/*
 * GTT virtualization
 *
 * Copyright(c) 2011-2016 Intel Corporation. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * Authors:
 *    Zhi Wang <zhi.a.wang@intel.com>
 *    Zhenyu Wang <zhenyuw@linux.intel.com>
 *    Xiao Zheng <xiao.zheng@intel.com>
 *
 * Contributors:
 *    Min He <min.he@intel.com>
 *    Bing Niu <bing.niu@intel.com>
 *
 */

#include "i915_drv.h"
#include "gvt.h"
#include "i915_pvinfo.h"
#include "trace.h"

static bool enable_out_of_sync = false;
static int preallocated_oos_pages = 8192;

/*
 * validate a gm address and related range size,
 * translate it to host gm address
 */
bool intel_gvt_ggtt_validate_range(struct intel_vgpu *vgpu, u64 addr, u32 size)
{
        if ((!vgpu_gmadr_is_valid(vgpu, addr)) || (size
                        && !vgpu_gmadr_is_valid(vgpu, addr + size - 1))) {
                gvt_vgpu_err("invalid range gmadr 0x%llx size 0x%x\n",
                                addr, size);
                return false;
        }
        return true;
}

/* translate a guest gmadr to host gmadr */
int intel_gvt_ggtt_gmadr_g2h(struct intel_vgpu *vgpu, u64 g_addr, u64 *h_addr)
{
        if (WARN(!vgpu_gmadr_is_valid(vgpu, g_addr),
                 "invalid guest gmadr %llx\n", g_addr))
                return -EACCES;

        if (vgpu_gmadr_is_aperture(vgpu, g_addr))
                *h_addr = vgpu_aperture_gmadr_base(vgpu)
                          + (g_addr - vgpu_aperture_offset(vgpu));
        else
                *h_addr = vgpu_hidden_gmadr_base(vgpu)
                          + (g_addr - vgpu_hidden_offset(vgpu));
        return 0;
}

/* translate a host gmadr to guest gmadr */
int intel_gvt_ggtt_gmadr_h2g(struct intel_vgpu *vgpu, u64 h_addr, u64 *g_addr)
{
        if (WARN(!gvt_gmadr_is_valid(vgpu->gvt, h_addr),
                 "invalid host gmadr %llx\n", h_addr))
                return -EACCES;

        if (gvt_gmadr_is_aperture(vgpu->gvt, h_addr))
                *g_addr = vgpu_aperture_gmadr_base(vgpu)
                        + (h_addr - gvt_aperture_gmadr_base(vgpu->gvt));
        else
                *g_addr = vgpu_hidden_gmadr_base(vgpu)
                        + (h_addr - gvt_hidden_gmadr_base(vgpu->gvt));
        return 0;
}

int intel_gvt_ggtt_index_g2h(struct intel_vgpu *vgpu, unsigned long g_index,
                             unsigned long *h_index)
{
        u64 h_addr;
        int ret;

        ret = intel_gvt_ggtt_gmadr_g2h(vgpu, g_index << I915_GTT_PAGE_SHIFT,
                                       &h_addr);
        if (ret)
                return ret;

        *h_index = h_addr >> I915_GTT_PAGE_SHIFT;
        return 0;
}

int intel_gvt_ggtt_h2g_index(struct intel_vgpu *vgpu, unsigned long h_index,
                             unsigned long *g_index)
{
        u64 g_addr;
        int ret;

        ret = intel_gvt_ggtt_gmadr_h2g(vgpu, h_index << I915_GTT_PAGE_SHIFT,
                                       &g_addr);
        if (ret)
                return ret;

        *g_index = g_addr >> I915_GTT_PAGE_SHIFT;
        return 0;
}

#define gtt_type_is_entry(type) \
        (type > GTT_TYPE_INVALID && type < GTT_TYPE_PPGTT_ENTRY \
         && type != GTT_TYPE_PPGTT_PTE_ENTRY \
         && type != GTT_TYPE_PPGTT_ROOT_ENTRY)

#define gtt_type_is_pt(type) \
        (type >= GTT_TYPE_PPGTT_PTE_PT && type < GTT_TYPE_MAX)

#define gtt_type_is_pte_pt(type) \
        (type == GTT_TYPE_PPGTT_PTE_PT)

#define gtt_type_is_root_pointer(type) \
        (gtt_type_is_entry(type) && type > GTT_TYPE_PPGTT_ROOT_ENTRY)

#define gtt_init_entry(e, t, p, v) do { \
        (e)->type = t; \
        (e)->pdev = p; \
        memcpy(&(e)->val64, &v, sizeof(v)); \
} while (0)

/*
 * Mappings between GTT_TYPE* enumerations.
 * Following information can be found according to the given type:
 * - type of next level page table
 * - type of entry inside this level page table
 * - type of entry with PSE set
 *
 * If the given type doesn't have such a kind of information,
 * e.g. give a l4 root entry type, then request to get its PSE type,
 * give a PTE page table type, then request to get its next level page
 * table type, as we know l4 root entry doesn't have a PSE bit,
 * and a PTE page table doesn't have a next level page table type,
 * GTT_TYPE_INVALID will be returned. This is useful when traversing a
 * page table.
 */

struct gtt_type_table_entry {
        int entry_type;
        int pt_type;
        int next_pt_type;
        int pse_entry_type;
};

#define GTT_TYPE_TABLE_ENTRY(type, e_type, cpt_type, npt_type, pse_type) \
        [type] = { \
                .entry_type = e_type, \
                .pt_type = cpt_type, \
                .next_pt_type = npt_type, \
                .pse_entry_type = pse_type, \
        }

static struct gtt_type_table_entry gtt_type_table[] = {
        GTT_TYPE_TABLE_ENTRY(GTT_TYPE_PPGTT_ROOT_L4_ENTRY,
                        GTT_TYPE_PPGTT_ROOT_L4_ENTRY,
                        GTT_TYPE_INVALID,
                        GTT_TYPE_PPGTT_PML4_PT,
                        GTT_TYPE_INVALID),
        GTT_TYPE_TABLE_ENTRY(GTT_TYPE_PPGTT_PML4_PT,
                        GTT_TYPE_PPGTT_PML4_ENTRY,
                        GTT_TYPE_PPGTT_PML4_PT,
                        GTT_TYPE_PPGTT_PDP_PT,
                        GTT_TYPE_INVALID),
        GTT_TYPE_TABLE_ENTRY(GTT_TYPE_PPGTT_PML4_ENTRY,
                        GTT_TYPE_PPGTT_PML4_ENTRY,
                        GTT_TYPE_PPGTT_PML4_PT,
                        GTT_TYPE_PPGTT_PDP_PT,
                        GTT_TYPE_INVALID),
        GTT_TYPE_TABLE_ENTRY(GTT_TYPE_PPGTT_PDP_PT,
                        GTT_TYPE_PPGTT_PDP_ENTRY,
                        GTT_TYPE_PPGTT_PDP_PT,
                        GTT_TYPE_PPGTT_PDE_PT,
                        GTT_TYPE_PPGTT_PTE_1G_ENTRY),
        GTT_TYPE_TABLE_ENTRY(GTT_TYPE_PPGTT_ROOT_L3_ENTRY,
                        GTT_TYPE_PPGTT_ROOT_L3_ENTRY,
                        GTT_TYPE_INVALID,
                        GTT_TYPE_PPGTT_PDE_PT,
                        GTT_TYPE_PPGTT_PTE_1G_ENTRY),
        GTT_TYPE_TABLE_ENTRY(GTT_TYPE_PPGTT_PDP_ENTRY,
                        GTT_TYPE_PPGTT_PDP_ENTRY,
                        GTT_TYPE_PPGTT_PDP_PT,
                        GTT_TYPE_PPGTT_PDE_PT,
                        GTT_TYPE_PPGTT_PTE_1G_ENTRY),
        GTT_TYPE_TABLE_ENTRY(GTT_TYPE_PPGTT_PDE_PT,
                        GTT_TYPE_PPGTT_PDE_ENTRY,
                        GTT_TYPE_PPGTT_PDE_PT,
                        GTT_TYPE_PPGTT_PTE_PT,
                        GTT_TYPE_PPGTT_PTE_2M_ENTRY),
        GTT_TYPE_TABLE_ENTRY(GTT_TYPE_PPGTT_PDE_ENTRY,
                        GTT_TYPE_PPGTT_PDE_ENTRY,
                        GTT_TYPE_PPGTT_PDE_PT,
                        GTT_TYPE_PPGTT_PTE_PT,
                        GTT_TYPE_PPGTT_PTE_2M_ENTRY),
        GTT_TYPE_TABLE_ENTRY(GTT_TYPE_PPGTT_PTE_PT,
                        GTT_TYPE_PPGTT_PTE_4K_ENTRY,
                        GTT_TYPE_PPGTT_PTE_PT,
                        GTT_TYPE_INVALID,
                        GTT_TYPE_INVALID),
        GTT_TYPE_TABLE_ENTRY(GTT_TYPE_PPGTT_PTE_4K_ENTRY,
                        GTT_TYPE_PPGTT_PTE_4K_ENTRY,
                        GTT_TYPE_PPGTT_PTE_PT,
                        GTT_TYPE_INVALID,
                        GTT_TYPE_INVALID),
        GTT_TYPE_TABLE_ENTRY(GTT_TYPE_PPGTT_PTE_2M_ENTRY,
                        GTT_TYPE_PPGTT_PDE_ENTRY,
                        GTT_TYPE_PPGTT_PDE_PT,
                        GTT_TYPE_INVALID,
                        GTT_TYPE_PPGTT_PTE_2M_ENTRY),
        GTT_TYPE_TABLE_ENTRY(GTT_TYPE_PPGTT_PTE_1G_ENTRY,
                        GTT_TYPE_PPGTT_PDP_ENTRY,
                        GTT_TYPE_PPGTT_PDP_PT,
                        GTT_TYPE_INVALID,
                        GTT_TYPE_PPGTT_PTE_1G_ENTRY),
        GTT_TYPE_TABLE_ENTRY(GTT_TYPE_GGTT_PTE,
                        GTT_TYPE_GGTT_PTE,
                        GTT_TYPE_INVALID,
                        GTT_TYPE_INVALID,
                        GTT_TYPE_INVALID),
};

static inline int get_next_pt_type(int type)
{
        return gtt_type_table[type].next_pt_type;
}

static inline int get_pt_type(int type)
{
        return gtt_type_table[type].pt_type;
}

static inline int get_entry_type(int type)
{
        return gtt_type_table[type].entry_type;
}

static inline int get_pse_type(int type)
{
        return gtt_type_table[type].pse_entry_type;
}

static u64 read_pte64(struct drm_i915_private *dev_priv, unsigned long index)
{
        void __iomem *addr = (gen8_pte_t __iomem *)dev_priv->ggtt.gsm + index;

        return readq(addr);
}

static void gtt_invalidate(struct drm_i915_private *dev_priv)
{
        mmio_hw_access_pre(dev_priv);
        I915_WRITE(GFX_FLSH_CNTL_GEN6, GFX_FLSH_CNTL_EN);
        mmio_hw_access_post(dev_priv);
}

static void write_pte64(struct drm_i915_private *dev_priv,
                unsigned long index, u64 pte)
{
        void __iomem *addr = (gen8_pte_t __iomem *)dev_priv->ggtt.gsm + index;

        writeq(pte, addr);
}

static inline int gtt_get_entry64(void *pt,
                struct intel_gvt_gtt_entry *e,
                unsigned long index, bool hypervisor_access, unsigned long gpa,
                struct intel_vgpu *vgpu)
{
        const struct intel_gvt_device_info *info = &vgpu->gvt->device_info;
        int ret;

        if (WARN_ON(info->gtt_entry_size != 8))
                return -EINVAL;

        if (hypervisor_access) {
                ret = intel_gvt_hypervisor_read_gpa(vgpu, gpa +
                                (index << info->gtt_entry_size_shift),
                                &e->val64, 8);
                if (WARN_ON(ret))
                        return ret;
        } else if (!pt) {
                e->val64 = read_pte64(vgpu->gvt->dev_priv, index);
        } else {
                e->val64 = *((u64 *)pt + index);
        }
        return 0;
}

static inline int gtt_set_entry64(void *pt,
                struct intel_gvt_gtt_entry *e,
                unsigned long index, bool hypervisor_access, unsigned long gpa,
                struct intel_vgpu *vgpu)
{
        const struct intel_gvt_device_info *info = &vgpu->gvt->device_info;
        int ret;

        if (WARN_ON(info->gtt_entry_size != 8))
                return -EINVAL;

        if (hypervisor_access) {
                ret = intel_gvt_hypervisor_write_gpa(vgpu, gpa +
                                (index << info->gtt_entry_size_shift),
                                &e->val64, 8);
                if (WARN_ON(ret))
                        return ret;
        } else if (!pt) {
                write_pte64(vgpu->gvt->dev_priv, index, e->val64);
        } else {
                *((u64 *)pt + index) = e->val64;
        }
        return 0;
}

