(&page->rcu_head, stage2_free_unlinked_table_rcu_cb);
}

static void kvm_host_get_page(void *addr)
{
        get_page(virt_to_page(addr));
}

static void kvm_host_put_page(void *addr)
{
        put_page(virt_to_page(addr));
}

static void kvm_s2_put_page(void *addr)
{
        struct page *p = virt_to_page(addr);
        /* Dropping last refcount, the page will be freed */
        if (page_count(p) == 1)
                kvm_account_pgtable_pages(addr, -1);
        put_page(p);
}

static int kvm_host_page_count(void *addr)
{
        return page_count(virt_to_page(addr));
}

static phys_addr_t kvm_host_pa(void *addr)
{
        return __pa(addr);
}

static void *kvm_host_va(phys_addr_t phys)
{
        return __va(phys);
}

static void clean_dcache_guest_page(void *va, size_t size)
{
        __clean_dcache_guest_page(va, size);
}

static void invalidate_icache_guest_page(void *va, size_t size)
{
        __invalidate_icache_guest_page(va, size);
}

/*
 * Unmapping vs dcache management:
 *
 * If a guest maps certain memory pages as uncached, all writes will
 * bypass the data cache and go directly to RAM.  However, the CPUs
 * can still speculate reads (not writes) and fill cache lines with
 * data.
 *
 * Those cache lines will be *clean* cache lines though, so a
 * clean+invalidate operation is equivalent to an invalidate
 * operation, because no cache lines are marked dirty.
 *
 * Those clean cache lines could be filled prior to an uncached write
 * by the guest, and the cache coherent IO subsystem would therefore
 * end up writing old data to disk.
 *
 * This is why right after unmapping a page/section and invalidating
 * the corresponding TLBs, we flush to make sure the IO subsystem will
 * never hit in the cache.
 *
 * This is all avoided on systems that have ARM64_HAS_STAGE2_FWB, as
 * we then fully enforce cacheability of RAM, no matter what the guest
 * does.
 */
/**
 * __unmap_stage2_range -- Clear stage2 page table entries to unmap a range
 * @mmu:   The KVM stage-2 MMU pointer
 * @start: The intermediate physical base address of the range to unmap
 * @size:  The size of the area to unmap
 * @may_block: Whether or not we are permitted to block
 *
 * Clear a range of stage-2 mappings, lowering the various ref-counts.  Must
 * be called while holding mmu_lock (unless for freeing the stage2 pgd before
 * destroying the VM), otherwise another faulting VCPU may come in and mess
 * with things behind our backs.
 */
static void __unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size,
                                 bool may_block)
{
        struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu);
        phys_addr_t end = start + size;

        lockdep_assert_held_write(&kvm->mmu_lock);
        WARN_ON(size & ~PAGE_MASK);
        WARN_ON(stage2_apply_range(mmu, start, end, KVM_PGT_FN(kvm_pgtable_stage2_unmap),
                                   may_block));
}

void kvm_stage2_unmap_range(struct kvm_s2_mmu *mmu, phys_addr_t start,
                            u64 size, bool may_block)
{
        if (kvm_vm_is_protected(kvm_s2_mmu_to_kvm(mmu)))
                return;

        __unmap_stage2_range(mmu, start, size, may_block);
}

void kvm_stage2_flush_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, phys_addr_t end)
{
        stage2_apply_range_resched(mmu, addr, end, KVM_PGT_FN(kvm_pgtable_stage2_flush));
}

static void stage2_flush_memslot(struct kvm *kvm,
                                 struct kvm_memory_slot *memslot)
{
        phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
        phys_addr_t end = addr + PAGE_SIZE * memslot->npages;

        kvm_stage2_flush_range(&kvm->arch.mmu, addr, end);
}

/**
 * stage2_flush_vm - Invalidate cache for pages mapped in stage 2
 * @kvm: The struct kvm pointer
 *
 * Go through the stage 2 page tables and invalidate any cache lines
 * backing memory already mapped to the VM.
 */
static void stage2_flush_vm(struct kvm *kvm)
{
        struct kvm_memslots *slots;
        struct kvm_memory_slot *memslot;
        int idx, bkt;

        idx = srcu_read_lock(&kvm->srcu);
        write_lock(&kvm->mmu_lock);

        slots = kvm_memslots(kvm);
        kvm_for_each_memslot(memslot, bkt, slots)
                stage2_flush_memslot(kvm, memslot);

        kvm_nested_s2_flush(kvm);

        write_unlock(&kvm->mmu_lock);
        srcu_read_unlock(&kvm->srcu, idx);
}

/**
 * free_hyp_pgds - free Hyp-mode page tables
 */
void __init free_hyp_pgds(void)
{
        mutex_lock(&kvm_hyp_pgd_mutex);
        if (hyp_pgtable) {
                kvm_pgtable_hyp_destroy(hyp_pgtable);
                kfree(hyp_pgtable);
                hyp_pgtable = NULL;
        }
        mutex_unlock(&kvm_hyp_pgd_mutex);
}

static bool kvm_host_owns_hyp_mappings(void)
{
        if (is_kernel_in_hyp_mode())
                return false;

        if (static_branch_likely(&kvm_protected_mode_initialized))
                return false;

        /*
         * This can happen at boot time when __create_hyp_mappings() is called
         * after the hyp protection has been enabled, but the static key has
         * not been flipped yet.
         */
        if (!hyp_pgtable && is_protected_kvm_enabled())
                return false;

        WARN_ON(!hyp_pgtable);

        return true;
}

int __create_hyp_mappings(unsigned long start, unsigned long size,
                          unsigned long phys, enum kvm_pgtable_prot prot)
{
        int err;

        if (WARN_ON(!kvm_host_owns_hyp_mappings()))
                return -EINVAL;

        mutex_lock(&kvm_hyp_pgd_mutex);
        err = kvm_pgtable_hyp_map(hyp_pgtable, start, size, phys, prot);
        mutex_unlock(&kvm_hyp_pgd_mutex);

        return err;
}

static phys_addr_t kvm_kaddr_to_phys(void *kaddr)
{
        if (!is_vmalloc_addr(kaddr)) {
                BUG_ON(!virt_addr_valid(kaddr));
                return __pa(kaddr);
        } else {
                return page_to_phys(vmalloc_to_page(kaddr)) +
                       offset_in_page(kaddr);
        }
}

struct hyp_shared_pfn {
        u64 pfn;
        int count;
        struct rb_node node;
};

static DEFINE_MUTEX(hyp_shared_pfns_lock);
static struct rb_root hyp_shared_pfns = RB_ROOT;

static struct hyp_shared_pfn *find_shared_pfn(u64 pfn, struct rb_node ***node,
                                              struct rb_node **parent)
{
        struct hyp_shared_pfn *this;

        *node = &hyp_shared_pfns.rb_node;
        *parent = NULL;
        while (**node) {
                this = container_of(**node, struct hyp_shared_pfn, node);
                *parent = **node;
                if (this->pfn < pfn)
                        *node = &((**node)->rb_left);
                else if (this->pfn > pfn)
                        *node = &((**node)->rb_right);
                else
                        return this;
        }

        return NULL;
}

static int share_pfn_hyp(u64 pfn)
{
        struct rb_node **node, *parent;
        struct hyp_shared_pfn *this;
        int ret = 0;

        mutex_lock(&hyp_shared_pfns_lock);
        this = find_shared_pfn(pfn, &node, &parent);
        if (this) {
                this->count++;
                goto unlock;
        }

        this = kzalloc_obj(*this);
        if (!this) {
                ret = -ENOMEM;
                goto unlock;
        }

        this->pfn = pfn;
        this->count = 1;
        rb_link_node(&this->node, parent, node);
        rb_insert_color(&this->node, &hyp_shared_pfns);
        ret = kvm_call_hyp_nvhe(__pkvm_host_share_hyp, pfn);
        if (ret) {
                rb_erase(&this->node, &hyp_shared_pfns);
                kfree(this);
        }
unlock:
        mutex_unlock(&hyp_shared_pfns_lock);

        return ret;
}

static int unshare_pfn_hyp(u64 pfn)
{
        struct rb_node **node, *parent;
        struct hyp_shared_pfn *this;
        int ret = 0;

        mutex_lock(&hyp_shared_pfns_lock);
        this = find_shared_pfn(pfn, &node, &parent);
        if (WARN_ON(!this)) {
                ret = -ENOENT;
                goto unlock;
        }

        if (this->count > 1) {
                this->count--;
                goto unlock;
        }

        ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_hyp, pfn);
        if (ret)
                goto unlock;

        rb_erase(&this->node, &hyp_shared_pfns);
        kfree(this);
unlock:
        mutex_unlock(&hyp_shared_pfns_lock);

        return ret;
}

int kvm_share_hyp(void *from, void *to)
{
        phys_addr_t start, end, cur;
        int ret = 0;
        u64 pfn;

        if (is_kernel_in_hyp_mode())
                return 0;

        /*
         * The share hcall maps things in the 'fixed-offset' region of the hyp
         * VA space, so we can only share physically contiguous data-structures
         * for now.
         */
        if (is_vmalloc_or_module_addr(from) || is_vmalloc_or_module_addr(to))
                return -EINVAL;

        if (kvm_host_owns_hyp_mappings())
                return create_hyp_mappings(from, to, PAGE_HYP);

        start = ALIGN_DOWN(__pa(from), PAGE_SIZE);
        end = PAGE_ALIGN(__pa(to));
        for (cur = start; cur < end; cur += PAGE_SIZE) {
                pfn = __phys_to_pfn(cur);
                ret = share_pfn_hyp(pfn);
                if (ret)
                        break;
        }

        if (!ret)
                return 0;

        /*
         * Roll back the pages shared by this call. A failed unshare leaks
         * the page (it stays shared with the hypervisor and is no longer
         * reusable for pKVM) but breaks no isolation guarantee, so warn and
         * continue. Not expected in practice.
         */
        for (end = cur, cur = start; cur < end; cur += PAGE_SIZE) {
                pfn = __phys_to_pfn(cur);
                WARN_ON(unshare_pfn_hyp(pfn));
        }

        return ret;
}

void kvm_unshare_hyp(void *from, void *to)
{
        phys_addr_t start, end, cur;
        u64 pfn;

        if (is_kernel_in_hyp_mode() || kvm_host_owns_hyp_mappings() || !from)
                return;

        start = ALIGN_DOWN(__pa(from), PAGE_SIZE);
        end = PAGE_ALIGN(__pa(to));
        for (cur = start; cur < end; cur += PAGE_SIZE) {
                pfn = __phys_to_pfn(cur);
                /*
                 * A failed unshare leaks the page: it stays shared with the
                 * hypervisor and is no longer reusable for pKVM. No isolation
                 * guarantee is broken, and this is not expected in practice.
                 */
                WARN_ON(unshare_pfn_hyp(pfn));
        }
}

