// SPDX-License-Identifier: GPL-2.0
#include <linux/acpi.h>
#include <linux/cpufreq.h>
#include <linux/cpuidle.h>
#include <linux/export.h>
#include <linux/mm.h>

#include <xen/hvc-console.h>
#include <xen/acpi.h>

#include <asm/bootparam.h>
#include <asm/io_apic.h>
#include <asm/hypervisor.h>
#include <asm/e820/api.h>
#include <asm/setup.h>

#include <xen/xen.h>
#include <asm/xen/interface.h>
#include <asm/xen/hypercall.h>

#include <xen/interface/memory.h>

#include "xen-ops.h"

/*
 * PVH variables.
 *
 * The variable xen_pvh needs to live in a data segment since it is used
 * after startup_{32|64} is invoked, which will clear the .bss segment.
 */
bool __ro_after_init xen_pvh;
EXPORT_SYMBOL_GPL(xen_pvh);

#ifdef CONFIG_XEN_DOM0
int xen_pvh_setup_gsi(int gsi, int trigger, int polarity)
{
        int ret;
        struct physdev_setup_gsi setup_gsi;

        setup_gsi.gsi = gsi;
        setup_gsi.triggering = (trigger == ACPI_EDGE_SENSITIVE ? 0 : 1);
        setup_gsi.polarity = (polarity == ACPI_ACTIVE_HIGH ? 0 : 1);

        ret = HYPERVISOR_physdev_op(PHYSDEVOP_setup_gsi, &setup_gsi);
        if (ret == -EEXIST) {
                xen_raw_printk("Already setup the GSI :%d\n", gsi);
                ret = 0;
        } else if (ret)
                xen_raw_printk("Fail to setup GSI (%d)!\n", gsi);

        return ret;
}
EXPORT_SYMBOL_GPL(xen_pvh_setup_gsi);
#endif

/*
 * Reserve e820 UNUSABLE regions to inflate the memory balloon.
 *
 * On PVH dom0 the host memory map is used, RAM regions available to dom0 are
 * located as the same place as in the native memory map, but since dom0 gets
 * less memory than the total amount of host RAM the ranges that can't be
 * populated are converted from RAM -> UNUSABLE.  Use such regions (up to the
 * ratio signaled in EXTRA_MEM_RATIO) in order to inflate the balloon driver at
 * boot.  Doing so prevents the guest (even if just temporary) from using holes
 * in the memory map in order to map grants or foreign addresses, and
 * hopefully limits the risk of a clash with a device MMIO region.  Ideally the
 * hypervisor should notify us which memory ranges are suitable for creating
 * foreign mappings, but that's not yet implemented.
 */
static void __init pvh_reserve_extra_memory(void)
{
        struct boot_params *bootp = &boot_params;
        unsigned int i, ram_pages = 0, extra_pages;

        for (i = 0; i < bootp->e820_entries; i++) {
                struct boot_e820_entry *e = &bootp->e820_table[i];

                if (e->type != E820_TYPE_RAM)
                        continue;
                ram_pages += PFN_DOWN(e->addr + e->size) - PFN_UP(e->addr);
        }

        /* Max amount of extra memory. */
        extra_pages = EXTRA_MEM_RATIO * ram_pages;

        /*
         * Convert UNUSABLE ranges to RAM and reserve them for foreign mapping
         * purposes.
         */
        for (i = 0; i < bootp->e820_entries && extra_pages; i++) {
                struct boot_e820_entry *e = &bootp->e820_table[i];
                unsigned long pages;

                if (e->type != E820_TYPE_UNUSABLE)
                        continue;

                pages = min(extra_pages,
                        PFN_DOWN(e->addr + e->size) - PFN_UP(e->addr));

                if (pages != (PFN_DOWN(e->addr + e->size) - PFN_UP(e->addr))) {
                        struct boot_e820_entry *next;

                        if (bootp->e820_entries ==
                            ARRAY_SIZE(bootp->e820_table))
                                /* No space left to split - skip region. */
                                continue;

                        /* Split entry. */
                        next = e + 1;
                        memmove(next, e,
                                (bootp->e820_entries - i) * sizeof(*e));
                        bootp->e820_entries++;
                        next->addr = PAGE_ALIGN(e->addr) + PFN_PHYS(pages);
                        e->size = next->addr - e->addr;
                        next->size -= e->size;
                }
                e->type = E820_TYPE_RAM;
                extra_pages -= pages;

                xen_add_extra_mem(PFN_UP(e->addr), pages);
        }
}

static void __init pvh_arch_setup(void)
{
        pvh_reserve_extra_memory();

        if (xen_initial_domain()) {
                xen_add_preferred_consoles();

                /*
                 * Disable usage of CPU idle and frequency drivers: when
                 * running as hardware domain the exposed native ACPI tables
                 * causes idle and/or frequency drivers to attach and
                 * malfunction.  It's Xen the entity that controls the idle and
                 * frequency states.
                 *
                 * For unprivileged domains the exposed ACPI tables are
                 * fabricated and don't contain such data.
                 */
                disable_cpuidle();
                disable_cpufreq();
                WARN_ON(xen_set_default_idle());
        }
}

void __init xen_pvh_init(struct boot_params *boot_params)
{
        xen_pvh = 1;
        xen_domain_type = XEN_HVM_DOMAIN;
        xen_start_flags = pvh_start_info.flags;

        x86_init.oem.arch_setup = pvh_arch_setup;
        x86_init.oem.banner = xen_banner;

        xen_efi_init(boot_params);

        if (xen_initial_domain()) {
                struct xen_platform_op op = {
                        .cmd = XENPF_get_dom0_console,
                };
                int ret = HYPERVISOR_platform_op(&op);

                if (ret > 0)
                        xen_init_vga(&op.u.dom0_console,
                                     min(ret * sizeof(char),
                                         sizeof(op.u.dom0_console)),
                                     &boot_params->screen_info);
        }
}

void __init mem_map_via_hcall(struct boot_params *boot_params_p)
{
        struct xen_memory_map memmap;
        int rc;

        memmap.nr_entries = ARRAY_SIZE(boot_params_p->e820_table);
        set_xen_guest_handle(memmap.buffer, boot_params_p->e820_table);
        rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
        if (rc) {
                xen_raw_printk("XENMEM_memory_map failed (%d)\n", rc);
                BUG();
        }
        boot_params_p->e820_entries = memmap.nr_entries;
}