#define GTT_HAW 46

#define ADDR_1G_MASK (((1UL << (GTT_HAW - 30)) - 1) << 30)
#define ADDR_2M_MASK (((1UL << (GTT_HAW - 21)) - 1) << 21)
#define ADDR_4K_MASK (((1UL << (GTT_HAW - 12)) - 1) << 12)

static unsigned long gen8_gtt_get_pfn(struct intel_gvt_gtt_entry *e)
{
        unsigned long pfn;

        if (e->type == GTT_TYPE_PPGTT_PTE_1G_ENTRY)
                pfn = (e->val64 & ADDR_1G_MASK) >> 12;
        else if (e->type == GTT_TYPE_PPGTT_PTE_2M_ENTRY)
                pfn = (e->val64 & ADDR_2M_MASK) >> 12;
        else
                pfn = (e->val64 & ADDR_4K_MASK) >> 12;
        return pfn;
}

static void gen8_gtt_set_pfn(struct intel_gvt_gtt_entry *e, unsigned long pfn)
{
        if (e->type == GTT_TYPE_PPGTT_PTE_1G_ENTRY) {
                e->val64 &= ~ADDR_1G_MASK;
                pfn &= (ADDR_1G_MASK >> 12);
        } else if (e->type == GTT_TYPE_PPGTT_PTE_2M_ENTRY) {
                e->val64 &= ~ADDR_2M_MASK;
                pfn &= (ADDR_2M_MASK >> 12);
        } else {
                e->val64 &= ~ADDR_4K_MASK;
                pfn &= (ADDR_4K_MASK >> 12);
        }

        e->val64 |= (pfn << 12);
}

static bool gen8_gtt_test_pse(struct intel_gvt_gtt_entry *e)
{
        /* Entry doesn't have PSE bit. */
        if (get_pse_type(e->type) == GTT_TYPE_INVALID)
                return false;

        e->type = get_entry_type(e->type);
        if (!(e->val64 & BIT(7)))
                return false;

        e->type = get_pse_type(e->type);
        return true;
}

static bool gen8_gtt_test_present(struct intel_gvt_gtt_entry *e)
{
        /*
         * i915 writes PDP root pointer registers without present bit,
         * it also works, so we need to treat root pointer entry
         * specifically.
         */
        if (e->type == GTT_TYPE_PPGTT_ROOT_L3_ENTRY
                        || e->type == GTT_TYPE_PPGTT_ROOT_L4_ENTRY)
                return (e->val64 != 0);
        else
                return (e->val64 & BIT(0));
}

static void gtt_entry_clear_present(struct intel_gvt_gtt_entry *e)
{
        e->val64 &= ~BIT(0);
}

static void gtt_entry_set_present(struct intel_gvt_gtt_entry *e)
{
        e->val64 |= BIT(0);
}

/*
 * Per-platform GMA routines.
 */
static unsigned long gma_to_ggtt_pte_index(unsigned long gma)
{
        unsigned long x = (gma >> I915_GTT_PAGE_SHIFT);

        trace_gma_index(__func__, gma, x);
        return x;
}

#define DEFINE_PPGTT_GMA_TO_INDEX(prefix, ename, exp) \
static unsigned long prefix##_gma_to_##ename##_index(unsigned long gma) \
{ \
        unsigned long x = (exp); \
        trace_gma_index(__func__, gma, x); \
        return x; \
}

DEFINE_PPGTT_GMA_TO_INDEX(gen8, pte, (gma >> 12 & 0x1ff));
DEFINE_PPGTT_GMA_TO_INDEX(gen8, pde, (gma >> 21 & 0x1ff));
DEFINE_PPGTT_GMA_TO_INDEX(gen8, l3_pdp, (gma >> 30 & 0x3));
DEFINE_PPGTT_GMA_TO_INDEX(gen8, l4_pdp, (gma >> 30 & 0x1ff));
DEFINE_PPGTT_GMA_TO_INDEX(gen8, pml4, (gma >> 39 & 0x1ff));

static struct intel_gvt_gtt_pte_ops gen8_gtt_pte_ops = {
        .get_entry = gtt_get_entry64,
        .set_entry = gtt_set_entry64,
        .clear_present = gtt_entry_clear_present,
        .set_present = gtt_entry_set_present,
        .test_present = gen8_gtt_test_present,
        .test_pse = gen8_gtt_test_pse,
        .get_pfn = gen8_gtt_get_pfn,
        .set_pfn = gen8_gtt_set_pfn,
};

static struct intel_gvt_gtt_gma_ops gen8_gtt_gma_ops = {
        .gma_to_ggtt_pte_index = gma_to_ggtt_pte_index,
        .gma_to_pte_index = gen8_gma_to_pte_index,
        .gma_to_pde_index = gen8_gma_to_pde_index,
        .gma_to_l3_pdp_index = gen8_gma_to_l3_pdp_index,
        .gma_to_l4_pdp_index = gen8_gma_to_l4_pdp_index,
        .gma_to_pml4_index = gen8_gma_to_pml4_index,
};

static int gtt_entry_p2m(struct intel_vgpu *vgpu, struct intel_gvt_gtt_entry *p,
                struct intel_gvt_gtt_entry *m)
{
        struct intel_gvt_gtt_pte_ops *ops = vgpu->gvt->gtt.pte_ops;
        unsigned long gfn, mfn;

        *m = *p;

        if (!ops->test_present(p))
                return 0;

        gfn = ops->get_pfn(p);

        mfn = intel_gvt_hypervisor_gfn_to_mfn(vgpu, gfn);
        if (mfn == INTEL_GVT_INVALID_ADDR) {
                gvt_vgpu_err("fail to translate gfn: 0x%lx\n", gfn);
                return -ENXIO;
        }

        ops->set_pfn(m, mfn);
        return 0;
}

/*
 * MM helpers.
 */
int intel_vgpu_mm_get_entry(struct intel_vgpu_mm *mm,
                void *page_table, struct intel_gvt_gtt_entry *e,
                unsigned long index)
{
        struct intel_gvt *gvt = mm->vgpu->gvt;
        struct intel_gvt_gtt_pte_ops *ops = gvt->gtt.pte_ops;
        int ret;

        e->type = mm->page_table_entry_type;

        ret = ops->get_entry(page_table, e, index, false, 0, mm->vgpu);
        if (ret)
                return ret;

        ops->test_pse(e);
        return 0;
}

int intel_vgpu_mm_set_entry(struct intel_vgpu_mm *mm,
                void *page_table, struct intel_gvt_gtt_entry *e,
                unsigned long index)
{
        struct intel_gvt *gvt = mm->vgpu->gvt;
        struct intel_gvt_gtt_pte_ops *ops = gvt->gtt.pte_ops;

        return ops->set_entry(page_table, e, index, false, 0, mm->vgpu);
}

/*
 * PPGTT shadow page table helpers.
 */
static inline int ppgtt_spt_get_entry(
                struct intel_vgpu_ppgtt_spt *spt,
                void *page_table, int type,
                struct intel_gvt_gtt_entry *e, unsigned long index,
                bool guest)
{
        struct intel_gvt *gvt = spt->vgpu->gvt;
        struct intel_gvt_gtt_pte_ops *ops = gvt->gtt.pte_ops;
        int ret;

        e->type = get_entry_type(type);

        if (WARN(!gtt_type_is_entry(e->type), "invalid entry type\n"))
                return -EINVAL;

        ret = ops->get_entry(page_table, e, index, guest,
                        spt->guest_page.track.gfn << I915_GTT_PAGE_SHIFT,
                        spt->vgpu);
        if (ret)
                return ret;

        ops->test_pse(e);
        return 0;
}

static inline int ppgtt_spt_set_entry(
                struct intel_vgpu_ppgtt_spt *spt,
                void *page_table, int type,
                struct intel_gvt_gtt_entry *e, unsigned long index,
                bool guest)
{
        struct intel_gvt *gvt = spt->vgpu->gvt;
        struct intel_gvt_gtt_pte_ops *ops = gvt->gtt.pte_ops;

        if (WARN(!gtt_type_is_entry(e->type), "invalid entry type\n"))
                return -EINVAL;

        return ops->set_entry(page_table, e, index, guest,
                        spt->guest_page.track.gfn << I915_GTT_PAGE_SHIFT,
                        spt->vgpu);
}

#define ppgtt_get_guest_entry(spt, e, index) \
        ppgtt_spt_get_entry(spt, NULL, \
                spt->guest_page_type, e, index, true)

#define ppgtt_set_guest_entry(spt, e, index) \
        ppgtt_spt_set_entry(spt, NULL, \
                spt->guest_page_type, e, index, true)

#define ppgtt_get_shadow_entry(spt, e, index) \
        ppgtt_spt_get_entry(spt, spt->shadow_page.vaddr, \
                spt->shadow_page.type, e, index, false)

#define ppgtt_set_shadow_entry(spt, e, index) \
        ppgtt_spt_set_entry(spt, spt->shadow_page.vaddr, \
                spt->shadow_page.type, e, index, false)

/**
 * intel_vgpu_init_page_track - init a page track data structure
 * @vgpu: a vGPU
 * @t: a page track data structure
 * @gfn: guest memory page frame number
 * @handler: the function will be called when target guest memory page has
 * been modified.
 *
 * This function is called when a user wants to prepare a page track data
 * structure to track a guest memory page.
 *
 * Returns:
 * Zero on success, negative error code if failed.
 */
int intel_vgpu_init_page_track(struct intel_vgpu *vgpu,
                struct intel_vgpu_page_track *t,
                unsigned long gfn,
                int (*handler)(void *, u64, void *, int),
                void *data)
{
        INIT_HLIST_NODE(&t->node);

        t->tracked = false;
        t->gfn = gfn;
        t->handler = handler;
        t->data = data;

        hash_add(vgpu->gtt.tracked_guest_page_hash_table, &t->node, t->gfn);
        return 0;
}