/**
 * create_hyp_mappings - duplicate a kernel virtual address range in Hyp mode
 * @from:       The virtual kernel start address of the range
 * @to:         The virtual kernel end address of the range (exclusive)
 * @prot:       The protection to be applied to this range
 *
 * The same virtual address as the kernel virtual address is also used
 * in Hyp-mode mapping (modulo HYP_PAGE_OFFSET) to the same underlying
 * physical pages.
 */
int create_hyp_mappings(void *from, void *to, enum kvm_pgtable_prot prot)
{
        phys_addr_t phys_addr;
        unsigned long virt_addr;
        unsigned long start = kern_hyp_va((unsigned long)from);
        unsigned long end = kern_hyp_va((unsigned long)to);

        if (is_kernel_in_hyp_mode())
                return 0;

        if (!kvm_host_owns_hyp_mappings())
                return -EPERM;

        start = start & PAGE_MASK;
        end = PAGE_ALIGN(end);

        for (virt_addr = start; virt_addr < end; virt_addr += PAGE_SIZE) {
                int err;

                phys_addr = kvm_kaddr_to_phys(from + virt_addr - start);
                err = __create_hyp_mappings(virt_addr, PAGE_SIZE, phys_addr,
                                            prot);
                if (err)
                        return err;
        }

        return 0;
}

static int __hyp_alloc_private_va_range(unsigned long base)
{
        lockdep_assert_held(&kvm_hyp_pgd_mutex);

        if (!PAGE_ALIGNED(base))
                return -EINVAL;

        /*
         * Verify that BIT(VA_BITS - 1) hasn't been flipped by
         * allocating the new area, as it would indicate we've
         * overflowed the idmap/IO address range.
         */
        if ((base ^ io_map_base) & BIT(VA_BITS - 1))
                return -ENOMEM;

        io_map_base = base;

        return 0;
}

/**
 * hyp_alloc_private_va_range - Allocates a private VA range.
 * @size:       The size of the VA range to reserve.
 * @haddr:      The hypervisor virtual start address of the allocation.
 *
 * The private virtual address (VA) range is allocated below io_map_base
 * and aligned based on the order of @size.
 *
 * Return: 0 on success or negative error code on failure.
 */
int hyp_alloc_private_va_range(size_t size, unsigned long *haddr)
{
        unsigned long base;
        int ret = 0;

        mutex_lock(&kvm_hyp_pgd_mutex);

        /*
         * This assumes that we have enough space below the idmap
         * page to allocate our VAs. If not, the check in
         * __hyp_alloc_private_va_range() will kick. A potential
         * alternative would be to detect that overflow and switch
         * to an allocation above the idmap.
         *
         * The allocated size is always a multiple of PAGE_SIZE.
         */
        size = PAGE_ALIGN(size);
        base = io_map_base - size;
        ret = __hyp_alloc_private_va_range(base);

        mutex_unlock(&kvm_hyp_pgd_mutex);

        if (!ret)
                *haddr = base;

        return ret;
}

static int __create_hyp_private_mapping(phys_addr_t phys_addr, size_t size,
                                        unsigned long *haddr,
                                        enum kvm_pgtable_prot prot)
{
        unsigned long addr;
        int ret = 0;

        if (!kvm_host_owns_hyp_mappings()) {
                addr = kvm_call_hyp_nvhe(__pkvm_create_private_mapping,
                                         phys_addr, size, prot);
                if (IS_ERR_VALUE(addr))
                        return addr;
                *haddr = addr;

                return 0;
        }

        size = PAGE_ALIGN(size + offset_in_page(phys_addr));
        ret = hyp_alloc_private_va_range(size, &addr);
        if (ret)
                return ret;

        ret = __create_hyp_mappings(addr, size, phys_addr, prot);
        if (ret)
                return ret;

        *haddr = addr + offset_in_page(phys_addr);
        return ret;
}

int create_hyp_stack(phys_addr_t phys_addr, unsigned long *haddr)
{
        unsigned long base;
        size_t size;
        int ret;

        mutex_lock(&kvm_hyp_pgd_mutex);
        /*
         * Efficient stack verification using the NVHE_STACK_SHIFT bit implies
         * an alignment of our allocation on the order of the size.
         */
        size = NVHE_STACK_SIZE * 2;
        base = ALIGN_DOWN(io_map_base - size, size);

        ret = __hyp_alloc_private_va_range(base);

        mutex_unlock(&kvm_hyp_pgd_mutex);

        if (ret) {
                kvm_err("Cannot allocate hyp stack guard page\n");
                return ret;
        }

        /*
         * Since the stack grows downwards, map the stack to the page
         * at the higher address and leave the lower guard page
         * unbacked.
         *
         * Any valid stack address now has the NVHE_STACK_SHIFT bit as 1
         * and addresses corresponding to the guard page have the
         * NVHE_STACK_SHIFT bit as 0 - this is used for overflow detection.
         */
        ret = __create_hyp_mappings(base + NVHE_STACK_SIZE, NVHE_STACK_SIZE,
                                    phys_addr, PAGE_HYP);
        if (ret)
                kvm_err("Cannot map hyp stack\n");

        *haddr = base + size;

        return ret;
}

/**
 * create_hyp_io_mappings - Map IO into both kernel and HYP
 * @phys_addr:  The physical start address which gets mapped
 * @size:       Size of the region being mapped
 * @kaddr:      Kernel VA for this mapping
 * @haddr:      HYP VA for this mapping
 */
int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size,
                           void __iomem **kaddr,
                           void __iomem **haddr)
{
        unsigned long addr;
        int ret;

        if (is_protected_kvm_enabled())
                return -EPERM;

        *kaddr = ioremap(phys_addr, size);
        if (!*kaddr)
                return -ENOMEM;

        if (is_kernel_in_hyp_mode()) {
                *haddr = *kaddr;
                return 0;
        }

        ret = __create_hyp_private_mapping(phys_addr, size,
                                           &addr, PAGE_HYP_DEVICE);
        if (ret) {
                iounmap(*kaddr);
                *kaddr = NULL;
                *haddr = NULL;
                return ret;
        }

        *haddr = (void __iomem *)addr;
        return 0;
}

/**
 * create_hyp_exec_mappings - Map an executable range into HYP
 * @phys_addr:  The physical start address which gets mapped
 * @size:       Size of the region being mapped
 * @haddr:      HYP VA for this mapping
 */
int create_hyp_exec_mappings(phys_addr_t phys_addr, size_t size,
                             void **haddr)
{
        unsigned long addr;
        int ret;

        BUG_ON(is_kernel_in_hyp_mode());

        ret = __create_hyp_private_mapping(phys_addr, size,
                                           &addr, PAGE_HYP_EXEC);
        if (ret) {
                *haddr = NULL;
                return ret;
        }

        *haddr = (void *)addr;
        return 0;
}

static struct kvm_pgtable_mm_ops kvm_user_mm_ops = {
        /* We shouldn't need any other callback to walk the PT */
        .phys_to_virt           = kvm_host_va,
};

static int get_user_mapping_size(struct kvm *kvm, u64 addr)
{
        struct kvm_pgtable pgt = {
                .pgd            = (kvm_pteref_t)kvm->mm->pgd,
                .ia_bits        = vabits_actual,
                .start_level    = (KVM_PGTABLE_LAST_LEVEL -
                                   ARM64_HW_PGTABLE_LEVELS(pgt.ia_bits) + 1),
                .mm_ops         = &kvm_user_mm_ops,
        };
        unsigned long flags;
        kvm_pte_t pte = 0;      /* Keep GCC quiet... */
        s8 level = S8_MAX;
        int ret;

        /*
         * Disable IRQs so that we hazard against a concurrent
         * teardown of the userspace page tables (which relies on
         * IPI-ing threads).
         */
        local_irq_save(flags);
        ret = kvm_pgtable_get_leaf(&pgt, addr, &pte, &level);
        local_irq_restore(flags);

        if (ret)
                return ret;

        /*
         * Not seeing an error, but not updating level? Something went
         * deeply wrong...
         */
        if (WARN_ON(level > KVM_PGTABLE_LAST_LEVEL))
                return -EFAULT;
        if (WARN_ON(level < KVM_PGTABLE_FIRST_LEVEL))
                return -EFAULT;

        /* Oops, the userspace PTs are gone... Replay the fault */
        if (!kvm_pte_valid(pte))
                return -EAGAIN;

        return BIT(ARM64_HW_PGTABLE_LEVEL_SHIFT(level));
}

static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = {
        .zalloc_page            = stage2_memcache_zalloc_page,
        .zalloc_pages_exact     = kvm_s2_zalloc_pages_exact,
        .free_pages_exact       = kvm_s2_free_pages_exact,
        .free_unlinked_table    = stage2_free_unlinked_table,
        .get_page               = kvm_host_get_page,
        .put_page               = kvm_s2_put_page,
        .page_count             = kvm_host_page_count,
        .phys_to_virt           = kvm_host_va,
        .virt_to_phys           = kvm_host_pa,
        .dcache_clean_inval_poc = clean_dcache_guest_page,
        .icache_inval_pou       = invalidate_icache_guest_page,
};

static int kvm_init_ipa_range(struct kvm_s2_mmu *mmu, unsigned long type)
{
        u32 kvm_ipa_limit = get_kvm_ipa_limit();
        u64 mmfr0, mmfr1;
        u32 phys_shift;

        phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
        if (is_protected_kvm_enabled()) {
                phys_shift = kvm_ipa_limit;
        } else if (phys_shift) {
                if (phys_shift > kvm_ipa_limit ||
                    phys_shift < ARM64_MIN_PARANGE_BITS)
                        return -EINVAL;
        } else {
                phys_shift = KVM_PHYS_SHIFT;
                if (phys_shift > kvm_ipa_limit) {
                        pr_warn_once("%s using unsupported default IPA limit, upgrade your VMM\n",
                                     current->comm);
                        return -EINVAL;
                }
        }

        mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
        mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
        mmu->vtcr = kvm_get_vtcr(mmfr0, mmfr1, phys_shift);

        return 0;
}

/*
 * Assume that @pgt is valid and unlinked from the KVM MMU to free the
 * page-table without taking the kvm_mmu_lock and without performing any
 * TLB invalidations.
 *
 * Also, the range of addresses can be large enough to cause need_resched
 * warnings, for instance on CONFIG_PREEMPT_NONE kernels. Hence, invoke
 * cond_resched() periodically to prevent hogging the CPU for a long time
 * and schedule something else, if required.
 */
static void stage2_destroy_range(struct kvm_pgtable *pgt, phys_addr_t addr,
                                   phys_addr_t end)
{
        u64 next;

        do {
                next = stage2_range_addr_end(addr, end);
                KVM_PGT_FN(kvm_pgtable_stage2_destroy_range)(pgt, addr,
                                                             next - addr);
                if (next != end)
                        cond_resched();
        } while (addr = next, addr != end);
}

static void kvm_stage2_destroy(struct kvm_pgtable *pgt)
{
        unsigned int ia_bits = VTCR_EL2_IPA(pgt->mmu->vtcr);

        stage2_destroy_range(pgt, 0, BIT(ia_bits));
        KVM_PGT_FN(kvm_pgtable_stage2_destroy_pgd)(pgt);
}

