Return struct page instead of pfn from gfn_to_mfn. This function is only
used to determine if the page is a transparent hugepage, to enable 2MB
huge gtt shadowing. Returning the page directly avoids the risk of
calling pfn_to_page on a VM_IO|VM_PFNMAP pfn.

This change also properly releases the reference on the page returned by
gfn_to_pfn.

Signed-off-by: David Stevens <redacted>
---
 drivers/gpu/drm/i915/gvt/gtt.c       | 12 ++++++++----
 drivers/gpu/drm/i915/gvt/hypercall.h |  3 ++-
 drivers/gpu/drm/i915/gvt/kvmgt.c     | 12 ++++--------
 drivers/gpu/drm/i915/gvt/mpt.h       |  8 ++++----
 4 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
index 9478c132d7b6..b2951c560582 100644
--- a/drivers/gpu/drm/i915/gvt/gtt.c
+++ b/drivers/gpu/drm/i915/gvt/gtt.c

@@ -1160,16 +1160,20 @@ static int is_2MB_gtt_possible(struct intel_vgpu *vgpu,
        struct intel_gvt_gtt_entry *entry)
 {
        struct intel_gvt_gtt_pte_ops *ops = vgpu->gvt->gtt.pte_ops;
-       unsigned long pfn;
+       struct page *page;
+       bool is_trans_huge;

        if (!HAS_PAGE_SIZES(vgpu->gvt->gt->i915, I915_GTT_PAGE_SIZE_2M))
                return 0;

-       pfn = intel_gvt_hypervisor_gfn_to_mfn(vgpu, ops->get_pfn(entry));
-       if (pfn == INTEL_GVT_INVALID_ADDR)
+       page = intel_gvt_hypervisor_gfn_to_mfn_page(vgpu, ops->get_pfn(entry));
+       if (!page)
                return -EINVAL;

-       return PageTransHuge(pfn_to_page(pfn));
+       is_trans_huge = PageTransHuge(page);
+       put_page(page);
+
+       return is_trans_huge;
 }

 static int split_2MB_gtt_entry(struct intel_vgpu *vgpu,

diff --git a/drivers/gpu/drm/i915/gvt/hypercall.h b/drivers/gpu/drm/i915/gvt/hypercall.h
index b79da5124f83..017190ff52d5 100644
--- a/drivers/gpu/drm/i915/gvt/hypercall.h
+++ b/drivers/gpu/drm/i915/gvt/hypercall.h

@@ -60,7 +60,8 @@ struct intel_gvt_mpt {
                        unsigned long len);
        int (*write_gpa)(unsigned long handle, unsigned long gpa, void *buf,
                         unsigned long len);
-       unsigned long (*gfn_to_mfn)(unsigned long handle, unsigned long gfn);
+       struct page *(*gfn_to_mfn_page)(unsigned long handle,
+                                       unsigned long gfn);

        int (*dma_map_guest_page)(unsigned long handle, unsigned long gfn,
                                  unsigned long size, dma_addr_t *dma_addr);

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index b829ff67e3d9..1e97ae813ed0 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c

@@ -1928,21 +1928,17 @@ static int kvmgt_inject_msi(unsigned long handle, u32 addr, u16 data)
        return -EFAULT;
 }

-static unsigned long kvmgt_gfn_to_pfn(unsigned long handle, unsigned long gfn)
+static struct page *kvmgt_gfn_to_page(unsigned long handle, unsigned long gfn)
 {
        struct kvmgt_guest_info *info;
        kvm_pfn_t pfn;

        if (!handle_valid(handle))
-               return INTEL_GVT_INVALID_ADDR;
+               return NULL;

        info = (struct kvmgt_guest_info *)handle;

-       pfn = kvm_pfn_page_unwrap(gfn_to_pfn(info->kvm, gfn));
-       if (is_error_noslot_pfn(pfn))
-               return INTEL_GVT_INVALID_ADDR;
-
-       return pfn;
+       return gfn_to_pfn(info->kvm, gfn).page;
 }

 static int kvmgt_dma_map_guest_page(unsigned long handle, unsigned long gfn,

@@ -2112,7 +2108,7 @@ static const struct intel_gvt_mpt kvmgt_mpt = {
        .disable_page_track = kvmgt_page_track_remove,
        .read_gpa = kvmgt_read_gpa,
        .write_gpa = kvmgt_write_gpa,
-       .gfn_to_mfn = kvmgt_gfn_to_pfn,
+       .gfn_to_mfn_page = kvmgt_gfn_to_page,
        .dma_map_guest_page = kvmgt_dma_map_guest_page,
        .dma_unmap_guest_page = kvmgt_dma_unmap_guest_page,
        .dma_pin_guest_page = kvmgt_dma_pin_guest_page,

diff --git a/drivers/gpu/drm/i915/gvt/mpt.h b/drivers/gpu/drm/i915/gvt/mpt.h
index 550a456e936f..9169b83cf0f6 100644
--- a/drivers/gpu/drm/i915/gvt/mpt.h
+++ b/drivers/gpu/drm/i915/gvt/mpt.h

@@ -214,17 +214,17 @@ static inline int intel_gvt_hypervisor_write_gpa(struct intel_vgpu *vgpu,
 }

 /**
- * intel_gvt_hypervisor_gfn_to_mfn - translate a GFN to MFN
+ * intel_gvt_hypervisor_gfn_to_mfn_page - translate a GFN to MFN page
  * @vgpu: a vGPU
  * @gpfn: guest pfn
  *
  * Returns:
- * MFN on success, INTEL_GVT_INVALID_ADDR if failed.
+ * struct page* on success, NULL if failed.
  */
-static inline unsigned long intel_gvt_hypervisor_gfn_to_mfn(
+static inline unsigned long intel_gvt_hypervisor_gfn_to_mfn_page(
                struct intel_vgpu *vgpu, unsigned long gfn)
 {
-       return intel_gvt_host.mpt->gfn_to_mfn(vgpu->handle, gfn);
+       return intel_gvt_host.mpt->gfn_to_mfn_page(vgpu->handle, gfn);
 }

 /**
--

2.32.0.93.g670b81a890-goog