/**
 * intel_vgpu_clean_page_track - release a page track data structure
 * @vgpu: a vGPU
 * @t: a page track data structure
 *
 * This function is called before a user frees a page track data structure.
 */
void intel_vgpu_clean_page_track(struct intel_vgpu *vgpu,
                struct intel_vgpu_page_track *t)
{
        if (!hlist_unhashed(&t->node))
                hash_del(&t->node);

        if (t->tracked)
                intel_gvt_hypervisor_disable_page_track(vgpu, t);
}

/**
 * intel_vgpu_find_tracked_page - find a tracked guest page
 * @vgpu: a vGPU
 * @gfn: guest memory page frame number
 *
 * This function is called when the emulation layer wants to figure out if a
 * trapped GFN is a tracked guest page.
 *
 * Returns:
 * Pointer to page track data structure, NULL if not found.
 */
struct intel_vgpu_page_track *intel_vgpu_find_tracked_page(
                struct intel_vgpu *vgpu, unsigned long gfn)
{
        struct intel_vgpu_page_track *t;

        hash_for_each_possible(vgpu->gtt.tracked_guest_page_hash_table,
                        t, node, gfn) {
                if (t->gfn == gfn)
                        return t;
        }
        return NULL;
}

static int init_guest_page(struct intel_vgpu *vgpu,
                struct intel_vgpu_guest_page *p,
                unsigned long gfn,
                int (*handler)(void *, u64, void *, int),
                void *data)
{
        p->oos_page = NULL;
        p->write_cnt = 0;

        return intel_vgpu_init_page_track(vgpu, &p->track, gfn, handler, data);
}

static int detach_oos_page(struct intel_vgpu *vgpu,
                struct intel_vgpu_oos_page *oos_page);

static void clean_guest_page(struct intel_vgpu *vgpu,
                struct intel_vgpu_guest_page *p)
{
        if (p->oos_page)
                detach_oos_page(vgpu, p->oos_page);

        intel_vgpu_clean_page_track(vgpu, &p->track);
}

static inline int init_shadow_page(struct intel_vgpu *vgpu,
                struct intel_vgpu_shadow_page *p, int type, bool hash)
{
        struct device *kdev = &vgpu->gvt->dev_priv->drm.pdev->dev;
        dma_addr_t daddr;

        daddr = dma_map_page(kdev, p->page, 0, 4096, PCI_DMA_BIDIRECTIONAL);
        if (dma_mapping_error(kdev, daddr)) {
                gvt_vgpu_err("fail to map dma addr\n");
                return -EINVAL;
        }

        p->vaddr = page_address(p->page);
        p->type = type;

        INIT_HLIST_NODE(&p->node);

        p->mfn = daddr >> I915_GTT_PAGE_SHIFT;
        if (hash)
                hash_add(vgpu->gtt.shadow_page_hash_table, &p->node, p->mfn);
        return 0;
}

static inline void clean_shadow_page(struct intel_vgpu *vgpu,
                struct intel_vgpu_shadow_page *p)
{
        struct device *kdev = &vgpu->gvt->dev_priv->drm.pdev->dev;

        dma_unmap_page(kdev, p->mfn << I915_GTT_PAGE_SHIFT, 4096,
                        PCI_DMA_BIDIRECTIONAL);

        if (!hlist_unhashed(&p->node))
                hash_del(&p->node);
}

static inline struct intel_vgpu_shadow_page *find_shadow_page(
                struct intel_vgpu *vgpu, unsigned long mfn)
{
        struct intel_vgpu_shadow_page *p;

        hash_for_each_possible(vgpu->gtt.shadow_page_hash_table,
                p, node, mfn) {
                if (p->mfn == mfn)
                        return p;
        }
        return NULL;
}

#define page_track_to_guest_page(ptr) \
        container_of(ptr, struct intel_vgpu_guest_page, track)

#define guest_page_to_ppgtt_spt(ptr) \
        container_of(ptr, struct intel_vgpu_ppgtt_spt, guest_page)

#define shadow_page_to_ppgtt_spt(ptr) \
        container_of(ptr, struct intel_vgpu_ppgtt_spt, shadow_page)

static void *alloc_spt(gfp_t gfp_mask)
{
        struct intel_vgpu_ppgtt_spt *spt;

        spt = kzalloc(sizeof(*spt), gfp_mask);
        if (!spt)
                return NULL;

        spt->shadow_page.page = alloc_page(gfp_mask);
        if (!spt->shadow_page.page) {
                kfree(spt);
                return NULL;
        }
        return spt;
}

static void free_spt(struct intel_vgpu_ppgtt_spt *spt)
{
        __free_page(spt->shadow_page.page);
        kfree(spt);
}

static void ppgtt_free_shadow_page(struct intel_vgpu_ppgtt_spt *spt)
{
        trace_spt_free(spt->vgpu->id, spt, spt->shadow_page.type);

        clean_shadow_page(spt->vgpu, &spt->shadow_page);
        clean_guest_page(spt->vgpu, &spt->guest_page);
        list_del_init(&spt->post_shadow_list);

        free_spt(spt);
}

static void ppgtt_free_all_shadow_page(struct intel_vgpu *vgpu)
{
        struct hlist_node *n;
        struct intel_vgpu_shadow_page *sp;
        int i;

        hash_for_each_safe(vgpu->gtt.shadow_page_hash_table, i, n, sp, node)
                ppgtt_free_shadow_page(shadow_page_to_ppgtt_spt(sp));
}

static int ppgtt_handle_guest_write_page_table_bytes(
                struct intel_vgpu_guest_page *gpt,
                u64 pa, void *p_data, int bytes);

static int ppgtt_write_protection_handler(void *data, u64 pa,
                void *p_data, int bytes)
{
        struct intel_vgpu_page_track *t = data;
        struct intel_vgpu_guest_page *p = page_track_to_guest_page(t);
        int ret;

        if (bytes != 4 && bytes != 8)
                return -EINVAL;

        if (!t->tracked)
                return -EINVAL;

        ret = ppgtt_handle_guest_write_page_table_bytes(p,
                pa, p_data, bytes);
        if (ret)
                return ret;
        return ret;
}

static int reclaim_one_mm(struct intel_gvt *gvt);

static struct intel_vgpu_ppgtt_spt *ppgtt_alloc_shadow_page(
                struct intel_vgpu *vgpu, int type, unsigned long gfn)
{
        struct intel_vgpu_ppgtt_spt *spt = NULL;
        int ret;

retry:
        spt = alloc_spt(GFP_KERNEL | __GFP_ZERO);
        if (!spt) {
                if (reclaim_one_mm(vgpu->gvt))
                        goto retry;

                gvt_vgpu_err("fail to allocate ppgtt shadow page\n");
                return ERR_PTR(-ENOMEM);
        }

        spt->vgpu = vgpu;
        spt->guest_page_type = type;
        atomic_set(&spt->refcount, 1);
        INIT_LIST_HEAD(&spt->post_shadow_list);

        /*
         * TODO: guest page type may be different with shadow page type,
         *       when we support PSE page in future.
         */
        ret = init_shadow_page(vgpu, &spt->shadow_page, type, true);
        if (ret) {
                gvt_vgpu_err("fail to initialize shadow page for spt\n");
                goto err;
        }

        ret = init_guest_page(vgpu, &spt->guest_page,
                        gfn, ppgtt_write_protection_handler, NULL);
        if (ret) {
                gvt_vgpu_err("fail to initialize guest page for spt\n");
                goto err;
        }

        trace_spt_alloc(vgpu->id, spt, type, spt->shadow_page.mfn, gfn);
        return spt;
err:
        ppgtt_free_shadow_page(spt);
        return ERR_PTR(ret);
}

static struct intel_vgpu_ppgtt_spt *ppgtt_find_shadow_page(
                struct intel_vgpu *vgpu, unsigned long mfn)
{
        struct intel_vgpu_shadow_page *p = find_shadow_page(vgpu, mfn);

        if (p)
                return shadow_page_to_ppgtt_spt(p);

        gvt_vgpu_err("fail to find ppgtt shadow page: 0x%lx\n", mfn);
        return NULL;
}

#define pt_entry_size_shift(spt) \
        ((spt)->vgpu->gvt->device_info.gtt_entry_size_shift)

#define pt_entries(spt) \
        (I915_GTT_PAGE_SIZE >> pt_entry_size_shift(spt))

#define for_each_present_guest_entry(spt, e, i) \
        for (i = 0; i < pt_entries(spt); i++) \
                if (!ppgtt_get_guest_entry(spt, e, i) && \
                    spt->vgpu->gvt->gtt.pte_ops->test_present(e))

#define for_each_present_shadow_entry(spt, e, i) \
        for (i = 0; i < pt_entries(spt); i++) \
                if (!ppgtt_get_shadow_entry(spt, e, i) && \
                    spt->vgpu->gvt->gtt.pte_ops->test_present(e))

static void ppgtt_get_shadow_page(struct intel_vgpu_ppgtt_spt *spt)
{
        int v = atomic_read(&spt->refcount);

        trace_spt_refcount(spt->vgpu->id, "inc", spt, v, (v + 1));

        atomic_inc(&spt->refcount);
}

static int ppgtt_invalidate_shadow_page(struct intel_vgpu_ppgtt_spt *spt);

static int ppgtt_invalidate_shadow_page_by_shadow_entry(struct intel_vgpu *vgpu,
                struct intel_gvt_gtt_entry *e)
{
        struct intel_gvt_gtt_pte_ops *ops = vgpu->gvt->gtt.pte_ops;
        struct intel_vgpu_ppgtt_spt *s;
        intel_gvt_gtt_type_t cur_pt_type;

        if (WARN_ON(!gtt_type_is_pt(get_next_pt_type(e->type))))
                return -EINVAL;

        if (e->type != GTT_TYPE_PPGTT_ROOT_L3_ENTRY
                && e->type != GTT_TYPE_PPGTT_ROOT_L4_ENTRY) {
                cur_pt_type = get_next_pt_type(e->type) + 1;
                if (ops->get_pfn(e) ==
                        vgpu->gtt.scratch_pt[cur_pt_type].page_mfn)
                        return 0;
        }
        s = ppgtt_find_shadow_page(vgpu, ops->get_pfn(e));
        if (!s) {
                gvt_vgpu_err("fail to find shadow page: mfn: 0x%lx\n",
                                ops->get_pfn(e));
                return -ENXIO;
        }
        return ppgtt_invalidate_shadow_page(s);
}

static int ppgtt_invalidate_shadow_page(struct intel_vgpu_ppgtt_spt *spt)
{
        struct intel_vgpu *vgpu = spt->vgpu;
        struct intel_gvt_gtt_entry e;
        unsigned long index;
        int ret;
        int v = atomic_read(&spt->refcount);

        trace_spt_change(spt->vgpu->id, "die", spt,
                        spt->guest_page.track.gfn, spt->shadow_page.type);

        trace_spt_refcount(spt->vgpu->id, "dec", spt, v, (v - 1));

        if (atomic_dec_return(&spt->refcount) > 0)
                return 0;

        if (gtt_type_is_pte_pt(spt->shadow_page.type))
                goto release;

