From 6f43ed01e87c8a8dbd8c826eaf0f714c1342c039 Mon Sep 17 00:00:00 2001 From: Nadav Amit Date: Tue, 15 Jul 2014 17:37:46 +0300 Subject: KVM: x86: DR6/7.RTM cannot be written Haswell and newer Intel CPUs have support for RTM, and in that case DR6.RTM is not fixed to 1 and DR7.RTM is not fixed to zero. That is not the case in the current KVM implementation. This bug is apparent only if the MOV-DR instruction is emulated or the host also debugs the guest. This patch is a partial fix which enables DR6.RTM and DR7.RTM to be cleared and set respectively. It also sets DR6.RTM upon every debug exception. Obviously, it is not a complete fix, as debugging of RTM is still unsupported. Signed-off-by: Nadav Amit Signed-off-by: Paolo Bonzini --- arch/x86/kvm/cpuid.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'arch/x86/kvm/cpuid.h') diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h index f9087315e0cd..a5380590ab0e 100644 --- a/arch/x86/kvm/cpuid.h +++ b/arch/x86/kvm/cpuid.h @@ -95,4 +95,12 @@ static inline bool guest_cpuid_has_gbpages(struct kvm_vcpu *vcpu) best = kvm_find_cpuid_entry(vcpu, 0x80000001, 0); return best && (best->edx & bit(X86_FEATURE_GBPAGES)); } + +static inline bool guest_cpuid_has_rtm(struct kvm_vcpu *vcpu) +{ + struct kvm_cpuid_entry2 *best; + + best = kvm_find_cpuid_entry(vcpu, 7, 0); + return best && (best->ebx & bit(X86_FEATURE_RTM)); +} #endif -- cgit v1.2.3