From b5e2fec0ebc3fcaff954092bb69444a67a904c0a Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Tue, 22 Jul 2008 08:00:45 +0200 Subject: [PATCH] KVM: Ignore DEBUGCTL MSRs with no effect Netware writes to DEBUGCTL and reads from the DEBUGCTL and LAST*IP MSRs without further checks and is really confused to receive a #GP during that. To make it happy we should just make them stubs, which is exactly what SVM already does. Writes to DEBUGCTL that are vendor-specific are resembled to behave as if the virtual CPU does not know them. Signed-off-by: Alexander Graf Signed-off-by: Avi Kivity --- arch/x86/kvm/x86.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 5620df2685db..94a216562f10 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -665,6 +665,18 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) pr_unimpl(vcpu, "%s: MSR_IA32_MCG_CTL 0x%llx, nop\n", __func__, data); break; + case MSR_IA32_DEBUGCTLMSR: + if (!data) { + /* We support the non-activated case already */ + break; + } else if (data & ~(DEBUGCTLMSR_LBR | DEBUGCTLMSR_BTF)) { + /* Values other than LBR and BTF are vendor-specific, + thus reserved and should throw a #GP */ + return 1; + } + pr_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n", + __func__, data); + break; case MSR_IA32_UCODE_REV: case MSR_IA32_UCODE_WRITE: break; @@ -757,6 +769,11 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) case MSR_IA32_MC0_MISC+16: case MSR_IA32_UCODE_REV: case MSR_IA32_EBL_CR_POWERON: + case MSR_IA32_DEBUGCTLMSR: + case MSR_IA32_LASTBRANCHFROMIP: + case MSR_IA32_LASTBRANCHTOIP: + case MSR_IA32_LASTINTFROMIP: + case MSR_IA32_LASTINTTOIP: data = 0; break; case MSR_MTRRcap: -- GitLab