summary refs log tree commit diff
path: root/arch/x86/kvm/svm.c
diff options
context:
space:
mode:
authorPaolo Bonzini <pbonzini@redhat.com>2015-10-01 13:12:47 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2015-10-01 13:30:42 +0200
commit606decd67049217684e3cb5a54104d51ddd4ef35 (patch)
treecac2e61715bd29bdb93ab713b2764329d0d9b94a /arch/x86/kvm/svm.c
parent9bac175d8ed0b1dd3d3611c0713666b724eeace3 (diff)
downloadlinux-606decd67049217684e3cb5a54104d51ddd4ef35.tar.gz
Revert "KVM: x86: apply guest MTRR virtualization on host reserved pages"
This reverts commit fd717f11015f673487ffc826e59b2bad69d20fe5.
It was reported to cause Machine Check Exceptions (bug 104091).

Reported-by: harn-solo@gmx.de
Cc: stable@vger.kernel.org # 4.2+
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/svm.c')
-rw-r--r--arch/x86/kvm/svm.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 94b7d15db3fc..9e88078f4146 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1167,11 +1167,14 @@ static u64 svm_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
 	u8 mtrr;
 
 	/*
-	 * 1. MMIO: trust guest MTRR, so same as item 3.
+	 * 1. MMIO: always map as UC
 	 * 2. No passthrough: always map as WB, and force guest PAT to WB as well
 	 * 3. Passthrough: can't guarantee the result, try to trust guest.
 	 */
-	if (!is_mmio && !kvm_arch_has_assigned_device(vcpu->kvm))
+	if (is_mmio)
+		return _PAGE_NOCACHE;
+
+	if (!kvm_arch_has_assigned_device(vcpu->kvm))
 		return 0;
 
 	if (!kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_CD_NW_CLEARED) &&