KVM: x86: Fix device passthrough when SME is active

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@vger.kernel.org> # 4.14.x-
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index f551962ac294..763bb3bade63 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2770,8 +2770,10 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
         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) {