// SPDX-License-Identifier: GPL-2.0+
/*
 * Secure VM platform
 *
 * Copyright 2018 IBM Corporation
 * Author: Anshuman Khandual <khandual@linux.vnet.ibm.com>
 */

#include <linux/mm.h>
#include <linux/memblock.h>
#include <linux/mem_encrypt.h>
#include <linux/cc_platform.h>
#include <asm/machdep.h>
#include <asm/svm.h>
#include <asm/swiotlb.h>
#include <asm/ultravisor.h>
#include <asm/dtl.h>

static int __init init_svm(void)
{
        if (!is_secure_guest())
                return 0;

        /* Don't release the SWIOTLB buffer. */
        ppc_swiotlb_enable = 1;

        /*
         * Since the guest memory is inaccessible to the host, devices always
         * need to use the SWIOTLB buffer for DMA even if dma_capable() says
         * otherwise.
         */
        ppc_swiotlb_flags |= SWIOTLB_ANY | SWIOTLB_FORCE;

        /* Share the SWIOTLB buffer with the host. */
        swiotlb_update_mem_attributes();

        return 0;
}
machine_early_initcall(pseries, init_svm);

int set_memory_encrypted(unsigned long addr, int numpages)
{
        if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
                return 0;

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

        uv_unshare_page(PHYS_PFN(__pa(addr)), numpages);

        return 0;
}

int set_memory_decrypted(unsigned long addr, int numpages)
{
        if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
                return 0;

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

        uv_share_page(PHYS_PFN(__pa(addr)), numpages);

        return 0;
}

/* There's one dispatch log per CPU. */
#define NR_DTL_PAGE (DISPATCH_LOG_BYTES * CONFIG_NR_CPUS / PAGE_SIZE)

static struct page *dtl_page_store[NR_DTL_PAGE];
static long dtl_nr_pages;

static bool is_dtl_page_shared(struct page *page)
{
        long i;

        for (i = 0; i < dtl_nr_pages; i++)
                if (dtl_page_store[i] == page)
                        return true;

        return false;
}

void dtl_cache_ctor(void *addr)
{
        unsigned long pfn = PHYS_PFN(__pa(addr));
        struct page *page = pfn_to_page(pfn);

        if (!is_dtl_page_shared(page)) {
                dtl_page_store[dtl_nr_pages] = page;
                dtl_nr_pages++;
                WARN_ON(dtl_nr_pages >= NR_DTL_PAGE);
                uv_share_page(pfn, 1);
        }
}