/**
 * kvm_init_stage2_mmu - Initialise a S2 MMU structure
 * @kvm:        The pointer to the KVM structure
 * @mmu:        The pointer to the s2 MMU structure
 * @type:       The machine type of the virtual machine
 *
 * Allocates only the stage-2 HW PGD level table(s).
 * Note we don't need locking here as this is only called in two cases:
 *
 * - when the VM is created, which can't race against anything
 *
 * - when secondary kvm_s2_mmu structures are initialised for NV
 *   guests, and the caller must hold kvm->lock as this is called on a
 *   per-vcpu basis.
 */
int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long type)
{
        int cpu, err;
        struct kvm_pgtable *pgt;

        /*
         * If we already have our page tables in place, and that the
         * MMU context is the canonical one, we have a bug somewhere,
         * as this is only supposed to ever happen once per VM.
         *
         * Otherwise, we're building nested page tables, and that's
         * probably because userspace called KVM_ARM_VCPU_INIT more
         * than once on the same vcpu. Since that's actually legal,
         * don't kick a fuss and leave gracefully.
         */
        if (mmu->pgt != NULL) {
                if (kvm_is_nested_s2_mmu(kvm, mmu))
                        return 0;

                kvm_err("kvm_arch already initialized?\n");
                return -EINVAL;
        }

        err = kvm_init_ipa_range(mmu, type);
        if (err)
                return err;

        pgt = kzalloc_obj(*pgt, GFP_KERNEL_ACCOUNT);
        if (!pgt)
                return -ENOMEM;

        mmu->arch = &kvm->arch;
        err = KVM_PGT_FN(kvm_pgtable_stage2_init)(pgt, mmu, &kvm_s2_mm_ops);
        if (err)
                goto out_free_pgtable;

        mmu->pgt = pgt;
        if (is_protected_kvm_enabled())
                return 0;

        mmu->last_vcpu_ran = alloc_percpu(typeof(*mmu->last_vcpu_ran));
        if (!mmu->last_vcpu_ran) {
                err = -ENOMEM;
                goto out_destroy_pgtable;
        }

        for_each_possible_cpu(cpu)
                *per_cpu_ptr(mmu->last_vcpu_ran, cpu) = -1;

         /* The eager page splitting is disabled by default */
        mmu->split_page_chunk_size = KVM_ARM_EAGER_SPLIT_CHUNK_SIZE_DEFAULT;
        mmu->split_page_cache.gfp_zero = __GFP_ZERO;

        mmu->pgd_phys = __pa(pgt->pgd);

        if (kvm_is_nested_s2_mmu(kvm, mmu))
                kvm_init_nested_s2_mmu(mmu);

        return 0;

out_destroy_pgtable:
        kvm_stage2_destroy(pgt);
        mmu->pgt = NULL;
out_free_pgtable:
        kfree(pgt);
        return err;
}

void kvm_uninit_stage2_mmu(struct kvm *kvm)
{
        kvm_free_stage2_pgd(&kvm->arch.mmu);
        kvm_mmu_free_memory_cache(&kvm->arch.mmu.split_page_cache);
}

static void stage2_unmap_memslot(struct kvm *kvm,
                                 struct kvm_memory_slot *memslot)
{
        hva_t hva = memslot->userspace_addr;
        phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
        phys_addr_t size = PAGE_SIZE * memslot->npages;
        hva_t reg_end = hva + size;

        /*
         * A memory region could potentially cover multiple VMAs, and any holes
         * between them, so iterate over all of them to find out if we should
         * unmap any of them.
         *
         *     +--------------------------------------------+
         * +---------------+----------------+   +----------------+
         * |   : VMA 1     |      VMA 2     |   |    VMA 3  :    |
         * +---------------+----------------+   +----------------+
         *     |               memory region                |
         *     +--------------------------------------------+
         */
        do {
                struct vm_area_struct *vma;
                hva_t vm_start, vm_end;

                vma = find_vma_intersection(current->mm, hva, reg_end);
                if (!vma)
                        break;

                /*
                 * Take the intersection of this VMA with the memory region
                 */
                vm_start = max(hva, vma->vm_start);
                vm_end = min(reg_end, vma->vm_end);

                if (!(vma->vm_flags & VM_PFNMAP)) {
                        gpa_t gpa = addr + (vm_start - memslot->userspace_addr);
                        kvm_stage2_unmap_range(&kvm->arch.mmu, gpa, vm_end - vm_start, true);
                }
                hva = vm_end;
        } while (hva < reg_end);
}

/**
 * stage2_unmap_vm - Unmap Stage-2 RAM mappings
 * @kvm: The struct kvm pointer
 *
 * Go through the memregions and unmap any regular RAM
 * backing memory already mapped to the VM.
 */
void stage2_unmap_vm(struct kvm *kvm)
{
        struct kvm_memslots *slots;
        struct kvm_memory_slot *memslot;
        int idx, bkt;

        idx = srcu_read_lock(&kvm->srcu);
        mmap_read_lock(current->mm);
        write_lock(&kvm->mmu_lock);

        slots = kvm_memslots(kvm);
        kvm_for_each_memslot(memslot, bkt, slots)
                stage2_unmap_memslot(kvm, memslot);

        kvm_nested_s2_unmap(kvm, true);

        write_unlock(&kvm->mmu_lock);
        mmap_read_unlock(current->mm);
        srcu_read_unlock(&kvm->srcu, idx);
}

void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
{
        struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu);
        struct kvm_pgtable *pgt = NULL;

        write_lock(&kvm->mmu_lock);
        pgt = mmu->pgt;
        if (pgt) {
                mmu->pgd_phys = 0;
                mmu->pgt = NULL;
                free_percpu(mmu->last_vcpu_ran);
        }

        if (kvm_is_nested_s2_mmu(kvm, mmu))
                kvm_init_nested_s2_mmu(mmu);

        write_unlock(&kvm->mmu_lock);

        if (pgt) {
                kvm_stage2_destroy(pgt);
                kfree(pgt);
        }
}

static void hyp_mc_free_fn(void *addr, void *mc)
{
        struct kvm_hyp_memcache *memcache = mc;

        if (memcache->flags & HYP_MEMCACHE_ACCOUNT_STAGE2)
                kvm_account_pgtable_pages(addr, -1);

        free_page((unsigned long)addr);
}

static void *hyp_mc_alloc_fn(void *mc)
{
        struct kvm_hyp_memcache *memcache = mc;
        void *addr;

        addr = (void *)__get_free_page(GFP_KERNEL_ACCOUNT);
        if (addr && memcache->flags & HYP_MEMCACHE_ACCOUNT_STAGE2)
                kvm_account_pgtable_pages(addr, 1);

        return addr;
}

void free_hyp_memcache(struct kvm_hyp_memcache *mc)
{
        if (!is_protected_kvm_enabled())
                return;

        kfree(mc->mapping);
        __free_hyp_memcache(mc, hyp_mc_free_fn, kvm_host_va, mc);
}

int topup_hyp_memcache(struct kvm_hyp_memcache *mc, unsigned long min_pages)
{
        if (!is_protected_kvm_enabled())
                return 0;

        if (!mc->mapping) {
                mc->mapping = kzalloc_obj(struct pkvm_mapping,
                                          GFP_KERNEL_ACCOUNT);
                if (!mc->mapping)
                        return -ENOMEM;
        }

        return __topup_hyp_memcache(mc, min_pages, hyp_mc_alloc_fn,
                                    kvm_host_pa, mc);
}

/**
 * kvm_phys_addr_ioremap - map a device range to guest IPA
 *
 * @kvm:        The KVM pointer
 * @guest_ipa:  The IPA at which to insert the mapping
 * @pa:         The physical address of the device
 * @size:       The size of the mapping
 * @writable:   Whether or not to create a writable mapping
 */
int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
                          phys_addr_t pa, unsigned long size, bool writable)
{
        phys_addr_t addr;
        int ret = 0;
        struct kvm_mmu_memory_cache cache = { .gfp_zero = __GFP_ZERO };
        struct kvm_s2_mmu *mmu = &kvm->arch.mmu;
        struct kvm_pgtable *pgt = mmu->pgt;
        enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_DEVICE |
                                     KVM_PGTABLE_PROT_R |
                                     (writable ? KVM_PGTABLE_PROT_W : 0);

        if (is_protected_kvm_enabled())
                return -EPERM;

        size += offset_in_page(guest_ipa);
        guest_ipa &= PAGE_MASK;

        for (addr = guest_ipa; addr < guest_ipa + size; addr += PAGE_SIZE) {
                ret = kvm_mmu_topup_memory_cache(&cache,
                                                 kvm_mmu_cache_min_pages(mmu));
                if (ret)
                        break;

                write_lock(&kvm->mmu_lock);
                ret = KVM_PGT_FN(kvm_pgtable_stage2_map)(pgt, addr, PAGE_SIZE,
                                 pa, prot, &cache, 0);
                write_unlock(&kvm->mmu_lock);
                if (ret)
                        break;

                pa += PAGE_SIZE;
        }

        kvm_mmu_free_memory_cache(&cache);
        return ret;
}

/**
 * kvm_stage2_wp_range() - write protect stage2 memory region range
 * @mmu:        The KVM stage-2 MMU pointer
 * @addr:       Start address of range
 * @end:        End address of range
 */
void kvm_stage2_wp_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, phys_addr_t end)
{
        stage2_apply_range_resched(mmu, addr, end, KVM_PGT_FN(kvm_pgtable_stage2_wrprotect));
}

/**
 * kvm_mmu_wp_memory_region() - write protect stage 2 entries for memory slot
 * @kvm:        The KVM pointer
 * @slot:       The memory slot to write protect
 *
 * Called to start logging dirty pages after memory region
 * KVM_MEM_LOG_DIRTY_PAGES operation is called. After this function returns
 * all present PUD, PMD and PTEs are write protected in the memory region.
 * Afterwards read of dirty page log can be called.
 *
 * Acquires kvm_mmu_lock. Called with kvm->slots_lock mutex acquired,
 * serializing operations for VM memory regions.
 */
static void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot)
{
        struct kvm_memslots *slots = kvm_memslots(kvm);
        struct kvm_memory_slot *memslot = id_to_memslot(slots, slot);
        phys_addr_t start, end;

        if (WARN_ON_ONCE(!memslot))
                return;

        start = memslot->base_gfn << PAGE_SHIFT;
        end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT;

        write_lock(&kvm->mmu_lock);
        kvm_stage2_wp_range(&kvm->arch.mmu, start, end);
        kvm_nested_s2_wp(kvm);
        write_unlock(&kvm->mmu_lock);
        kvm_flush_remote_tlbs_memslot(kvm, memslot);
}

/**
 * kvm_mmu_split_memory_region() - split the stage 2 blocks into PAGE_SIZE
 *                                 pages for memory slot
 * @kvm:        The KVM pointer
 * @slot:       The memory slot to split
 *
 * Acquires kvm->mmu_lock. Called with kvm->slots_lock mutex acquired,
 * serializing operations for VM memory regions.
 */
static void kvm_mmu_split_memory_region(struct kvm *kvm, int slot)
{
        struct kvm_memslots *slots;
        struct kvm_memory_slot *memslot;
        phys_addr_t start, end;

        lockdep_assert_held(&kvm->slots_lock);

        slots = kvm_memslots(kvm);
        memslot = id_to_memslot(slots, slot);

        start = memslot->base_gfn << PAGE_SHIFT;
        end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT;

        write_lock(&kvm->mmu_lock);
        kvm_mmu_split_huge_pages(kvm, start, end);
        write_unlock(&kvm->mmu_lock);
}