        for_each_present_shadow_entry(spt, &e, index) {
                if (!gtt_type_is_pt(get_next_pt_type(e.type))) {
                        gvt_vgpu_err("GVT doesn't support pse bit for now\n");
                        return -EINVAL;
                }
                ret = ppgtt_invalidate_shadow_page_by_shadow_entry(
                                spt->vgpu, &e);
                if (ret)
                        goto fail;
        }
release:
        trace_spt_change(spt->vgpu->id, "release", spt,
                        spt->guest_page.track.gfn, spt->shadow_page.type);
        ppgtt_free_shadow_page(spt);
        return 0;
fail:
        gvt_vgpu_err("fail: shadow page %p shadow entry 0x%llx type %d\n",
                        spt, e.val64, e.type);
        return ret;
}

static int ppgtt_populate_shadow_page(struct intel_vgpu_ppgtt_spt *spt);

static struct intel_vgpu_ppgtt_spt *ppgtt_populate_shadow_page_by_guest_entry(
                struct intel_vgpu *vgpu, struct intel_gvt_gtt_entry *we)
{
        struct intel_gvt_gtt_pte_ops *ops = vgpu->gvt->gtt.pte_ops;
        struct intel_vgpu_ppgtt_spt *s = NULL;
        struct intel_vgpu_guest_page *g;
        struct intel_vgpu_page_track *t;
        int ret;

        if (WARN_ON(!gtt_type_is_pt(get_next_pt_type(we->type)))) {
                ret = -EINVAL;
                goto fail;
        }

        t = intel_vgpu_find_tracked_page(vgpu, ops->get_pfn(we));
        if (t) {
                g = page_track_to_guest_page(t);
                s = guest_page_to_ppgtt_spt(g);
                ppgtt_get_shadow_page(s);
        } else {
                int type = get_next_pt_type(we->type);

                s = ppgtt_alloc_shadow_page(vgpu, type, ops->get_pfn(we));
                if (IS_ERR(s)) {
                        ret = PTR_ERR(s);
                        goto fail;
                }

                ret = intel_gvt_hypervisor_enable_page_track(vgpu,
                                &s->guest_page.track);
                if (ret)
                        goto fail;

                ret = ppgtt_populate_shadow_page(s);
                if (ret)
                        goto fail;

                trace_spt_change(vgpu->id, "new", s, s->guest_page.track.gfn,
                        s->shadow_page.type);
        }
        return s;
fail:
        gvt_vgpu_err("fail: shadow page %p guest entry 0x%llx type %d\n",
                        s, we->val64, we->type);
        return ERR_PTR(ret);
}

static inline void ppgtt_generate_shadow_entry(struct intel_gvt_gtt_entry *se,
                struct intel_vgpu_ppgtt_spt *s, struct intel_gvt_gtt_entry *ge)
{
        struct intel_gvt_gtt_pte_ops *ops = s->vgpu->gvt->gtt.pte_ops;

        se->type = ge->type;
        se->val64 = ge->val64;

        ops->set_pfn(se, s->shadow_page.mfn);
}

static int ppgtt_populate_shadow_page(struct intel_vgpu_ppgtt_spt *spt)
{
        struct intel_vgpu *vgpu = spt->vgpu;
        struct intel_gvt *gvt = vgpu->gvt;

        struct intel_gvt_gtt_pte_ops *ops = gvt->gtt.pte_ops;
        struct intel_vgpu_ppgtt_spt *s;
        struct intel_gvt_gtt_entry se, ge;
        unsigned long gfn, i;
        int ret;

        trace_spt_change(spt->vgpu->id, "born", spt,
                        spt->guest_page.track.gfn, spt->shadow_page.type);

        if (gtt_type_is_pte_pt(spt->shadow_page.type)) {
                for_each_present_guest_entry(spt, &ge, i) {
                        gfn = ops->get_pfn(&ge);
                        if (!intel_gvt_hypervisor_is_valid_gfn(vgpu, gfn) ||
                                gtt_entry_p2m(vgpu, &ge, &se))
                                ops->set_pfn(&se, gvt->gtt.scratch_mfn);
                        ppgtt_set_shadow_entry(spt, &se, i);
                }
                return 0;
        }

        for_each_present_guest_entry(spt, &ge, i) {
                if (!gtt_type_is_pt(get_next_pt_type(ge.type))) {
                        gvt_vgpu_err("GVT doesn't support pse bit now\n");
                        ret = -EINVAL;
                        goto fail;
                }

                s = ppgtt_populate_shadow_page_by_guest_entry(vgpu, &ge);
                if (IS_ERR(s)) {
                        ret = PTR_ERR(s);
                        goto fail;
                }
                ppgtt_get_shadow_entry(spt, &se, i);
                ppgtt_generate_shadow_entry(&se, s, &ge);
                ppgtt_set_shadow_entry(spt, &se, i);
        }
        return 0;
fail:
        gvt_vgpu_err("fail: shadow page %p guest entry 0x%llx type %d\n",
                        spt, ge.val64, ge.type);
        return ret;
}

static int ppgtt_handle_guest_entry_removal(struct intel_vgpu_guest_page *gpt,
                struct intel_gvt_gtt_entry *se, unsigned long index)
{
        struct intel_vgpu_ppgtt_spt *spt = guest_page_to_ppgtt_spt(gpt);
        struct intel_vgpu_shadow_page *sp = &spt->shadow_page;
        struct intel_vgpu *vgpu = spt->vgpu;
        struct intel_gvt_gtt_pte_ops *ops = vgpu->gvt->gtt.pte_ops;
        int ret;

        trace_gpt_change(spt->vgpu->id, "remove", spt, sp->type, se->val64,
                         index);

        if (!ops->test_present(se))
                return 0;

        if (ops->get_pfn(se) == vgpu->gtt.scratch_pt[sp->type].page_mfn)
                return 0;

        if (gtt_type_is_pt(get_next_pt_type(se->type))) {
                struct intel_vgpu_ppgtt_spt *s =
                        ppgtt_find_shadow_page(vgpu, ops->get_pfn(se));
                if (!s) {
                        gvt_vgpu_err("fail to find guest page\n");
                        ret = -ENXIO;
                        goto fail;
                }
                ret = ppgtt_invalidate_shadow_page(s);
                if (ret)
                        goto fail;
        }
        return 0;
fail:
        gvt_vgpu_err("fail: shadow page %p guest entry 0x%llx type %d\n",
                        spt, se->val64, se->type);
        return ret;
}

static int ppgtt_handle_guest_entry_add(struct intel_vgpu_guest_page *gpt,
                struct intel_gvt_gtt_entry *we, unsigned long index)
{
        struct intel_vgpu_ppgtt_spt *spt = guest_page_to_ppgtt_spt(gpt);
        struct intel_vgpu_shadow_page *sp = &spt->shadow_page;
        struct intel_vgpu *vgpu = spt->vgpu;
        struct intel_gvt_gtt_entry m;
        struct intel_vgpu_ppgtt_spt *s;
        int ret;

        trace_gpt_change(spt->vgpu->id, "add", spt, sp->type,
                we->val64, index);

        if (gtt_type_is_pt(get_next_pt_type(we->type))) {
                s = ppgtt_populate_shadow_page_by_guest_entry(vgpu, we);
                if (IS_ERR(s)) {
                        ret = PTR_ERR(s);
                        goto fail;
                }
                ppgtt_get_shadow_entry(spt, &m, index);
                ppgtt_generate_shadow_entry(&m, s, we);
                ppgtt_set_shadow_entry(spt, &m, index);
        } else {
                ret = gtt_entry_p2m(vgpu, we, &m);
                if (ret)
                        goto fail;
                ppgtt_set_shadow_entry(spt, &m, index);
        }
        return 0;
fail:
        gvt_vgpu_err("fail: spt %p guest entry 0x%llx type %d\n",
                spt, we->val64, we->type);
        return ret;
}

static int sync_oos_page(struct intel_vgpu *vgpu,
                struct intel_vgpu_oos_page *oos_page)
{
        const struct intel_gvt_device_info *info = &vgpu->gvt->device_info;
        struct intel_gvt *gvt = vgpu->gvt;
        struct intel_gvt_gtt_pte_ops *ops = gvt->gtt.pte_ops;
        struct intel_vgpu_ppgtt_spt *spt =
                guest_page_to_ppgtt_spt(oos_page->guest_page);
        struct intel_gvt_gtt_entry old, new, m;
        int index;
        int ret;

        trace_oos_change(vgpu->id, "sync", oos_page->id,
                        oos_page->guest_page, spt->guest_page_type);

        old.type = new.type = get_entry_type(spt->guest_page_type);
        old.val64 = new.val64 = 0;

        for (index = 0; index < (I915_GTT_PAGE_SIZE >>
                                info->gtt_entry_size_shift); index++) {
                ops->get_entry(oos_page->mem, &old, index, false, 0, vgpu);
                ops->get_entry(NULL, &new, index, true,
                        oos_page->guest_page->track.gfn << PAGE_SHIFT, vgpu);

                if (old.val64 == new.val64
                        && !test_and_clear_bit(index, spt->post_shadow_bitmap))
                        continue;

                trace_oos_sync(vgpu->id, oos_page->id,
                                oos_page->guest_page, spt->guest_page_type,
                                new.val64, index);

                ret = gtt_entry_p2m(vgpu, &new, &m);
                if (ret)
                        return ret;

                ops->set_entry(oos_page->mem, &new, index, false, 0, vgpu);
                ppgtt_set_shadow_entry(spt, &m, index);
        }

        oos_page->guest_page->write_cnt = 0;
        list_del_init(&spt->post_shadow_list);
        return 0;
}

static int detach_oos_page(struct intel_vgpu *vgpu,
                struct intel_vgpu_oos_page *oos_page)
{
        struct intel_gvt *gvt = vgpu->gvt;
        struct intel_vgpu_ppgtt_spt *spt =
                guest_page_to_ppgtt_spt(oos_page->guest_page);

        trace_oos_change(vgpu->id, "detach", oos_page->id,
                        oos_page->guest_page, spt->guest_page_type);

        oos_page->guest_page->write_cnt = 0;
        oos_page->guest_page->oos_page = NULL;
        oos_page->guest_page = NULL;

        list_del_init(&oos_page->vm_list);
        list_move_tail(&oos_page->list, &gvt->gtt.oos_page_free_list_head);

        return 0;
}

static int attach_oos_page(struct intel_vgpu *vgpu,
                struct intel_vgpu_oos_page *oos_page,
                struct intel_vgpu_guest_page *gpt)
{
        struct intel_gvt *gvt = vgpu->gvt;
        int ret;

        ret = intel_gvt_hypervisor_read_gpa(vgpu,
                        gpt->track.gfn << I915_GTT_PAGE_SHIFT,
                        oos_page->mem, I915_GTT_PAGE_SIZE);
        if (ret)
                return ret;

        oos_page->guest_page = gpt;
        gpt->oos_page = oos_page;

        list_move_tail(&oos_page->list, &gvt->gtt.oos_page_use_list_head);

        trace_oos_change(vgpu->id, "attach", gpt->oos_page->id,
                        gpt, guest_page_to_ppgtt_spt(gpt)->guest_page_type);
        return 0;
}

static int ppgtt_set_guest_page_sync(struct intel_vgpu *vgpu,
                struct intel_vgpu_guest_page *gpt)
{
        int ret;

        ret = intel_gvt_hypervisor_enable_page_track(vgpu, &gpt->track);
        if (ret)
                return ret;

        trace_oos_change(vgpu->id, "set page sync", gpt->oos_page->id,
                        gpt, guest_page_to_ppgtt_spt(gpt)->guest_page_type);

        list_del_init(&gpt->oos_page->vm_list);
        return sync_oos_page(vgpu, gpt->oos_page);
}

static int ppgtt_allocate_oos_page(struct intel_vgpu *vgpu,
                struct intel_vgpu_guest_page *gpt)
{
        struct intel_gvt *gvt = vgpu->gvt;
        struct intel_gvt_gtt *gtt = &gvt->gtt;
        struct intel_vgpu_oos_page *oos_page = gpt->oos_page;
        int ret;

