Messages in this thread | | | Subject | Re: [PATCH 4/5] KVM: vmx: implement MSR_IA32_TSX_CTRL disable RTM functionality | From | Paolo Bonzini <> | Date | Thu, 5 Dec 2019 11:16:16 +0100 |
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On 05/12/19 00:49, Jim Mattson wrote: >> if (!boot_cpu_has(X86_FEATURE_RTM)) >> - data &= ~ARCH_CAP_TAA_NO; >> + data &= ~(ARCH_CAP_TAA_NO | ARCH_CAP_TSX_CTRL_MSR); >> else if (!boot_cpu_has_bug(X86_BUG_TAA)) >> data |= ARCH_CAP_TAA_NO; >> - else if (data & ARCH_CAP_TSX_CTRL_MSR) >> - data &= ~ARCH_CAP_MDS_NO; >> >> - /* KVM does not emulate MSR_IA32_TSX_CTRL. */ >> - data &= ~ARCH_CAP_TSX_CTRL_MSR; > Shouldn't kvm be masking off any bits that it doesn't know about here? > Who knows what future features we may claim to support?
Good question, in the past the ARCH_CAPABILITIES were just "we don't have this bug" so it made sense to pass everything through. Now we have TSX_CTRL that is of a different kind and arguably should have been a CPUID bit, so we should indeed mask unknown capabilties.
Paolo
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