/*
 * kvm_arch_mmu_enable_log_dirty_pt_masked() - enable dirty logging for selected pages.
 * @kvm:        The KVM pointer
 * @slot:       The memory slot associated with mask
 * @gfn_offset: The gfn offset in memory slot
 * @mask:       The mask of pages at offset 'gfn_offset' in this memory
 *              slot to enable dirty logging on
 *
 * Writes protect selected pages to enable dirty logging, and then
 * splits them to PAGE_SIZE. Caller must acquire kvm->mmu_lock.
 */
void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
                struct kvm_memory_slot *slot,
                gfn_t gfn_offset, unsigned long mask)
{
        phys_addr_t base_gfn = slot->base_gfn + gfn_offset;
        phys_addr_t start = (base_gfn +  __ffs(mask)) << PAGE_SHIFT;
        phys_addr_t end = (base_gfn + __fls(mask) + 1) << PAGE_SHIFT;

        lockdep_assert_held_write(&kvm->mmu_lock);

        kvm_stage2_wp_range(&kvm->arch.mmu, start, end);

        /*
         * Eager-splitting is done when manual-protect is set.  We
         * also check for initially-all-set because we can avoid
         * eager-splitting if initially-all-set is false.
         * Initially-all-set equal false implies that huge-pages were
         * already split when enabling dirty logging: no need to do it
         * again.
         */
        if (kvm_dirty_log_manual_protect_and_init_set(kvm))
                kvm_mmu_split_huge_pages(kvm, start, end);

        kvm_nested_s2_wp(kvm);
}

static void kvm_send_hwpoison_signal(unsigned long address, short lsb)
{
        send_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, lsb, current);
}

static bool fault_supports_stage2_huge_mapping(struct kvm_memory_slot *memslot,
                                               unsigned long hva,
                                               unsigned long map_size)
{
        gpa_t gpa_start;
        hva_t uaddr_start, uaddr_end;
        size_t size;

        /* The memslot and the VMA are guaranteed to be aligned to PAGE_SIZE */
        if (map_size == PAGE_SIZE)
                return true;

        /* pKVM only supports PMD_SIZE huge-mappings */
        if (is_protected_kvm_enabled() && map_size != PMD_SIZE)
                return false;

        size = memslot->npages * PAGE_SIZE;

        gpa_start = memslot->base_gfn << PAGE_SHIFT;

        uaddr_start = memslot->userspace_addr;
        uaddr_end = uaddr_start + size;

        /*
         * Pages belonging to memslots that don't have the same alignment
         * within a PMD/PUD for userspace and IPA cannot be mapped with stage-2
         * PMD/PUD entries, because we'll end up mapping the wrong pages.
         *
         * Consider a layout like the following:
         *
         *    memslot->userspace_addr:
         *    +-----+--------------------+--------------------+---+
         *    |abcde|fgh  Stage-1 block  |    Stage-1 block tv|xyz|
         *    +-----+--------------------+--------------------+---+
         *
         *    memslot->base_gfn << PAGE_SHIFT:
         *      +---+--------------------+--------------------+-----+
         *      |abc|def  Stage-2 block  |    Stage-2 block   |tvxyz|
         *      +---+--------------------+--------------------+-----+
         *
         * If we create those stage-2 blocks, we'll end up with this incorrect
         * mapping:
         *   d -> f
         *   e -> g
         *   f -> h
         */
        if ((gpa_start & (map_size - 1)) != (uaddr_start & (map_size - 1)))
                return false;

        /*
         * Next, let's make sure we're not trying to map anything not covered
         * by the memslot. This means we have to prohibit block size mappings
         * for the beginning and end of a non-block aligned and non-block sized
         * memory slot (illustrated by the head and tail parts of the
         * userspace view above containing pages 'abcde' and 'xyz',
         * respectively).
         *
         * Note that it doesn't matter if we do the check using the
         * userspace_addr or the base_gfn, as both are equally aligned (per
         * the check above) and equally sized.
         */
        return (hva & ~(map_size - 1)) >= uaddr_start &&
               (hva & ~(map_size - 1)) + map_size <= uaddr_end;
}

/*
 * Check if the given hva is backed by a transparent huge page (THP) and
 * whether it can be mapped using block mapping in stage2. If so, adjust
 * the stage2 PFN and IPA accordingly. Only PMD_SIZE THPs are currently
 * supported. This will need to be updated to support other THP sizes.
 *
 * Returns the size of the mapping.
 */
static long
transparent_hugepage_adjust(struct kvm *kvm, struct kvm_memory_slot *memslot,
                            unsigned long hva, kvm_pfn_t *pfnp, gfn_t *gfnp)
{
        kvm_pfn_t pfn = *pfnp;
        gfn_t gfn = *gfnp;

        /*
         * Make sure the adjustment is done only for THP pages. Also make
         * sure that the HVA and IPA are sufficiently aligned and that the
         * block map is contained within the memslot.
         */
        if (fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE)) {
                int sz = get_user_mapping_size(kvm, hva);

                if (sz < 0)
                        return sz;

                if (sz < PMD_SIZE)
                        return PAGE_SIZE;

                gfn &= ~(PTRS_PER_PMD - 1);
                *gfnp = gfn;
                pfn &= ~(PTRS_PER_PMD - 1);
                *pfnp = pfn;

                return PMD_SIZE;
        }

        /* Use page mapping if we cannot use block mapping. */
        return PAGE_SIZE;
}

static int get_vma_page_shift(struct vm_area_struct *vma, unsigned long hva)
{
        unsigned long pa;

        if (is_vm_hugetlb_page(vma) && !(vma->vm_flags & VM_PFNMAP))
                return huge_page_shift(hstate_vma(vma));

        if (!(vma->vm_flags & VM_PFNMAP))
                return PAGE_SHIFT;

        VM_BUG_ON(is_vm_hugetlb_page(vma));

        pa = (vma->vm_pgoff << PAGE_SHIFT) + (hva - vma->vm_start);

#ifndef __PAGETABLE_PMD_FOLDED
        if ((hva & (PUD_SIZE - 1)) == (pa & (PUD_SIZE - 1)) &&
            ALIGN_DOWN(hva, PUD_SIZE) >= vma->vm_start &&
            ALIGN(hva, PUD_SIZE) <= vma->vm_end)
                return PUD_SHIFT;
#endif

        if ((hva & (PMD_SIZE - 1)) == (pa & (PMD_SIZE - 1)) &&
            ALIGN_DOWN(hva, PMD_SIZE) >= vma->vm_start &&
            ALIGN(hva, PMD_SIZE) <= vma->vm_end)
                return PMD_SHIFT;

        return PAGE_SHIFT;
}

/*
 * The page will be mapped in stage 2 as Normal Cacheable, so the VM will be
 * able to see the page's tags and therefore they must be initialised first. If
 * PG_mte_tagged is set, tags have already been initialised.
 *
 * Must be called with kvm->mmu_lock held to ensure the memory remains mapped
 * while the tags are zeroed.
 */
static void sanitise_mte_tags(struct kvm *kvm, kvm_pfn_t pfn,
                              unsigned long size)
{
        unsigned long i, nr_pages = size >> PAGE_SHIFT;
        struct page *page = pfn_to_page(pfn);
        struct folio *folio = page_folio(page);

        if (!kvm_has_mte(kvm))
                return;

        if (is_zero_pfn(pfn)) {
                WARN_ON_ONCE(nr_pages != 1);
                return;
        }

        if (folio_test_hugetlb(folio)) {
                /* Hugetlb has MTE flags set on head page only */
                if (folio_try_hugetlb_mte_tagging(folio)) {
                        for (i = 0; i < nr_pages; i++, page++)
                                mte_clear_page_tags(page_address(page));
                        folio_set_hugetlb_mte_tagged(folio);
                }
                return;
        }

        for (i = 0; i < nr_pages; i++, page++) {
                if (try_page_mte_tagging(page)) {
                        mte_clear_page_tags(page_address(page));
                        set_page_mte_tagged(page);
                }
        }
}

static bool kvm_vma_mte_allowed(struct vm_area_struct *vma)
{
        return vma->vm_flags & VM_MTE_ALLOWED;
}

static bool kvm_vma_is_cacheable(struct vm_area_struct *vma)
{
        switch (FIELD_GET(PTE_ATTRINDX_MASK, pgprot_val(vma->vm_page_prot))) {
        case MT_NORMAL_NC:
        case MT_DEVICE_nGnRnE:
        case MT_DEVICE_nGnRE:
                return false;
        default:
                return true;
        }
}

static void *get_mmu_memcache(struct kvm_vcpu *vcpu)
{
        if (!is_protected_kvm_enabled())
                return &vcpu->arch.mmu_page_cache;
        else
                return &vcpu->arch.pkvm_memcache;
}

static int topup_mmu_memcache(struct kvm_vcpu *vcpu, void *memcache)
{
        int min_pages = kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu);

        if (!is_protected_kvm_enabled())
                return kvm_mmu_topup_memory_cache(memcache, min_pages);

        return topup_hyp_memcache(memcache, min_pages);
}

/*
 * Potentially reduce shadow S2 permissions to match the guest's own S2. For
 * exec faults, we'd only reach this point if the guest actually allowed it (see
 * kvm_s2_handle_perm_fault).
 *
 * Also encode the level of the original translation in the SW bits of the leaf
 * entry as a proxy for the span of that translation. This will be retrieved on
 * TLB invalidation from the guest and used to limit the invalidation scope if a
 * TTL hint or a range isn't provided.
 */
static enum kvm_pgtable_prot adjust_nested_fault_perms(struct kvm_s2_trans *nested,
                                                       enum kvm_pgtable_prot prot)
{
        if (!kvm_s2_trans_writable(nested))
                prot &= ~KVM_PGTABLE_PROT_W;
        if (!kvm_s2_trans_readable(nested))
                prot &= ~KVM_PGTABLE_PROT_R;

        return prot | kvm_encode_nested_level(nested);
}

static enum kvm_pgtable_prot adjust_nested_exec_perms(struct kvm *kvm,
                                                      struct kvm_s2_trans *nested,
                                                      enum kvm_pgtable_prot prot)
{
        if (!kvm_s2_trans_exec_el0(kvm, nested))
                prot &= ~KVM_PGTABLE_PROT_UX;
        if (!kvm_s2_trans_exec_el1(kvm, nested))
                prot &= ~KVM_PGTABLE_PROT_PX;

        return prot;
}

struct kvm_s2_fault_desc {
        struct kvm_vcpu         *vcpu;
        phys_addr_t             fault_ipa;
        struct kvm_s2_trans     *nested;
        struct kvm_memory_slot  *memslot;
        unsigned long           hva;
};

static int gmem_abort(const struct kvm_s2_fault_desc *s2fd)
{
        bool write_fault, exec_fault;
        bool perm_fault = kvm_vcpu_trap_is_permission_fault(s2fd->vcpu);
        enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_SHARED;
        enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
        struct kvm_pgtable *pgt = s2fd->vcpu->arch.hw_mmu->pgt;
        unsigned long mmu_seq;
        struct page *page;
        struct kvm *kvm = s2fd->vcpu->kvm;
        void *memcache = NULL;
        kvm_pfn_t pfn;
        gfn_t gfn;
        int ret;

        if (!perm_fault) {
                memcache = get_mmu_memcache(s2fd->vcpu);
                ret = topup_mmu_memcache(s2fd->vcpu, memcache);
                if (ret)
                        return ret;
        }

        if (s2fd->nested)
                gfn = kvm_s2_trans_output(s2fd->nested) >> PAGE_SHIFT;
        else
                gfn = s2fd->fault_ipa >> PAGE_SHIFT;

        write_fault = kvm_is_write_fault(s2fd->vcpu);
        exec_fault = kvm_vcpu_trap_is_exec_fault(s2fd->vcpu);