        WARN(oos_page, "shadow PPGTT page has already has a oos page\n");

        if (list_empty(&gtt->oos_page_free_list_head)) {
                oos_page = container_of(gtt->oos_page_use_list_head.next,
                        struct intel_vgpu_oos_page, list);
                ret = ppgtt_set_guest_page_sync(vgpu, oos_page->guest_page);
                if (ret)
                        return ret;
                ret = detach_oos_page(vgpu, oos_page);
                if (ret)
                        return ret;
        } else
                oos_page = container_of(gtt->oos_page_free_list_head.next,
                        struct intel_vgpu_oos_page, list);
        return attach_oos_page(vgpu, oos_page, gpt);
}

static int ppgtt_set_guest_page_oos(struct intel_vgpu *vgpu,
                struct intel_vgpu_guest_page *gpt)
{
        struct intel_vgpu_oos_page *oos_page = gpt->oos_page;

        if (WARN(!oos_page, "shadow PPGTT page should have a oos page\n"))
                return -EINVAL;

        trace_oos_change(vgpu->id, "set page out of sync", gpt->oos_page->id,
                        gpt, guest_page_to_ppgtt_spt(gpt)->guest_page_type);

        list_add_tail(&oos_page->vm_list, &vgpu->gtt.oos_page_list_head);
        return intel_gvt_hypervisor_disable_page_track(vgpu, &gpt->track);
}

/**
 * intel_vgpu_sync_oos_pages - sync all the out-of-synced shadow for vGPU
 * @vgpu: a vGPU
 *
 * This function is called before submitting a guest workload to host,
 * to sync all the out-of-synced shadow for vGPU
 *
 * Returns:
 * Zero on success, negative error code if failed.
 */
int intel_vgpu_sync_oos_pages(struct intel_vgpu *vgpu)
{
        struct list_head *pos, *n;
        struct intel_vgpu_oos_page *oos_page;
        int ret;

        if (!enable_out_of_sync)
                return 0;

        list_for_each_safe(pos, n, &vgpu->gtt.oos_page_list_head) {
                oos_page = container_of(pos,
                                struct intel_vgpu_oos_page, vm_list);
                ret = ppgtt_set_guest_page_sync(vgpu, oos_page->guest_page);
                if (ret)
                        return ret;
        }
        return 0;
}

/*
 * The heart of PPGTT shadow page table.
 */
static int ppgtt_handle_guest_write_page_table(
                struct intel_vgpu_guest_page *gpt,
                struct intel_gvt_gtt_entry *we, unsigned long index)
{
        struct intel_vgpu_ppgtt_spt *spt = guest_page_to_ppgtt_spt(gpt);
        struct intel_vgpu *vgpu = spt->vgpu;
        int type = spt->shadow_page.type;
        struct intel_gvt_gtt_pte_ops *ops = vgpu->gvt->gtt.pte_ops;
        struct intel_gvt_gtt_entry se;

        int ret;
        int new_present;

        new_present = ops->test_present(we);

        /*
         * Adding the new entry first and then removing the old one, that can
         * guarantee the ppgtt table is validated during the window between
         * adding and removal.
         */
        ppgtt_get_shadow_entry(spt, &se, index);

        if (new_present) {
                ret = ppgtt_handle_guest_entry_add(gpt, we, index);
                if (ret)
                        goto fail;
        }

        ret = ppgtt_handle_guest_entry_removal(gpt, &se, index);
        if (ret)
                goto fail;

        if (!new_present) {
                ops->set_pfn(&se, vgpu->gtt.scratch_pt[type].page_mfn);
                ppgtt_set_shadow_entry(spt, &se, index);
        }

        return 0;
fail:
        gvt_vgpu_err("fail: shadow page %p guest entry 0x%llx type %d.\n",
                        spt, we->val64, we->type);
        return ret;
}

static inline bool can_do_out_of_sync(struct intel_vgpu_guest_page *gpt)
{
        return enable_out_of_sync
                && gtt_type_is_pte_pt(
                        guest_page_to_ppgtt_spt(gpt)->guest_page_type)
                && gpt->write_cnt >= 2;
}

static void ppgtt_set_post_shadow(struct intel_vgpu_ppgtt_spt *spt,
                unsigned long index)
{
        set_bit(index, spt->post_shadow_bitmap);
        if (!list_empty(&spt->post_shadow_list))
                return;

        list_add_tail(&spt->post_shadow_list,
                        &spt->vgpu->gtt.post_shadow_list_head);
}

/**
 * intel_vgpu_flush_post_shadow - flush the post shadow transactions
 * @vgpu: a vGPU
 *
 * This function is called before submitting a guest workload to host,
 * to flush all the post shadows for a vGPU.
 *
 * Returns:
 * Zero on success, negative error code if failed.
 */
int intel_vgpu_flush_post_shadow(struct intel_vgpu *vgpu)
{
        struct list_head *pos, *n;
        struct intel_vgpu_ppgtt_spt *spt;
        struct intel_gvt_gtt_entry ge;
        unsigned long index;
        int ret;

        list_for_each_safe(pos, n, &vgpu->gtt.post_shadow_list_head) {
                spt = container_of(pos, struct intel_vgpu_ppgtt_spt,
                                post_shadow_list);

                for_each_set_bit(index, spt->post_shadow_bitmap,
                                GTT_ENTRY_NUM_IN_ONE_PAGE) {
                        ppgtt_get_guest_entry(spt, &ge, index);

                        ret = ppgtt_handle_guest_write_page_table(
                                        &spt->guest_page, &ge, index);
                        if (ret)
                                return ret;
                        clear_bit(index, spt->post_shadow_bitmap);
                }
                list_del_init(&spt->post_shadow_list);
        }
        return 0;
}

static int ppgtt_handle_guest_write_page_table_bytes(
                struct intel_vgpu_guest_page *gpt,
                u64 pa, void *p_data, int bytes)
{
        struct intel_vgpu_ppgtt_spt *spt = guest_page_to_ppgtt_spt(gpt);
        struct intel_vgpu *vgpu = spt->vgpu;
        struct intel_gvt_gtt_pte_ops *ops = vgpu->gvt->gtt.pte_ops;
        const struct intel_gvt_device_info *info = &vgpu->gvt->device_info;
        struct intel_gvt_gtt_entry we, se;
        unsigned long index;
        int ret;

        index = (pa & (PAGE_SIZE - 1)) >> info->gtt_entry_size_shift;

        ppgtt_get_guest_entry(spt, &we, index);

        ops->test_pse(&we);

        if (bytes == info->gtt_entry_size) {
                ret = ppgtt_handle_guest_write_page_table(gpt, &we, index);
                if (ret)
                        return ret;
        } else {
                if (!test_bit(index, spt->post_shadow_bitmap)) {
                        int type = spt->shadow_page.type;

                        ppgtt_get_shadow_entry(spt, &se, index);
                        ret = ppgtt_handle_guest_entry_removal(gpt, &se, index);
                        if (ret)
                                return ret;
                        ops->set_pfn(&se, vgpu->gtt.scratch_pt[type].page_mfn);
                        ppgtt_set_shadow_entry(spt, &se, index);
                }
                ppgtt_set_post_shadow(spt, index);
        }

        if (!enable_out_of_sync)
                return 0;

        gpt->write_cnt++;

        if (gpt->oos_page)
                ops->set_entry(gpt->oos_page->mem, &we, index,
                                false, 0, vgpu);

        if (can_do_out_of_sync(gpt)) {
                if (!gpt->oos_page)
                        ppgtt_allocate_oos_page(vgpu, gpt);

                ret = ppgtt_set_guest_page_oos(vgpu, gpt);
                if (ret < 0)
                        return ret;
        }
        return 0;
}

/*
 * mm page table allocation policy for bdw+
 *  - for ggtt, only virtual page table will be allocated.
 *  - for ppgtt, dedicated virtual/shadow page table will be allocated.
 */
static int gen8_mm_alloc_page_table(struct intel_vgpu_mm *mm)
{
        struct intel_vgpu *vgpu = mm->vgpu;
        struct intel_gvt *gvt = vgpu->gvt;
        const struct intel_gvt_device_info *info = &gvt->device_info;
        void *mem;

        if (mm->type == INTEL_GVT_MM_PPGTT) {
                mm->page_table_entry_cnt = 4;
                mm->page_table_entry_size = mm->page_table_entry_cnt *
                        info->gtt_entry_size;
                mem = kzalloc(mm->has_shadow_page_table ?
                        mm->page_table_entry_size * 2
                                : mm->page_table_entry_size, GFP_KERNEL);
                if (!mem)
                        return -ENOMEM;
                mm->virtual_page_table = mem;
                if (!mm->has_shadow_page_table)
                        return 0;
                mm->shadow_page_table = mem + mm->page_table_entry_size;
        } else if (mm->type == INTEL_GVT_MM_GGTT) {
                mm->page_table_entry_cnt =
                        (gvt_ggtt_gm_sz(gvt) >> I915_GTT_PAGE_SHIFT);
                mm->page_table_entry_size = mm->page_table_entry_cnt *
                        info->gtt_entry_size;
                mem = vzalloc(mm->page_table_entry_size);
                if (!mem)
                        return -ENOMEM;
                mm->virtual_page_table = mem;
        }
        return 0;
}

static void gen8_mm_free_page_table(struct intel_vgpu_mm *mm)
{
        if (mm->type == INTEL_GVT_MM_PPGTT) {
                kfree(mm->virtual_page_table);
        } else if (mm->type == INTEL_GVT_MM_GGTT) {
                if (mm->virtual_page_table)
                        vfree(mm->virtual_page_table);
        }
        mm->virtual_page_table = mm->shadow_page_table = NULL;
}

static void invalidate_mm(struct intel_vgpu_mm *mm)
{
        struct intel_vgpu *vgpu = mm->vgpu;
        struct intel_gvt *gvt = vgpu->gvt;
        struct intel_gvt_gtt *gtt = &gvt->gtt;
        struct intel_gvt_gtt_pte_ops *ops = gtt->pte_ops;
        struct intel_gvt_gtt_entry se;
        int i;

        if (WARN_ON(!mm->has_shadow_page_table || !mm->shadowed))
                return;

        for (i = 0; i < mm->page_table_entry_cnt; i++) {
                ppgtt_get_shadow_root_entry(mm, &se, i);
                if (!ops->test_present(&se))
                        continue;
                ppgtt_invalidate_shadow_page_by_shadow_entry(
                                vgpu, &se);
                se.val64 = 0;
                ppgtt_set_shadow_root_entry(mm, &se, i);

                trace_gpt_change(vgpu->id, "destroy root pointer",
                                NULL, se.type, se.val64, i);
        }
        mm->shadowed = false;
}

