Commit f046923a authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

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



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: b901b252 ("drm/i915/gvt: Add 2M huge gtt support")
Reviewed-by: default avatarYan Zhao <yan.y.zhao@intel.com>
Tested-by: default avatarYongwei Ma <yongwei.ma@intel.com>
Reviewed-by: default avatarZhi Wang <zhi.a.wang@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-2-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 52e322ed

drivers/gpu/drm/i915/gvt/gtt.c

+4 −0
Original line number Diff line number Diff line
@@ -1183,6 +1183,10 @@ 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));

}