[PATCH 4.15 08/52] KVM: x86: Fix device passthrough when SME is active

[Greg Kroah-Hartman]

4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tom Lendacky <thomas.lendacky@xxxxxxx>

commit daaf216c06fba4ee4dc3f62715667da929d68774 upstream.

When using device passthrough with SME active, the MMIO range that is
mapped for the device should not be mapped encrypted.  Add a check in
set_spte() to insure that a page is not mapped encrypted if that page
is a device MMIO page as indicated by kvm_is_mmio_pfn().

Cc: <stable@xxxxxxxxxxxxxxx> # 4.14.x-
Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/x86/kvm/mmu.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2758,8 +2758,10 @@ static int set_spte(struct kvm_vcpu *vcp
 	else
 		pte_access &= ~ACC_WRITE_MASK;
 
+	if (!kvm_is_mmio_pfn(pfn))
+		spte |= shadow_me_mask;
+
 	spte |= (u64)pfn << PAGE_SHIFT;
-	spte |= shadow_me_mask;
 
 	if (pte_access & ACC_WRITE_MASK) {