From 606decd67049217684e3cb5a54104d51ddd4ef35 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 1 Oct 2015 13:12:47 +0200 Subject: 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 --- arch/x86/kvm/svm.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'arch/x86/kvm/svm.c') 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) && -- cgit 1.4.1