/**
 * intel_vgpu_destroy_mm - destroy a mm object
 * @mm: a kref object
 *
 * This function is used to destroy a mm object for vGPU
 *
 */
void intel_vgpu_destroy_mm(struct kref *mm_ref)
{
        struct intel_vgpu_mm *mm = container_of(mm_ref, typeof(*mm), ref);
        struct intel_vgpu *vgpu = mm->vgpu;
        struct intel_gvt *gvt = vgpu->gvt;
        struct intel_gvt_gtt *gtt = &gvt->gtt;

        if (!mm->initialized)
                goto out;

        list_del(&mm->list);
        list_del(&mm->lru_list);

        if (mm->has_shadow_page_table)
                invalidate_mm(mm);

        gtt->mm_free_page_table(mm);
out:
        kfree(mm);
}

static int shadow_mm(struct intel_vgpu_mm *mm)
{
        struct intel_vgpu *vgpu = mm->vgpu;
        struct intel_gvt *gvt = vgpu->gvt;
        struct intel_gvt_gtt *gtt = &gvt->gtt;
        struct intel_gvt_gtt_pte_ops *ops = gtt->pte_ops;
        struct intel_vgpu_ppgtt_spt *spt;
        struct intel_gvt_gtt_entry ge, se;
        int i;
        int ret;

        if (WARN_ON(!mm->has_shadow_page_table || mm->shadowed))
                return 0;

        mm->shadowed = true;

        for (i = 0; i < mm->page_table_entry_cnt; i++) {
                ppgtt_get_guest_root_entry(mm, &ge, i);
                if (!ops->test_present(&ge))
                        continue;

                trace_gpt_change(vgpu->id, __func__, NULL,
                                ge.type, ge.val64, i);

                spt = ppgtt_populate_shadow_page_by_guest_entry(vgpu, &ge);
                if (IS_ERR(spt)) {
                        gvt_vgpu_err("fail to populate guest root pointer\n");
                        ret = PTR_ERR(spt);
                        goto fail;
                }
                ppgtt_generate_shadow_entry(&se, spt, &ge);
                ppgtt_set_shadow_root_entry(mm, &se, i);

                trace_gpt_change(vgpu->id, "populate root pointer",
                                NULL, se.type, se.val64, i);
        }
        return 0;
fail:
        invalidate_mm(mm);
        return ret;
}

/**
 * intel_vgpu_create_mm - create a mm object for a vGPU
 * @vgpu: a vGPU
 * @mm_type: mm object type, should be PPGTT or GGTT
 * @virtual_page_table: page table root pointers. Could be NULL if user wants
 *      to populate shadow later.
 * @page_table_level: describe the page table level of the mm object
 * @pde_base_index: pde root pointer base in GGTT MMIO.
 *
 * This function is used to create a mm object for a vGPU.
 *
 * Returns:
 * Zero on success, negative error code in pointer if failed.
 */
struct intel_vgpu_mm *intel_vgpu_create_mm(struct intel_vgpu *vgpu,
                int mm_type, void *virtual_page_table, int page_table_level,
                u32 pde_base_index)
{
        struct intel_gvt *gvt = vgpu->gvt;
        struct intel_gvt_gtt *gtt = &gvt->gtt;
        struct intel_vgpu_mm *mm;
        int ret;

        mm = kzalloc(sizeof(*mm), GFP_KERNEL);
        if (!mm) {
                ret = -ENOMEM;
                goto fail;
        }

        mm->type = mm_type;

        if (page_table_level == 1)
                mm->page_table_entry_type = GTT_TYPE_GGTT_PTE;
        else if (page_table_level == 3)
                mm->page_table_entry_type = GTT_TYPE_PPGTT_ROOT_L3_ENTRY;
        else if (page_table_level == 4)
                mm->page_table_entry_type = GTT_TYPE_PPGTT_ROOT_L4_ENTRY;
        else {
                WARN_ON(1);
                ret = -EINVAL;
                goto fail;
        }

        mm->page_table_level = page_table_level;
        mm->pde_base_index = pde_base_index;

        mm->vgpu = vgpu;
        mm->has_shadow_page_table = !!(mm_type == INTEL_GVT_MM_PPGTT);

        kref_init(&mm->ref);
        atomic_set(&mm->pincount, 0);
        INIT_LIST_HEAD(&mm->list);
        INIT_LIST_HEAD(&mm->lru_list);
        list_add_tail(&mm->list, &vgpu->gtt.mm_list_head);

        ret = gtt->mm_alloc_page_table(mm);
        if (ret) {
                gvt_vgpu_err("fail to allocate page table for mm\n");
                goto fail;
        }

        mm->initialized = true;

        if (virtual_page_table)
                memcpy(mm->virtual_page_table, virtual_page_table,
                                mm->page_table_entry_size);

        if (mm->has_shadow_page_table) {
                ret = shadow_mm(mm);
                if (ret)
                        goto fail;
                list_add_tail(&mm->lru_list, &gvt->gtt.mm_lru_list_head);
        }
        return mm;
fail:
        gvt_vgpu_err("fail to create mm\n");
        if (mm)
                intel_gvt_mm_unreference(mm);
        return ERR_PTR(ret);
}

/**
 * intel_vgpu_unpin_mm - decrease the pin count of a vGPU mm object
 * @mm: a vGPU mm object
 *
 * This function is called when user doesn't want to use a vGPU mm object
 */
void intel_vgpu_unpin_mm(struct intel_vgpu_mm *mm)
{
        if (WARN_ON(mm->type != INTEL_GVT_MM_PPGTT))
                return;

        atomic_dec(&mm->pincount);
}

/**
 * intel_vgpu_pin_mm - increase the pin count of a vGPU mm object
 * @vgpu: a vGPU
 *
 * This function is called when user wants to use a vGPU mm object. If this
 * mm object hasn't been shadowed yet, the shadow will be populated at this
 * time.
 *
 * Returns:
 * Zero on success, negative error code if failed.
 */
int intel_vgpu_pin_mm(struct intel_vgpu_mm *mm)
{
        int ret;

        if (WARN_ON(mm->type != INTEL_GVT_MM_PPGTT))
                return 0;

        if (!mm->shadowed) {
                ret = shadow_mm(mm);
                if (ret)
                        return ret;
        }

        atomic_inc(&mm->pincount);
        list_del_init(&mm->lru_list);
        list_add_tail(&mm->lru_list, &mm->vgpu->gvt->gtt.mm_lru_list_head);
        return 0;
}

static int reclaim_one_mm(struct intel_gvt *gvt)
{
        struct intel_vgpu_mm *mm;
        struct list_head *pos, *n;

        list_for_each_safe(pos, n, &gvt->gtt.mm_lru_list_head) {
                mm = container_of(pos, struct intel_vgpu_mm, lru_list);

                if (mm->type != INTEL_GVT_MM_PPGTT)
                        continue;
                if (atomic_read(&mm->pincount))
                        continue;

                list_del_init(&mm->lru_list);
                invalidate_mm(mm);
                return 1;
        }
        return 0;
}

/*
 * GMA translation APIs.
 */
static inline int ppgtt_get_next_level_entry(struct intel_vgpu_mm *mm,
                struct intel_gvt_gtt_entry *e, unsigned long index, bool guest)
{
        struct intel_vgpu *vgpu = mm->vgpu;
        struct intel_gvt_gtt_pte_ops *ops = vgpu->gvt->gtt.pte_ops;
        struct intel_vgpu_ppgtt_spt *s;

        if (WARN_ON(!mm->has_shadow_page_table))
                return -EINVAL;

        s = ppgtt_find_shadow_page(vgpu, ops->get_pfn(e));
        if (!s)
                return -ENXIO;

        if (!guest)
                ppgtt_get_shadow_entry(s, e, index);
        else
                ppgtt_get_guest_entry(s, e, index);
        return 0;
}

/**
 * intel_vgpu_gma_to_gpa - translate a gma to GPA
 * @mm: mm object. could be a PPGTT or GGTT mm object
 * @gma: graphics memory address in this mm object
 *
 * This function is used to translate a graphics memory address in specific
 * graphics memory space to guest physical address.
 *
 * Returns:
 * Guest physical address on success, INTEL_GVT_INVALID_ADDR if failed.
 */
unsigned long intel_vgpu_gma_to_gpa(struct intel_vgpu_mm *mm, unsigned long gma)
{
        struct intel_vgpu *vgpu = mm->vgpu;
        struct intel_gvt *gvt = vgpu->gvt;
        struct intel_gvt_gtt_pte_ops *pte_ops = gvt->gtt.pte_ops;
        struct intel_gvt_gtt_gma_ops *gma_ops = gvt->gtt.gma_ops;
        unsigned long gpa = INTEL_GVT_INVALID_ADDR;
        unsigned long gma_index[4];
        struct intel_gvt_gtt_entry e;
        int i, index;
        int ret;

        if (mm->type != INTEL_GVT_MM_GGTT && mm->type != INTEL_GVT_MM_PPGTT)
                return INTEL_GVT_INVALID_ADDR;

        if (mm->type == INTEL_GVT_MM_GGTT) {
                if (!vgpu_gmadr_is_valid(vgpu, gma))
                        goto err;

                ret = ggtt_get_guest_entry(mm, &e,
                                gma_ops->gma_to_ggtt_pte_index(gma));
                if (ret)
                        goto err;
                gpa = (pte_ops->get_pfn(&e) << I915_GTT_PAGE_SHIFT)
                        + (gma & ~I915_GTT_PAGE_MASK);

                trace_gma_translate(vgpu->id, "ggtt", 0, 0, gma, gpa);
                return gpa;
        }

        switch (mm->page_table_level) {
        case 4:
                ret = ppgtt_get_shadow_root_entry(mm, &e, 0);
                if (ret)
                        goto err;
                gma_index[0] = gma_ops->gma_to_pml4_index(gma);
                gma_index[1] = gma_ops->gma_to_l4_pdp_index(gma);
                gma_index[2] = gma_ops->gma_to_pde_index(gma);
                gma_index[3] = gma_ops->gma_to_pte_index(gma);
                index = 4;
                break;
        case 3:
                ret = ppgtt_get_shadow_root_entry(mm, &e,
                                gma_ops->gma_to_l3_pdp_index(gma));
                if (ret)
                        goto err;
                gma_index[0] = gma_ops->gma_to_pde_index(gma);
                gma_index[1] = gma_ops->gma_to_pte_index(gma);
                index = 2;
                break;
        case 2:
                ret = ppgtt_get_shadow_root_entry(mm, &e,
                                gma_ops->gma_to_pde_index(gma));
                if (ret)
                        goto err;
                gma_index[0] = gma_ops->gma_to_pte_index(gma);
                index = 1;
                break;
        default:
                WARN_ON(1);
                goto err;
        }

        /* walk into the shadow page table and get gpa from guest entry */
        for (i = 0; i < index; i++) {
                ret = ppgtt_get_next_level_entry(mm, &e, gma_index[i],
                        (i == index - 1));
                if (ret)
                        goto err;

                if (!pte_ops->test_present(&e)) {
                        gvt_dbg_core("GMA 0x%lx is not present\n", gma);
                        goto err;
                }
        }

        gpa = (pte_ops->get_pfn(&e) << I915_GTT_PAGE_SHIFT)
                + (gma & ~I915_GTT_PAGE_MASK);

        trace_gma_translate(vgpu->id, "ppgtt", 0,
                        mm->page_table_level, gma, gpa);
        return gpa;
err:
        gvt_vgpu_err("invalid mm type: %d gma %lx\n", mm->type, gma);
        return INTEL_GVT_INVALID_ADDR;
}

static int emulate_gtt_mmio_read(struct intel_vgpu *vgpu,
        unsigned int off, void *p_data, unsigned int bytes)
{
        struct intel_vgpu_mm *ggtt_mm = vgpu->gtt.ggtt_mm;
        const struct intel_gvt_device_info *info = &vgpu->gvt->device_info;
        unsigned long index = off >> info->gtt_entry_size_shift;
        struct intel_gvt_gtt_entry e;

        if (bytes != 4 && bytes != 8)
                return -EINVAL;

        ggtt_get_guest_entry(ggtt_mm, &e, index);
        memcpy(p_data, (void *)&e.val64 + (off & (info->gtt_entry_size - 1)),
                        bytes);
        return 0;
}