        VM_WARN_ON_ONCE(write_fault && exec_fault);

        mmu_seq = kvm->mmu_invalidate_seq;
        /* Pairs with the smp_wmb() in kvm_mmu_invalidate_end(). */
        smp_rmb();

        ret = kvm_gmem_get_pfn(kvm, s2fd->memslot, gfn, &pfn, &page, NULL);
        if (ret) {
                kvm_prepare_memory_fault_exit(s2fd->vcpu, s2fd->fault_ipa, PAGE_SIZE,
                                              write_fault, exec_fault, false);
                return ret;
        }

        if (!(s2fd->memslot->flags & KVM_MEM_READONLY))
                prot |= KVM_PGTABLE_PROT_W;

        if (s2fd->nested)
                prot = adjust_nested_fault_perms(s2fd->nested, prot);

        if (exec_fault || cpus_have_final_cap(ARM64_HAS_CACHE_DIC))
                prot |= KVM_PGTABLE_PROT_X;

        if (s2fd->nested)
                prot = adjust_nested_exec_perms(kvm, s2fd->nested, prot);

        kvm_fault_lock(kvm);
        if (mmu_invalidate_retry(kvm, mmu_seq)) {
                ret = -EAGAIN;
                goto out_unlock;
        }

        if (perm_fault) {
                /*
                 * Drop the SW bits in favour of those stored in the
                 * PTE, which will be preserved.
                 */
                prot &= ~KVM_NV_GUEST_MAP_SZ;
                ret = KVM_PGT_FN(kvm_pgtable_stage2_relax_perms)(pgt, s2fd->fault_ipa,
                                                                 prot, flags);
        } else {
                ret = KVM_PGT_FN(kvm_pgtable_stage2_map)(pgt, s2fd->fault_ipa, PAGE_SIZE,
                                                         __pfn_to_phys(pfn), prot,
                                                         memcache, flags);
        }

out_unlock:
        kvm_release_faultin_page(kvm, page, !!ret, prot & KVM_PGTABLE_PROT_W);
        kvm_fault_unlock(kvm);

        if ((prot & KVM_PGTABLE_PROT_W) && !ret)
                mark_page_dirty_in_slot(kvm, s2fd->memslot, gfn);

        return ret != -EAGAIN ? ret : 0;
}

struct kvm_s2_fault_vma_info {
        unsigned long   mmu_seq;
        long            vma_pagesize;
        vm_flags_t      vm_flags;
        unsigned long   max_map_size;
        struct page     *page;
        kvm_pfn_t       pfn;
        gfn_t           gfn;
        bool            device;
        bool            mte_allowed;
        bool            is_vma_cacheable;
        bool            map_writable;
        bool            map_non_cacheable;
};

static int pkvm_mem_abort(const struct kvm_s2_fault_desc *s2fd)
{
        unsigned int flags = FOLL_HWPOISON | FOLL_LONGTERM | FOLL_WRITE;
        struct kvm_vcpu *vcpu = s2fd->vcpu;
        struct kvm_pgtable *pgt = vcpu->arch.hw_mmu->pgt;
        struct mm_struct *mm = current->mm;
        struct kvm *kvm = vcpu->kvm;
        void *hyp_memcache;
        struct page *page;
        int ret;

        hyp_memcache = get_mmu_memcache(vcpu);
        ret = topup_mmu_memcache(vcpu, hyp_memcache);
        if (ret)
                return -ENOMEM;

        ret = account_locked_vm(mm, 1, true);
        if (ret)
                return ret;

        mmap_read_lock(mm);
        ret = pin_user_pages(s2fd->hva, 1, flags, &page);
        mmap_read_unlock(mm);

        if (ret == -EHWPOISON) {
                kvm_send_hwpoison_signal(s2fd->hva, PAGE_SHIFT);
                ret = 0;
                goto dec_account;
        } else if (ret != 1) {
                ret = -EFAULT;
                goto dec_account;
        } else if (!folio_test_swapbacked(page_folio(page))) {
                /*
                 * We really can't deal with page-cache pages returned by GUP
                 * because (a) we may trigger writeback of a page for which we
                 * no longer have access and (b) page_mkclean() won't find the
                 * stage-2 mapping in the rmap so we can get out-of-whack with
                 * the filesystem when marking the page dirty during unpinning
                 * (see cc5095747edf ("ext4: don't BUG if someone dirty pages
                 * without asking ext4 first")).
                 *
                 * Ideally we'd just restrict ourselves to anonymous pages, but
                 * we also want to allow memfd (i.e. shmem) pages, so check for
                 * pages backed by swap in the knowledge that the GUP pin will
                 * prevent try_to_unmap() from succeeding.
                 */
                ret = -EIO;
                goto unpin;
        }

        write_lock(&kvm->mmu_lock);
        ret = pkvm_pgtable_stage2_map(pgt, s2fd->fault_ipa, PAGE_SIZE,
                                      page_to_phys(page), KVM_PGTABLE_PROT_RWX,
                                      hyp_memcache, 0);
        write_unlock(&kvm->mmu_lock);
        if (ret) {
                if (ret == -EAGAIN)
                        ret = 0;
                goto unpin;
        }

        return 0;
unpin:
        unpin_user_pages(&page, 1);
dec_account:
        account_locked_vm(mm, 1, false);
        return ret;
}

static short kvm_s2_resolve_vma_size(const struct kvm_s2_fault_desc *s2fd,
                                     struct kvm_s2_fault_vma_info *s2vi,
                                     struct vm_area_struct *vma)
{
        short vma_shift;

        if (memslot_is_logging(s2fd->memslot)) {
                s2vi->max_map_size = PAGE_SIZE;
                vma_shift = PAGE_SHIFT;
        } else {
                s2vi->max_map_size = PUD_SIZE;
                vma_shift = get_vma_page_shift(vma, s2fd->hva);
        }

        switch (vma_shift) {
#ifndef __PAGETABLE_PMD_FOLDED
        case PUD_SHIFT:
                if (fault_supports_stage2_huge_mapping(s2fd->memslot, s2fd->hva, PUD_SIZE))
                        break;
                fallthrough;
#endif
        case CONT_PMD_SHIFT:
                vma_shift = PMD_SHIFT;
                fallthrough;
        case PMD_SHIFT:
                if (fault_supports_stage2_huge_mapping(s2fd->memslot, s2fd->hva, PMD_SIZE))
                        break;
                fallthrough;
        case CONT_PTE_SHIFT:
                vma_shift = PAGE_SHIFT;
                s2vi->max_map_size = PAGE_SIZE;
                fallthrough;
        case PAGE_SHIFT:
                break;
        default:
                WARN_ONCE(1, "Unknown vma_shift %d", vma_shift);
        }

        if (s2fd->nested) {
                unsigned long max_map_size;

                max_map_size = min(s2vi->max_map_size, PUD_SIZE);

                /*
                 * If we're about to create a shadow stage 2 entry, then we
                 * can only create a block mapping if the guest stage 2 page
                 * table uses at least as big a mapping.
                 */
                max_map_size = min(kvm_s2_trans_size(s2fd->nested), max_map_size);

                /*
                 * Be careful that if the mapping size falls between
                 * two host sizes, take the smallest of the two.
                 */
                if (max_map_size >= PMD_SIZE && max_map_size < PUD_SIZE)
                        max_map_size = PMD_SIZE;
                else if (max_map_size >= PAGE_SIZE && max_map_size < PMD_SIZE)
                        max_map_size = PAGE_SIZE;

                s2vi->max_map_size = max_map_size;
                vma_shift = min_t(short, vma_shift, __ffs(max_map_size));
        }

        return vma_shift;
}

static bool kvm_s2_fault_is_perm(const struct kvm_s2_fault_desc *s2fd)
{
        return kvm_vcpu_trap_is_permission_fault(s2fd->vcpu);
}

static int kvm_s2_fault_get_vma_info(const struct kvm_s2_fault_desc *s2fd,
                                     struct kvm_s2_fault_vma_info *s2vi)
{
        struct vm_area_struct *vma;
        struct kvm *kvm = s2fd->vcpu->kvm;

        mmap_read_lock(current->mm);
        vma = vma_lookup(current->mm, s2fd->hva);
        if (unlikely(!vma)) {
                kvm_err("Failed to find VMA for hva 0x%lx\n", s2fd->hva);
                mmap_read_unlock(current->mm);
                return -EFAULT;
        }

        s2vi->vma_pagesize = BIT(kvm_s2_resolve_vma_size(s2fd, s2vi, vma));

        /*
         * Both the canonical IPA and fault IPA must be aligned to the
         * mapping size to ensure we find the right PFN and lay down the
         * mapping in the right place.
         */
        s2vi->gfn = ALIGN_DOWN(s2fd->fault_ipa, s2vi->vma_pagesize) >> PAGE_SHIFT;

        s2vi->mte_allowed = kvm_vma_mte_allowed(vma);

        s2vi->vm_flags = vma->vm_flags;

        s2vi->is_vma_cacheable = kvm_vma_is_cacheable(vma);

        /*
         * Read mmu_invalidate_seq so that KVM can detect if the results of
         * vma_lookup() or __kvm_faultin_pfn() become stale prior to
         * acquiring kvm->mmu_lock.
         *
         * Rely on mmap_read_unlock() for an implicit smp_rmb(), which pairs
         * with the smp_wmb() in kvm_mmu_invalidate_end().
         */
        s2vi->mmu_seq = kvm->mmu_invalidate_seq;
        mmap_read_unlock(current->mm);

        return 0;
}

static gfn_t get_canonical_gfn(const struct kvm_s2_fault_desc *s2fd,
                               const struct kvm_s2_fault_vma_info *s2vi)
{
        phys_addr_t ipa;

        if (!s2fd->nested)
                return s2vi->gfn;

        ipa = kvm_s2_trans_output(s2fd->nested);
        return ALIGN_DOWN(ipa, s2vi->vma_pagesize) >> PAGE_SHIFT;
}

static int kvm_s2_fault_pin_pfn(const struct kvm_s2_fault_desc *s2fd,
                                struct kvm_s2_fault_vma_info *s2vi)
{
        int ret;

        ret = kvm_s2_fault_get_vma_info(s2fd, s2vi);
        if (ret)
                return ret;

        s2vi->pfn = __kvm_faultin_pfn(s2fd->memslot, get_canonical_gfn(s2fd, s2vi),
                                      kvm_is_write_fault(s2fd->vcpu) ? FOLL_WRITE : 0,
                                      &s2vi->map_writable, &s2vi->page);
        if (unlikely(is_error_noslot_pfn(s2vi->pfn))) {
                if (s2vi->pfn == KVM_PFN_ERR_HWPOISON) {
                        kvm_send_hwpoison_signal(s2fd->hva, __ffs(s2vi->vma_pagesize));
                        return 0;
                }
                return -EFAULT;
        }

