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drm/i915/gvt: Verify pfn is "valid" before dereferencing "struct page"

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[ Upstream commit f046923af7 ]

Check that the pfn found by gfn_to_pfn() is actually backed by "struct
page" memory prior to retrieving and dereferencing the page.  KVM
supports backing guest memory with VM_PFNMAP, VM_IO, etc., and so
there is no guarantee the pfn returned by gfn_to_pfn() has an associated
"struct page".

Fixes: b901b252b6 ("drm/i915/gvt: Add 2M huge gtt support")
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Sean Christopherson
2023-07-28 18:35:07 -07:00
committed by Greg Kroah-Hartman
parent 6436973164
commit f5738399ed
1 changed files with 4 additions and 0 deletions
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4
drivers/gpu/drm/i915/gvt/gtt.c
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@@ -1188,6 +1188,10 @@ static int is_2MB_gtt_possible(struct intel_vgpu *vgpu,
pfn = gfn_to_pfn(vgpu->vfio_device.kvm, ops->get_pfn(entry));
if (is_error_noslot_pfn(pfn))
return -EINVAL;
if (!pfn_valid(pfn))
return -EINVAL;
return PageTransHuge(pfn_to_page(pfn));
}