/**
 * intel_vgpu_emulate_gtt_mmio_read - emulate GTT MMIO register read
 * @vgpu: a vGPU
 * @off: register offset
 * @p_data: data will be returned to guest
 * @bytes: data length
 *
 * This function is used to emulate the GTT MMIO register read
 *
 * Returns:
 * Zero on success, error code if failed.
 */
int intel_vgpu_emulate_gtt_mmio_read(struct intel_vgpu *vgpu, unsigned int off,
        void *p_data, unsigned int bytes)
{
        const struct intel_gvt_device_info *info = &vgpu->gvt->device_info;
        int ret;

        if (bytes != 4 && bytes != 8)
                return -EINVAL;

        off -= info->gtt_start_offset;
        ret = emulate_gtt_mmio_read(vgpu, off, p_data, bytes);
        return ret;
}

static int emulate_gtt_mmio_write(struct intel_vgpu *vgpu, unsigned int off,
        void *p_data, unsigned int bytes)
{
        struct intel_gvt *gvt = vgpu->gvt;
        const struct intel_gvt_device_info *info = &gvt->device_info;
        struct intel_vgpu_mm *ggtt_mm = vgpu->gtt.ggtt_mm;
        struct intel_gvt_gtt_pte_ops *ops = gvt->gtt.pte_ops;
        unsigned long g_gtt_index = off >> info->gtt_entry_size_shift;
        unsigned long gma, gfn;
        struct intel_gvt_gtt_entry e, m;
        int ret;

        if (bytes != 4 && bytes != 8)
                return -EINVAL;

        gma = g_gtt_index << I915_GTT_PAGE_SHIFT;

        /* the VM may configure the whole GM space when ballooning is used */
        if (!vgpu_gmadr_is_valid(vgpu, gma))
                return 0;

        ggtt_get_guest_entry(ggtt_mm, &e, g_gtt_index);

        memcpy((void *)&e.val64 + (off & (info->gtt_entry_size - 1)), p_data,
                        bytes);

        if (ops->test_present(&e)) {
                gfn = ops->get_pfn(&e);

                /* one PTE update may be issued in multiple writes and the
                 * first write may not construct a valid gfn
                 */
                if (!intel_gvt_hypervisor_is_valid_gfn(vgpu, gfn)) {
                        ops->set_pfn(&m, gvt->gtt.scratch_mfn);
                        goto out;
                }

                ret = gtt_entry_p2m(vgpu, &e, &m);
                if (ret) {
                        gvt_vgpu_err("fail to translate guest gtt entry\n");
                        /* guest driver may read/write the entry when partial
                         * update the entry in this situation p2m will fail
                         * settting the shadow entry to point to a scratch page
                         */
                        ops->set_pfn(&m, gvt->gtt.scratch_mfn);
                }
        } else {
                m = e;
                ops->set_pfn(&m, gvt->gtt.scratch_mfn);
        }

out:
        ggtt_set_shadow_entry(ggtt_mm, &m, g_gtt_index);
        gtt_invalidate(gvt->dev_priv);
        ggtt_set_guest_entry(ggtt_mm, &e, g_gtt_index);
        return 0;
}

/*
 * intel_vgpu_emulate_gtt_mmio_write - emulate GTT MMIO register write
 * @vgpu: a vGPU
 * @off: register offset
 * @p_data: data from guest write
 * @bytes: data length
 *
 * This function is used to emulate the GTT MMIO register write
 *
 * Returns:
 * Zero on success, error code if failed.
 */
int intel_vgpu_emulate_gtt_mmio_write(struct intel_vgpu *vgpu, unsigned int off,
        void *p_data, unsigned int bytes)
{
        const struct intel_gvt_device_info *info = &vgpu->gvt->device_info;
        int ret;

        if (bytes != 4 && bytes != 8)
                return -EINVAL;

        off -= info->gtt_start_offset;
        ret = emulate_gtt_mmio_write(vgpu, off, p_data, bytes);
        return ret;
}

int intel_vgpu_write_protect_handler(struct intel_vgpu *vgpu, u64 pa,
                                     void *p_data, unsigned int bytes)
{
        struct intel_gvt *gvt = vgpu->gvt;
        int ret = 0;

        if (atomic_read(&vgpu->gtt.n_tracked_guest_page)) {
                struct intel_vgpu_page_track *t;

                mutex_lock(&gvt->lock);

                t = intel_vgpu_find_tracked_page(vgpu, pa >> PAGE_SHIFT);
                if (t) {

                        if (unlikely(vgpu->failsafe)) {
                                /* remove write protection to prevent furture traps */
                                intel_vgpu_clean_page_track(vgpu, t);
                        } else {
                                ret = t->handler(t, pa, p_data, bytes);
                                if (ret) {
                                        gvt_err("guest page write error %d, "
                                                "gfn 0x%lx, pa 0x%llx, "
                                                "var 0x%x, len %d\n",
                                                ret, t->gfn, pa,
                                                *(u32 *)p_data, bytes);
                                }
                        }
                }
                mutex_unlock(&gvt->lock);
        }
        return ret;
}


static int alloc_scratch_pages(struct intel_vgpu *vgpu,
                intel_gvt_gtt_type_t type)
{
        struct intel_vgpu_gtt *gtt = &vgpu->gtt;
        struct intel_gvt_gtt_pte_ops *ops = vgpu->gvt->gtt.pte_ops;
        int page_entry_num = I915_GTT_PAGE_SIZE >>
                                vgpu->gvt->device_info.gtt_entry_size_shift;
        void *scratch_pt;
        int i;
        struct device *dev = &vgpu->gvt->dev_priv->drm.pdev->dev;
        dma_addr_t daddr;

        if (WARN_ON(type < GTT_TYPE_PPGTT_PTE_PT || type >= GTT_TYPE_MAX))
                return -EINVAL;

        scratch_pt = (void *)get_zeroed_page(GFP_KERNEL);
        if (!scratch_pt) {
                gvt_vgpu_err("fail to allocate scratch page\n");
                return -ENOMEM;
        }

        daddr = dma_map_page(dev, virt_to_page(scratch_pt), 0,
                        4096, PCI_DMA_BIDIRECTIONAL);
        if (dma_mapping_error(dev, daddr)) {
                gvt_vgpu_err("fail to dmamap scratch_pt\n");
                __free_page(virt_to_page(scratch_pt));
                return -ENOMEM;
        }
        gtt->scratch_pt[type].page_mfn =
                (unsigned long)(daddr >> I915_GTT_PAGE_SHIFT);
        gtt->scratch_pt[type].page = virt_to_page(scratch_pt);
        gvt_dbg_mm("vgpu%d create scratch_pt: type %d mfn=0x%lx\n",
                        vgpu->id, type, gtt->scratch_pt[type].page_mfn);

        /* Build the tree by full filled the scratch pt with the entries which
         * point to the next level scratch pt or scratch page. The
         * scratch_pt[type] indicate the scratch pt/scratch page used by the
         * 'type' pt.
         * e.g. scratch_pt[GTT_TYPE_PPGTT_PDE_PT] is used by
         * GTT_TYPE_PPGTT_PDE_PT level pt, that means this scratch_pt it self
         * is GTT_TYPE_PPGTT_PTE_PT, and full filled by scratch page mfn.
         */
        if (type > GTT_TYPE_PPGTT_PTE_PT && type < GTT_TYPE_MAX) {
                struct intel_gvt_gtt_entry se;

                memset(&se, 0, sizeof(struct intel_gvt_gtt_entry));
                se.type = get_entry_type(type - 1);
                ops->set_pfn(&se, gtt->scratch_pt[type - 1].page_mfn);

                /* The entry parameters like present/writeable/cache type
                 * set to the same as i915's scratch page tree.
                 */
                se.val64 |= _PAGE_PRESENT | _PAGE_RW;
                if (type == GTT_TYPE_PPGTT_PDE_PT)
                        se.val64 |= PPAT_CACHED;

                for (i = 0; i < page_entry_num; i++)
                        ops->set_entry(scratch_pt, &se, i, false, 0, vgpu);
        }

        return 0;
}

static int release_scratch_page_tree(struct intel_vgpu *vgpu)
{
        int i;
        struct device *dev = &vgpu->gvt->dev_priv->drm.pdev->dev;
        dma_addr_t daddr;

        for (i = GTT_TYPE_PPGTT_PTE_PT; i < GTT_TYPE_MAX; i++) {
                if (vgpu->gtt.scratch_pt[i].page != NULL) {
                        daddr = (dma_addr_t)(vgpu->gtt.scratch_pt[i].page_mfn <<
                                        I915_GTT_PAGE_SHIFT);
                        dma_unmap_page(dev, daddr, 4096, PCI_DMA_BIDIRECTIONAL);
                        __free_page(vgpu->gtt.scratch_pt[i].page);
                        vgpu->gtt.scratch_pt[i].page = NULL;
                        vgpu->gtt.scratch_pt[i].page_mfn = 0;
                }
        }

        return 0;
}

static int create_scratch_page_tree(struct intel_vgpu *vgpu)
{
        int i, ret;

        for (i = GTT_TYPE_PPGTT_PTE_PT; i < GTT_TYPE_MAX; i++) {
                ret = alloc_scratch_pages(vgpu, i);
                if (ret)
                        goto err;
        }

        return 0;

err:
        release_scratch_page_tree(vgpu);
        return ret;
}

/**
 * intel_vgpu_init_gtt - initialize per-vGPU graphics memory virulization
 * @vgpu: a vGPU
 *
 * This function is used to initialize per-vGPU graphics memory virtualization
 * components.
 *
 * Returns:
 * Zero on success, error code if failed.
 */
int intel_vgpu_init_gtt(struct intel_vgpu *vgpu)
{
        struct intel_vgpu_gtt *gtt = &vgpu->gtt;
        struct intel_vgpu_mm *ggtt_mm;

        hash_init(gtt->tracked_guest_page_hash_table);
        hash_init(gtt->shadow_page_hash_table);

        INIT_LIST_HEAD(&gtt->mm_list_head);
        INIT_LIST_HEAD(&gtt->oos_page_list_head);
        INIT_LIST_HEAD(&gtt->post_shadow_list_head);

        intel_vgpu_reset_ggtt(vgpu);

        ggtt_mm = intel_vgpu_create_mm(vgpu, INTEL_GVT_MM_GGTT,
                        NULL, 1, 0);
        if (IS_ERR(ggtt_mm)) {
                gvt_vgpu_err("fail to create mm for ggtt.\n");
                return PTR_ERR(ggtt_mm);
        }

        gtt->ggtt_mm = ggtt_mm;

        return create_scratch_page_tree(vgpu);
}

static void intel_vgpu_free_mm(struct intel_vgpu *vgpu, int type)
{
        struct list_head *pos, *n;
        struct intel_vgpu_mm *mm;

        list_for_each_safe(pos, n, &vgpu->gtt.mm_list_head) {
                mm = container_of(pos, struct intel_vgpu_mm, list);
                if (mm->type == type) {
                        vgpu->gvt->gtt.mm_free_page_table(mm);
                        list_del(&mm->list);
                        list_del(&mm->lru_list);
                        kfree(mm);
                }
        }
}