        /*
         * Check if this is non-struct page memory PFN, and cannot support
         * CMOs. It could potentially be unsafe to access as cacheable.
         */
        if (s2vi->vm_flags & (VM_PFNMAP | VM_MIXEDMAP) && !pfn_is_map_memory(s2vi->pfn)) {
                if (s2vi->is_vma_cacheable) {
                        /*
                         * Whilst the VMA owner expects cacheable mapping to this
                         * PFN, hardware also has to support the FWB and CACHE DIC
                         * features.
                         *
                         * ARM64 KVM relies on kernel VA mapping to the PFN to
                         * perform cache maintenance as the CMO instructions work on
                         * virtual addresses. VM_PFNMAP region are not necessarily
                         * mapped to a KVA and hence the presence of hardware features
                         * S2FWB and CACHE DIC are mandatory to avoid the need for
                         * cache maintenance.
                         */
                        if (!kvm_supports_cacheable_pfnmap()) {
                                kvm_release_faultin_page(s2fd->vcpu->kvm, s2vi->page, true, false);
                                return -EFAULT;
                        }
                } else {
                        /*
                         * If the page was identified as device early by looking at
                         * the VMA flags, vma_pagesize is already representing the
                         * largest quantity we can map.  If instead it was mapped
                         * via __kvm_faultin_pfn(), vma_pagesize is set to PAGE_SIZE
                         * and must not be upgraded.
                         *
                         * In both cases, we don't let transparent_hugepage_adjust()
                         * change things at the last minute.
                         */
                        s2vi->map_non_cacheable = true;
                }

                s2vi->device = true;
        }

        return 1;
}

static int kvm_s2_fault_compute_prot(const struct kvm_s2_fault_desc *s2fd,
                                     const struct kvm_s2_fault_vma_info *s2vi,
                                     enum kvm_pgtable_prot *prot)
{
        struct kvm *kvm = s2fd->vcpu->kvm;

        if (kvm_vcpu_trap_is_exec_fault(s2fd->vcpu) && s2vi->map_non_cacheable)
                return -ENOEXEC;

        /*
         * Guest performs atomic/exclusive operations on memory with unsupported
         * attributes (e.g. ld64b/st64b on normal memory when no FEAT_LS64WB)
         * and trigger the exception here. Since the memslot is valid, inject
         * the fault back to the guest.
         */
        if (esr_fsc_is_excl_atomic_fault(kvm_vcpu_get_esr(s2fd->vcpu))) {
                kvm_inject_dabt_excl_atomic(s2fd->vcpu, kvm_vcpu_get_hfar(s2fd->vcpu));
                return 1;
        }

        *prot = KVM_PGTABLE_PROT_R;

        if (s2vi->map_writable && (s2vi->device ||
                                   !memslot_is_logging(s2fd->memslot) ||
                                   kvm_is_write_fault(s2fd->vcpu)))
                *prot |= KVM_PGTABLE_PROT_W;

        if (s2fd->nested)
                *prot = adjust_nested_fault_perms(s2fd->nested, *prot);

        if (kvm_vcpu_trap_is_exec_fault(s2fd->vcpu))
                *prot |= KVM_PGTABLE_PROT_X;

        if (s2vi->map_non_cacheable)
                *prot |= (s2vi->vm_flags & VM_ALLOW_ANY_UNCACHED) ?
                        KVM_PGTABLE_PROT_NORMAL_NC : KVM_PGTABLE_PROT_DEVICE;
        else if (cpus_have_final_cap(ARM64_HAS_CACHE_DIC))
                *prot |= KVM_PGTABLE_PROT_X;

        if (s2fd->nested)
                *prot = adjust_nested_exec_perms(kvm, s2fd->nested, *prot);

        if (!kvm_s2_fault_is_perm(s2fd) && !s2vi->map_non_cacheable && kvm_has_mte(kvm)) {
                /* Check the VMM hasn't introduced a new disallowed VMA */
                if (!s2vi->mte_allowed)
                        return -EFAULT;
        }

        return 0;
}

static int kvm_s2_fault_map(const struct kvm_s2_fault_desc *s2fd,
                            const struct kvm_s2_fault_vma_info *s2vi,
                            enum kvm_pgtable_prot prot,
                            void *memcache)
{
        enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_SHARED;
        bool writable = prot & KVM_PGTABLE_PROT_W;
        struct kvm *kvm = s2fd->vcpu->kvm;
        struct kvm_pgtable *pgt;
        long perm_fault_granule;
        long mapping_size;
        kvm_pfn_t pfn;
        gfn_t gfn;
        int ret;

        kvm_fault_lock(kvm);
        pgt = s2fd->vcpu->arch.hw_mmu->pgt;
        ret = -EAGAIN;
        if (mmu_invalidate_retry(kvm, s2vi->mmu_seq))
                goto out_unlock;

        perm_fault_granule = (kvm_s2_fault_is_perm(s2fd) ?
                              kvm_vcpu_trap_get_perm_fault_granule(s2fd->vcpu) : 0);
        mapping_size = s2vi->vma_pagesize;
        pfn = s2vi->pfn;
        gfn = s2vi->gfn;

        /*
         * If we are not forced to use page mapping, check if we are
         * backed by a THP and thus use block mapping if possible.
         */
        if (mapping_size == PAGE_SIZE &&
            !(s2vi->max_map_size == PAGE_SIZE || s2vi->map_non_cacheable)) {
                if (perm_fault_granule > PAGE_SIZE) {
                        mapping_size = perm_fault_granule;
                } else {
                        mapping_size = transparent_hugepage_adjust(kvm, s2fd->memslot,
                                                                   s2fd->hva, &pfn,
                                                                   &gfn);
                        if (mapping_size < 0) {
                                ret = mapping_size;
                                goto out_unlock;
                        }
                }
        }

        if (!perm_fault_granule && !s2vi->map_non_cacheable && kvm_has_mte(kvm))
                sanitise_mte_tags(kvm, pfn, mapping_size);

        /*
         * Under the premise of getting a FSC_PERM fault, we just need to relax
         * permissions only if mapping_size equals perm_fault_granule. Otherwise,
         * kvm_pgtable_stage2_map() should be called to change block size.
         */
        if (mapping_size == perm_fault_granule) {
                /*
                 * Drop the SW bits in favour of those stored in the
                 * PTE, which will be preserved.
                 */
                prot &= ~KVM_NV_GUEST_MAP_SZ;
                ret = KVM_PGT_FN(kvm_pgtable_stage2_relax_perms)(pgt, gfn_to_gpa(gfn),
                                                                 prot, flags);
        } else {
                ret = KVM_PGT_FN(kvm_pgtable_stage2_map)(pgt, gfn_to_gpa(gfn), mapping_size,
                                                         __pfn_to_phys(pfn), prot,
                                                         memcache, flags);
        }

out_unlock:
        kvm_release_faultin_page(kvm, s2vi->page, !!ret, writable);
        kvm_fault_unlock(kvm);

        /*
         * Mark the page dirty only if the fault is handled successfully,
         * making sure we adjust the canonical IPA if the mapping size has
         * been updated (via a THP upgrade, for example).
         */
        if (writable && !ret) {
                phys_addr_t ipa = gfn_to_gpa(get_canonical_gfn(s2fd, s2vi));
                ipa &= ~(mapping_size - 1);
                mark_page_dirty_in_slot(kvm, s2fd->memslot, gpa_to_gfn(ipa));
        }

        if (ret != -EAGAIN)
                return ret;
        return 0;
}

static int user_mem_abort(const struct kvm_s2_fault_desc *s2fd)
{
        bool perm_fault = kvm_vcpu_trap_is_permission_fault(s2fd->vcpu);
        struct kvm_s2_fault_vma_info s2vi = {};
        enum kvm_pgtable_prot prot;
        void *memcache;
        int ret;

        /*
         * Permission faults just need to update the existing leaf entry,
         * and so normally don't require allocations from the memcache. The
         * only exception to this is when dirty logging is enabled at runtime
         * and a write fault needs to collapse a block entry into a table.
         */
        memcache = get_mmu_memcache(s2fd->vcpu);
        if (!perm_fault || (memslot_is_logging(s2fd->memslot) &&
                            kvm_is_write_fault(s2fd->vcpu))) {
                ret = topup_mmu_memcache(s2fd->vcpu, memcache);
                if (ret)
                        return ret;
        }

        /*
         * Let's check if we will get back a huge page backed by hugetlbfs, or
         * get block mapping for device MMIO region.
         */
        ret = kvm_s2_fault_pin_pfn(s2fd, &s2vi);
        if (ret != 1)
                return ret;

        ret = kvm_s2_fault_compute_prot(s2fd, &s2vi, &prot);
        if (ret) {
                kvm_release_page_unused(s2vi.page);
                return ret;
        }

        return kvm_s2_fault_map(s2fd, &s2vi, prot, memcache);
}

/* Resolve the access fault by making the page young again. */
static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
{
        enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_SHARED;
        struct kvm_s2_mmu *mmu;

        trace_kvm_access_fault(fault_ipa);

        read_lock(&vcpu->kvm->mmu_lock);
        mmu = vcpu->arch.hw_mmu;
        KVM_PGT_FN(kvm_pgtable_stage2_mkyoung)(mmu->pgt, fault_ipa, flags);
        read_unlock(&vcpu->kvm->mmu_lock);
}

/*
 * Returns true if the SEA should be handled locally within KVM if the abort
 * is caused by a kernel memory allocation (e.g. stage-2 table memory).
 */
static bool host_owns_sea(struct kvm_vcpu *vcpu, u64 esr)
{
        /*
         * Without FEAT_RAS HCR_EL2.TEA is RES0, meaning any external abort
         * taken from a guest EL to EL2 is due to a host-imposed access (e.g.
         * stage-2 PTW).
         */
        if (!cpus_have_final_cap(ARM64_HAS_RAS_EXTN))
                return true;

        /* KVM owns the VNCR when the vCPU isn't in a nested context. */
        if (is_hyp_ctxt(vcpu) && !kvm_vcpu_trap_is_iabt(vcpu) && (esr & ESR_ELx_VNCR))
                return true;

        /*
         * Determining if an external abort during a table walk happened at
         * stage-2 is only possible with S1PTW is set. Otherwise, since KVM
         * sets HCR_EL2.TEA, SEAs due to a stage-1 walk (i.e. accessing the
         * PA of the stage-1 descriptor) can reach here and are reported
         * with a TTW ESR value.
         */
        return (esr_fsc_is_sea_ttw(esr) && (esr & ESR_ELx_S1PTW));
}

int kvm_handle_guest_sea(struct kvm_vcpu *vcpu)
{
        struct kvm *kvm = vcpu->kvm;
        struct kvm_run *run = vcpu->run;
        u64 esr = kvm_vcpu_get_esr(vcpu);
        u64 esr_mask = ESR_ELx_EC_MASK  |
                       ESR_ELx_IL       |
                       ESR_ELx_FnV      |
                       ESR_ELx_EA       |
                       ESR_ELx_CM       |
                       ESR_ELx_WNR      |
                       ESR_ELx_FSC;
        u64 ipa;

        /*
         * Give APEI the opportunity to claim the abort before handling it
         * within KVM. apei_claim_sea() expects to be called with IRQs enabled.
         */
        lockdep_assert_irqs_enabled();
        if (apei_claim_sea(NULL) == 0)
                return 1;

        if (host_owns_sea(vcpu, esr) ||
            !test_bit(KVM_ARCH_FLAG_EXIT_SEA, &vcpu->kvm->arch.flags))
                return kvm_inject_serror(vcpu);

        /* ESR_ELx.SET is RES0 when FEAT_RAS isn't implemented. */
        if (kvm_has_ras(kvm))
                esr_mask |= ESR_ELx_SET_MASK;

        /*
         * Exit to userspace, and provide faulting guest virtual and physical
         * addresses in case userspace wants to emulate SEA to guest by
         * writing to FAR_ELx and HPFAR_ELx registers.
         */
        memset(&run->arm_sea, 0, sizeof(run->arm_sea));
        run->exit_reason = KVM_EXIT_ARM_SEA;
        run->arm_sea.esr = esr & esr_mask;

        if (!(esr & ESR_ELx_FnV))
                run->arm_sea.gva = kvm_vcpu_get_hfar(vcpu);

        ipa = kvm_vcpu_get_fault_ipa(vcpu);
        if (ipa != INVALID_GPA) {
                run->arm_sea.flags |= KVM_EXIT_ARM_SEA_FLAG_GPA_VALID;
                run->arm_sea.gpa = ipa;
        }

        return 0;
}

/**
 * kvm_handle_guest_abort - handles all 2nd stage aborts
 * @vcpu:       the VCPU pointer
 *
 * Any abort that gets to the host is almost guaranteed to be caused by a
 * missing second stage translation table entry, which can mean that either the
 * guest simply needs more memory and we must allocate an appropriate page or it
 * can mean that the guest tried to access I/O memory, which is emulated by user
 * space. The distinction is based on the IPA causing the fault and whether this
 * memory region has been registered as standard RAM by user space.
 */
int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
{
        struct kvm_s2_trans nested_trans, *nested = NULL;
        unsigned long esr;
        phys_addr_t fault_ipa; /* The address we faulted on */
        phys_addr_t ipa; /* Always the IPA in the L1 guest phys space */
        struct kvm_memory_slot *memslot;
        unsigned long hva;
        bool is_iabt, write_fault, writable;
        gfn_t gfn;
        int ret, idx;

        if (kvm_vcpu_abt_issea(vcpu))
                return kvm_handle_guest_sea(vcpu);

        esr = kvm_vcpu_get_esr(vcpu);

        /*
         * The fault IPA should be reliable at this point as we're not dealing
         * with an SEA.
         */
        ipa = fault_ipa = kvm_vcpu_get_fault_ipa(vcpu);
        if (KVM_BUG_ON(ipa == INVALID_GPA, vcpu->kvm))
                return -EFAULT;

        is_iabt = kvm_vcpu_trap_is_iabt(vcpu);

        if (esr_fsc_is_translation_fault(esr)) {
                /* Beyond sanitised PARange (which is the IPA limit) */
                if (fault_ipa >= BIT_ULL(get_kvm_ipa_limit())) {
                        kvm_inject_size_fault(vcpu);
                        return 1;
                }

                /* Falls between the IPA range and the PARange? */
                if (fault_ipa >= BIT_ULL(VTCR_EL2_IPA(vcpu->arch.hw_mmu->vtcr))) {
                        fault_ipa |= FAR_TO_FIPA_OFFSET(kvm_vcpu_get_hfar(vcpu));

                        return kvm_inject_sea(vcpu, is_iabt, fault_ipa);
                }
        }

        trace_kvm_guest_fault(*vcpu_pc(vcpu), kvm_vcpu_get_esr(vcpu),
                              kvm_vcpu_get_hfar(vcpu), fault_ipa);

        /* Check the stage-2 fault is trans. fault or write fault */
        if (!esr_fsc_is_translation_fault(esr) &&
            !esr_fsc_is_permission_fault(esr) &&
            !esr_fsc_is_access_flag_fault(esr) &&
            !esr_fsc_is_excl_atomic_fault(esr)) {
                kvm_err("Unsupported FSC: EC=%#x xFSC=%#lx ESR_EL2=%#lx\n",
                        kvm_vcpu_trap_get_class(vcpu),
                        (unsigned long)kvm_vcpu_trap_get_fault(vcpu),
                        (unsigned long)kvm_vcpu_get_esr(vcpu));
                return -EFAULT;
        }

        idx = srcu_read_lock(&vcpu->kvm->srcu);

        /*
         * We may have faulted on a shadow stage 2 page table if we are
         * running a nested guest.  In this case, we have to resolve the L2
         * IPA to the L1 IPA first, before knowing what kind of memory should
         * back the L1 IPA.
         *
         * If the shadow stage 2 page table walk faults, then we simply inject
         * this to the guest and carry on.
         *
         * If there are no shadow S2 PTs because S2 is disabled, there is
         * nothing to walk and we treat it as a 1:1 before going through the
         * canonical translation.
         */
        if (kvm_is_nested_s2_mmu(vcpu->kvm,vcpu->arch.hw_mmu) &&
            vcpu->arch.hw_mmu->nested_stage2_enabled) {
                u32 esr;

                ret = kvm_walk_nested_s2(vcpu, fault_ipa, &nested_trans);
                if (ret == -EAGAIN) {
                        ret = 1;
                        goto out_unlock;
                }

                if (ret) {
                        esr = kvm_s2_trans_esr(&nested_trans);
                        kvm_inject_s2_fault(vcpu, esr);
                        goto out_unlock;
                }

                ret = kvm_s2_handle_perm_fault(vcpu, &nested_trans);
                if (ret) {
                        esr = kvm_s2_trans_esr(&nested_trans);
                        kvm_inject_s2_fault(vcpu, esr);
                        goto out_unlock;
                }

                ipa = kvm_s2_trans_output(&nested_trans);
                nested = &nested_trans;
        }

        gfn = ipa >> PAGE_SHIFT;
        memslot = gfn_to_memslot(vcpu->kvm, gfn);
        hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);
        write_fault = kvm_is_write_fault(vcpu);
        if (kvm_is_error_hva(hva) || (write_fault && !writable)) {
                /*
                 * The guest has put either its instructions or its page-tables
                 * somewhere it shouldn't have. Userspace won't be able to do
                 * anything about this (there's no syndrome for a start), so
                 * re-inject the abort back into the guest.
                 */
                if (is_iabt) {
                        ret = -ENOEXEC;
                        goto out;
                }

                if (kvm_vcpu_abt_iss1tw(vcpu)) {
                        ret = kvm_inject_sea_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
                        goto out_unlock;
                }

                /*
                 * Check for a cache maintenance operation. Since we
                 * ended-up here, we know it is outside of any memory
                 * slot. But we can't find out if that is for a device,
                 * or if the guest is just being stupid. The only thing
                 * we know for sure is that this range cannot be cached.
                 *
                 * So let's assume that the guest is just being
                 * cautious, and skip the instruction.
                 */
                if (kvm_is_error_hva(hva) && kvm_vcpu_dabt_is_cm(vcpu)) {
                        kvm_incr_pc(vcpu);
                        ret = 1;
                        goto out_unlock;
                }

                /*
                 * The IPA is reported as [MAX:12], so we need to
                 * complement it with the bottom 12 bits from the
                 * faulting VA. This is always 12 bits, irrespective
                 * of the page size.
                 */
                ipa |= FAR_TO_FIPA_OFFSET(kvm_vcpu_get_hfar(vcpu));
                ret = io_mem_abort(vcpu, ipa);
                goto out_unlock;
        }

        /* Userspace should not be able to register out-of-bounds IPAs */
        VM_BUG_ON(ipa >= kvm_phys_size(vcpu->arch.hw_mmu));

        if (esr_fsc_is_access_flag_fault(esr)) {
                handle_access_fault(vcpu, fault_ipa);
                ret = 1;
                goto out_unlock;
        }

        const struct kvm_s2_fault_desc s2fd = {
                .vcpu           = vcpu,
                .fault_ipa      = fault_ipa,
                .nested         = nested,
                .memslot        = memslot,
                .hva            = hva,
        };

        if (kvm_vm_is_protected(vcpu->kvm)) {
                ret = pkvm_mem_abort(&s2fd);
        } else {
                VM_WARN_ON_ONCE(kvm_vcpu_trap_is_permission_fault(vcpu) &&
                                !write_fault &&
                                !kvm_vcpu_trap_is_exec_fault(vcpu));

                if (kvm_slot_has_gmem(memslot))
                        ret = gmem_abort(&s2fd);
                else
                        ret = user_mem_abort(&s2fd);
        }

        if (ret == 0)
                ret = 1;
out:
        if (ret == -ENOEXEC)
                ret = kvm_inject_sea_iabt(vcpu, kvm_vcpu_get_hfar(vcpu));
out_unlock:
        srcu_read_unlock(&vcpu->kvm->srcu, idx);
        return ret;
}

bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
{
        if (!kvm->arch.mmu.pgt || kvm_vm_is_protected(kvm))
                return false;