/**
 * intel_vgpu_clean_gtt - clean up per-vGPU graphics memory virulization
 * @vgpu: a vGPU
 *
 * This function is used to clean up per-vGPU graphics memory virtualization
 * components.
 *
 * Returns:
 * Zero on success, error code if failed.
 */
void intel_vgpu_clean_gtt(struct intel_vgpu *vgpu)
{
        ppgtt_free_all_shadow_page(vgpu);
        release_scratch_page_tree(vgpu);

        intel_vgpu_free_mm(vgpu, INTEL_GVT_MM_PPGTT);
        intel_vgpu_free_mm(vgpu, INTEL_GVT_MM_GGTT);
}

static void clean_spt_oos(struct intel_gvt *gvt)
{
        struct intel_gvt_gtt *gtt = &gvt->gtt;
        struct list_head *pos, *n;
        struct intel_vgpu_oos_page *oos_page;

        WARN(!list_empty(&gtt->oos_page_use_list_head),
                "someone is still using oos page\n");

        list_for_each_safe(pos, n, &gtt->oos_page_free_list_head) {
                oos_page = container_of(pos, struct intel_vgpu_oos_page, list);
                list_del(&oos_page->list);
                kfree(oos_page);
        }
}

static int setup_spt_oos(struct intel_gvt *gvt)
{
        struct intel_gvt_gtt *gtt = &gvt->gtt;
        struct intel_vgpu_oos_page *oos_page;
        int i;
        int ret;

        INIT_LIST_HEAD(&gtt->oos_page_free_list_head);
        INIT_LIST_HEAD(&gtt->oos_page_use_list_head);

        for (i = 0; i < preallocated_oos_pages; i++) {
                oos_page = kzalloc(sizeof(*oos_page), GFP_KERNEL);
                if (!oos_page) {
                        ret = -ENOMEM;
                        goto fail;
                }

                INIT_LIST_HEAD(&oos_page->list);
                INIT_LIST_HEAD(&oos_page->vm_list);
                oos_page->id = i;
                list_add_tail(&oos_page->list, &gtt->oos_page_free_list_head);
        }

        gvt_dbg_mm("%d oos pages preallocated\n", i);

        return 0;
fail:
        clean_spt_oos(gvt);
        return ret;
}

/**
 * intel_vgpu_find_ppgtt_mm - find a PPGTT mm object
 * @vgpu: a vGPU
 * @page_table_level: PPGTT page table level
 * @root_entry: PPGTT page table root pointers
 *
 * This function is used to find a PPGTT mm object from mm object pool
 *
 * Returns:
 * pointer to mm object on success, NULL if failed.
 */
struct intel_vgpu_mm *intel_vgpu_find_ppgtt_mm(struct intel_vgpu *vgpu,
                int page_table_level, void *root_entry)
{
        struct list_head *pos;
        struct intel_vgpu_mm *mm;
        u64 *src, *dst;

        list_for_each(pos, &vgpu->gtt.mm_list_head) {
                mm = container_of(pos, struct intel_vgpu_mm, list);
                if (mm->type != INTEL_GVT_MM_PPGTT)
                        continue;

                if (mm->page_table_level != page_table_level)
                        continue;

                src = root_entry;
                dst = mm->virtual_page_table;

                if (page_table_level == 3) {
                        if (src[0] == dst[0]
                                        && src[1] == dst[1]
                                        && src[2] == dst[2]
                                        && src[3] == dst[3])
                                return mm;
                } else {
                        if (src[0] == dst[0])
                                return mm;
                }
        }
        return NULL;
}

/**
 * intel_vgpu_g2v_create_ppgtt_mm - create a PPGTT mm object from
 * g2v notification
 * @vgpu: a vGPU
 * @page_table_level: PPGTT page table level
 *
 * This function is used to create a PPGTT mm object from a guest to GVT-g
 * notification.
 *
 * Returns:
 * Zero on success, negative error code if failed.
 */
int intel_vgpu_g2v_create_ppgtt_mm(struct intel_vgpu *vgpu,
                int page_table_level)
{
        u64 *pdp = (u64 *)&vgpu_vreg64_t(vgpu, vgtif_reg(pdp[0]));
        struct intel_vgpu_mm *mm;

        if (WARN_ON((page_table_level != 4) && (page_table_level != 3)))
                return -EINVAL;

        mm = intel_vgpu_find_ppgtt_mm(vgpu, page_table_level, pdp);
        if (mm) {
                intel_gvt_mm_reference(mm);
        } else {
                mm = intel_vgpu_create_mm(vgpu, INTEL_GVT_MM_PPGTT,
                                pdp, page_table_level, 0);
                if (IS_ERR(mm)) {
                        gvt_vgpu_err("fail to create mm\n");
                        return PTR_ERR(mm);
                }
        }
        return 0;
}

/**
 * intel_vgpu_g2v_destroy_ppgtt_mm - destroy a PPGTT mm object from
 * g2v notification
 * @vgpu: a vGPU
 * @page_table_level: PPGTT page table level
 *
 * This function is used to create a PPGTT mm object from a guest to GVT-g
 * notification.
 *
 * Returns:
 * Zero on success, negative error code if failed.
 */
int intel_vgpu_g2v_destroy_ppgtt_mm(struct intel_vgpu *vgpu,
                int page_table_level)
{
        u64 *pdp = (u64 *)&vgpu_vreg64_t(vgpu, vgtif_reg(pdp[0]));
        struct intel_vgpu_mm *mm;

        if (WARN_ON((page_table_level != 4) && (page_table_level != 3)))
                return -EINVAL;

        mm = intel_vgpu_find_ppgtt_mm(vgpu, page_table_level, pdp);
        if (!mm) {
                gvt_vgpu_err("fail to find ppgtt instance.\n");
                return -EINVAL;
        }
        intel_gvt_mm_unreference(mm);
        return 0;
}

/**
 * intel_gvt_init_gtt - initialize mm components of a GVT device
 * @gvt: GVT device
 *
 * This function is called at the initialization stage, to initialize
 * the mm components of a GVT device.
 *
 * Returns:
 * zero on success, negative error code if failed.
 */
int intel_gvt_init_gtt(struct intel_gvt *gvt)
{
        int ret;
        void *page;
        struct device *dev = &gvt->dev_priv->drm.pdev->dev;
        dma_addr_t daddr;

        gvt_dbg_core("init gtt\n");

        if (IS_BROADWELL(gvt->dev_priv) || IS_SKYLAKE(gvt->dev_priv)
                || IS_KABYLAKE(gvt->dev_priv)) {
                gvt->gtt.pte_ops = &gen8_gtt_pte_ops;
                gvt->gtt.gma_ops = &gen8_gtt_gma_ops;
                gvt->gtt.mm_alloc_page_table = gen8_mm_alloc_page_table;
                gvt->gtt.mm_free_page_table = gen8_mm_free_page_table;
        } else {
                return -ENODEV;
        }

        page = (void *)get_zeroed_page(GFP_KERNEL);
        if (!page) {
                gvt_err("fail to allocate scratch ggtt page\n");
                return -ENOMEM;
        }

        daddr = dma_map_page(dev, virt_to_page(page), 0,
                        4096, PCI_DMA_BIDIRECTIONAL);
        if (dma_mapping_error(dev, daddr)) {
                gvt_err("fail to dmamap scratch ggtt page\n");
                __free_page(virt_to_page(page));
                return -ENOMEM;
        }

        gvt->gtt.scratch_page = virt_to_page(page);
        gvt->gtt.scratch_mfn = (unsigned long)(daddr >> I915_GTT_PAGE_SHIFT);

        if (enable_out_of_sync) {
                ret = setup_spt_oos(gvt);
                if (ret) {
                        gvt_err("fail to initialize SPT oos\n");
                        dma_unmap_page(dev, daddr, 4096, PCI_DMA_BIDIRECTIONAL);
                        __free_page(gvt->gtt.scratch_page);
                        return ret;
                }
        }
        INIT_LIST_HEAD(&gvt->gtt.mm_lru_list_head);
        return 0;
}

/**
 * intel_gvt_clean_gtt - clean up mm components of a GVT device
 * @gvt: GVT device
 *
 * This function is called at the driver unloading stage, to clean up the
 * the mm components of a GVT device.
 *
 */
void intel_gvt_clean_gtt(struct intel_gvt *gvt)
{
        struct device *dev = &gvt->dev_priv->drm.pdev->dev;
        dma_addr_t daddr = (dma_addr_t)(gvt->gtt.scratch_mfn <<
                                        I915_GTT_PAGE_SHIFT);

        dma_unmap_page(dev, daddr, 4096, PCI_DMA_BIDIRECTIONAL);

        __free_page(gvt->gtt.scratch_page);

        if (enable_out_of_sync)
                clean_spt_oos(gvt);
}

/**
 * intel_vgpu_reset_ggtt - reset the GGTT entry
 * @vgpu: a vGPU
 *
 * This function is called at the vGPU create stage
 * to reset all the GGTT entries.
 *
 */
void intel_vgpu_reset_ggtt(struct intel_vgpu *vgpu)
{
        struct intel_gvt *gvt = vgpu->gvt;
        struct drm_i915_private *dev_priv = gvt->dev_priv;
        struct intel_gvt_gtt_pte_ops *ops = vgpu->gvt->gtt.pte_ops;
        u32 index;
        u32 offset;
        u32 num_entries;
        struct intel_gvt_gtt_entry e;

        memset(&e, 0, sizeof(struct intel_gvt_gtt_entry));
        e.type = GTT_TYPE_GGTT_PTE;
        ops->set_pfn(&e, gvt->gtt.scratch_mfn);
        e.val64 |= _PAGE_PRESENT;

        index = vgpu_aperture_gmadr_base(vgpu) >> PAGE_SHIFT;
        num_entries = vgpu_aperture_sz(vgpu) >> PAGE_SHIFT;
        for (offset = 0; offset < num_entries; offset++)
                ops->set_entry(NULL, &e, index + offset, false, 0, vgpu);

        index = vgpu_hidden_gmadr_base(vgpu) >> PAGE_SHIFT;
        num_entries = vgpu_hidden_sz(vgpu) >> PAGE_SHIFT;
        for (offset = 0; offset < num_entries; offset++)
                ops->set_entry(NULL, &e, index + offset, false, 0, vgpu);

        gtt_invalidate(dev_priv);
}

/**
 * intel_vgpu_reset_gtt - reset the all GTT related status
 * @vgpu: a vGPU
 *
 * This function is called from vfio core to reset reset all
 * GTT related status, including GGTT, PPGTT, scratch page.
 *
 */
void intel_vgpu_reset_gtt(struct intel_vgpu *vgpu)
{
        ppgtt_free_all_shadow_page(vgpu);

        /* Shadow pages are only created when there is no page
         * table tracking data, so remove page tracking data after
         * removing the shadow pages.
         */
        intel_vgpu_free_mm(vgpu, INTEL_GVT_MM_PPGTT);

        intel_vgpu_reset_ggtt(vgpu);
}