        __unmap_stage2_range(&kvm->arch.mmu, range->start << PAGE_SHIFT,
                             (range->end - range->start) << PAGE_SHIFT,
                             range->may_block);

        kvm_nested_s2_unmap(kvm, range->may_block);
        return false;
}

bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
{
        u64 size = (range->end - range->start) << PAGE_SHIFT;

        if (!kvm->arch.mmu.pgt || kvm_vm_is_protected(kvm))
                return false;

        return KVM_PGT_FN(kvm_pgtable_stage2_test_clear_young)(kvm->arch.mmu.pgt,
                                                   range->start << PAGE_SHIFT,
                                                   size, true);
        /*
         * TODO: Handle nested_mmu structures here using the reverse mapping in
         * a later version of patch series.
         */
}

bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
{
        u64 size = (range->end - range->start) << PAGE_SHIFT;

        if (!kvm->arch.mmu.pgt || kvm_vm_is_protected(kvm))
                return false;

        return KVM_PGT_FN(kvm_pgtable_stage2_test_clear_young)(kvm->arch.mmu.pgt,
                                                   range->start << PAGE_SHIFT,
                                                   size, false);
}

phys_addr_t kvm_mmu_get_httbr(void)
{
        return __pa(hyp_pgtable->pgd);
}

phys_addr_t kvm_get_idmap_vector(void)
{
        return hyp_idmap_vector;
}

static int kvm_map_idmap_text(void)
{
        unsigned long size = hyp_idmap_end - hyp_idmap_start;
        int err = __create_hyp_mappings(hyp_idmap_start, size, hyp_idmap_start,
                                        PAGE_HYP_EXEC);
        if (err)
                kvm_err("Failed to idmap %lx-%lx\n",
                        hyp_idmap_start, hyp_idmap_end);

        return err;
}

static void *kvm_hyp_zalloc_page(void *arg)
{
        return (void *)get_zeroed_page(GFP_KERNEL);
}

static struct kvm_pgtable_mm_ops kvm_hyp_mm_ops = {
        .zalloc_page            = kvm_hyp_zalloc_page,
        .get_page               = kvm_host_get_page,
        .put_page               = kvm_host_put_page,
        .phys_to_virt           = kvm_host_va,
        .virt_to_phys           = kvm_host_pa,
};

int __init kvm_mmu_init(u32 hyp_va_bits)
{
        int err;

        hyp_idmap_start = __pa_symbol(__hyp_idmap_text_start);
        hyp_idmap_start = ALIGN_DOWN(hyp_idmap_start, PAGE_SIZE);
        hyp_idmap_end = __pa_symbol(__hyp_idmap_text_end);
        hyp_idmap_end = ALIGN(hyp_idmap_end, PAGE_SIZE);
        hyp_idmap_vector = __pa_symbol(__kvm_hyp_init);

        /*
         * We rely on the linker script to ensure at build time that the HYP
         * init code does not cross a page boundary.
         */
        BUG_ON((hyp_idmap_start ^ (hyp_idmap_end - 1)) & PAGE_MASK);

        kvm_debug("Using %u-bit virtual addresses at EL2\n", hyp_va_bits);
        kvm_debug("IDMAP page: %lx\n", hyp_idmap_start);
        kvm_debug("HYP VA range: %lx:%lx\n",
                  kern_hyp_va(PAGE_OFFSET),
                  kern_hyp_va((unsigned long)high_memory - 1));

        if (hyp_idmap_start >= kern_hyp_va(PAGE_OFFSET) &&
            hyp_idmap_start <  kern_hyp_va((unsigned long)high_memory - 1) &&
            hyp_idmap_start != (unsigned long)__hyp_idmap_text_start) {
                /*
                 * The idmap page is intersecting with the VA space,
                 * it is not safe to continue further.
                 */
                kvm_err("IDMAP intersecting with HYP VA, unable to continue\n");
                err = -EINVAL;
                goto out;
        }

        hyp_pgtable = kzalloc_obj(*hyp_pgtable);
        if (!hyp_pgtable) {
                kvm_err("Hyp mode page-table not allocated\n");
                err = -ENOMEM;
                goto out;
        }

        err = kvm_pgtable_hyp_init(hyp_pgtable, hyp_va_bits, &kvm_hyp_mm_ops);
        if (err)
                goto out_free_pgtable;

        err = kvm_map_idmap_text();
        if (err)
                goto out_destroy_pgtable;

        io_map_base = hyp_idmap_start;
        __hyp_va_bits = hyp_va_bits;
        return 0;

out_destroy_pgtable:
        kvm_pgtable_hyp_destroy(hyp_pgtable);
out_free_pgtable:
        kfree(hyp_pgtable);
        hyp_pgtable = NULL;
out:
        return err;
}

void kvm_arch_commit_memory_region(struct kvm *kvm,
                                   struct kvm_memory_slot *old,
                                   const struct kvm_memory_slot *new,
                                   enum kvm_mr_change change)
{
        bool log_dirty_pages = new && new->flags & KVM_MEM_LOG_DIRTY_PAGES;

        /*
         * At this point memslot has been committed and there is an
         * allocated dirty_bitmap[], dirty pages will be tracked while the
         * memory slot is write protected.
         */
        if (log_dirty_pages) {

                if (change == KVM_MR_DELETE)
                        return;

                /*
                 * Huge and normal pages are write-protected and split
                 * on either of these two cases:
                 *
                 * 1. with initial-all-set: gradually with CLEAR ioctls,
                 */
                if (kvm_dirty_log_manual_protect_and_init_set(kvm))
                        return;
                /*
                 * or
                 * 2. without initial-all-set: all in one shot when
                 *    enabling dirty logging.
                 */
                kvm_mmu_wp_memory_region(kvm, new->id);
                kvm_mmu_split_memory_region(kvm, new->id);
        } else {
                /*
                 * Free any leftovers from the eager page splitting cache. Do
                 * this when deleting, moving, disabling dirty logging, or
                 * creating the memslot (a nop). Doing it for deletes makes
                 * sure we don't leak memory, and there's no need to keep the
                 * cache around for any of the other cases.
                 */
                kvm_mmu_free_memory_cache(&kvm->arch.mmu.split_page_cache);
        }
}

int kvm_arch_prepare_memory_region(struct kvm *kvm,
                                   const struct kvm_memory_slot *old,
                                   struct kvm_memory_slot *new,
                                   enum kvm_mr_change change)
{
        hva_t hva, reg_end;
        int ret = 0;

        if (kvm_vm_is_protected(kvm)) {
                /* Cannot modify memslots once a pVM has run. */
                if (pkvm_hyp_vm_is_created(kvm) &&
                    (change == KVM_MR_DELETE || change == KVM_MR_MOVE)) {
                        return -EPERM;
                }

                if (new &&
                    new->flags & (KVM_MEM_LOG_DIRTY_PAGES | KVM_MEM_READONLY)) {
                        return -EPERM;
                }
        }

        if (change != KVM_MR_CREATE && change != KVM_MR_MOVE &&
                        change != KVM_MR_FLAGS_ONLY)
                return 0;

        /*
         * Prevent userspace from creating a memory region outside of the IPA
         * space addressable by the KVM guest IPA space.
         */
        if ((new->base_gfn + new->npages) > (kvm_phys_size(&kvm->arch.mmu) >> PAGE_SHIFT))
                return -EFAULT;

        /*
         * Only support guest_memfd backed memslots with mappable memory, since
         * there aren't any CoCo VMs that support only private memory on arm64.
         */
        if (kvm_slot_has_gmem(new) && !kvm_memslot_is_gmem_only(new))
                return -EINVAL;

        /* guest_memfd is incompatible with MTE. */
        if (kvm_slot_has_gmem(new) && kvm_has_mte(kvm))
                return -EINVAL;

        hva = new->userspace_addr;
        reg_end = hva + (new->npages << PAGE_SHIFT);

        mmap_read_lock(current->mm);
        /*
         * A memory region could potentially cover multiple VMAs, and any holes
         * between them, so iterate over all of them.
         *
         *     +--------------------------------------------+
         * +---------------+----------------+   +----------------+
         * |   : VMA 1     |      VMA 2     |   |    VMA 3  :    |
         * +---------------+----------------+   +----------------+
         *     |               memory region                |
         *     +--------------------------------------------+
         */
        do {
                struct vm_area_struct *vma;

                vma = find_vma_intersection(current->mm, hva, reg_end);
                if (!vma)
                        break;

                if (kvm_has_mte(kvm) && !kvm_vma_mte_allowed(vma)) {
                        ret = -EINVAL;
                        break;
                }

                if (vma->vm_flags & VM_PFNMAP) {
                        /* IO region dirty page logging not allowed */
                        if (new->flags & KVM_MEM_LOG_DIRTY_PAGES) {
                                ret = -EINVAL;
                                break;
                        }

                        /*
                         * Cacheable PFNMAP is allowed only if the hardware
                         * supports it.
                         */
                        if (kvm_vma_is_cacheable(vma) && !kvm_supports_cacheable_pfnmap()) {
                                ret = -EINVAL;
                                break;
                        }
                }
                hva = min(reg_end, vma->vm_end);
        } while (hva < reg_end);

        mmap_read_unlock(current->mm);
        return ret;
}

void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot)
{
}

void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen)
{
}

void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
                                   struct kvm_memory_slot *slot)
{
        gpa_t gpa = slot->base_gfn << PAGE_SHIFT;
        phys_addr_t size = slot->npages << PAGE_SHIFT;

        write_lock(&kvm->mmu_lock);
        kvm_stage2_unmap_range(&kvm->arch.mmu, gpa, size, true);
        kvm_nested_s2_unmap(kvm, true);
        write_unlock(&kvm->mmu_lock);
}

/*
 * See note at ARMv7 ARM B1.14.4 (TL;DR: S/W ops are not easily virtualized).
 *
 * Main problems:
 * - S/W ops are local to a CPU (not broadcast)
 * - We have line migration behind our back (speculation)
 * - System caches don't support S/W at all (damn!)
 *
 * In the face of the above, the best we can do is to try and convert
 * S/W ops to VA ops. Because the guest is not allowed to infer the
 * S/W to PA mapping, it can only use S/W to nuke the whole cache,
 * which is a rather good thing for us.
 *
 * Also, it is only used when turning caches on/off ("The expected
 * usage of the cache maintenance instructions that operate by set/way
 * is associated with the cache maintenance instructions associated
 * with the powerdown and powerup of caches, if this is required by
 * the implementation.").
 *
 * We use the following policy:
 *
 * - If we trap a S/W operation, we enable VM trapping to detect
 *   caches being turned on/off, and do a full clean.
 *
 * - We flush the caches on both caches being turned on and off.
 *
 * - Once the caches are enabled, we stop trapping VM ops.
 */
void kvm_set_way_flush(struct kvm_vcpu *vcpu)
{
        unsigned long hcr = *vcpu_hcr(vcpu);

        /*
         * If this is the first time we do a S/W operation
         * (i.e. HCR_TVM not set) flush the whole memory, and set the
         * VM trapping.
         *
         * Otherwise, rely on the VM trapping to wait for the MMU +
         * Caches to be turned off. At that point, we'll be able to
         * clean the caches again.
         */
        if (!(hcr & HCR_TVM)) {
                trace_kvm_set_way_flush(*vcpu_pc(vcpu),
                                        vcpu_has_cache_enabled(vcpu));
                stage2_flush_vm(vcpu->kvm);
                *vcpu_hcr(vcpu) = hcr | HCR_TVM;
        }
}

void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled)
{
        bool now_enabled = vcpu_has_cache_enabled(vcpu);

        /*
         * If switching the MMU+caches on, need to invalidate the caches.
         * If switching it off, need to clean the caches.
         * Clean + invalidate does the trick always.
         */
        if (now_enabled != was_enabled)
                stage2_flush_vm(vcpu->kvm);

        /* Caches are now on, stop trapping VM ops (until a S/W op) */
        if (now_enabled)
                *vcpu_hcr(vcpu) &= ~HCR_TVM;

        trace_kvm_toggle_cache(*vcpu_pc(vcpu), was_enabled, now_enabled);
}