Re: [PATCH 1/5] KVM: x86: fix presentation of TSX feature in ARCH_CAPABILITIES

On Mon, Nov 18, 2019 at 10:17 AM Paolo Bonzini pbonzini@redhat.com wrote:

KVM does not implement MSR_IA32_TSX_CTRL, so it must not be presented to the guests. It is also confusing to have !ARCH_CAP_TSX_CTRL_MSR && !RTM && ARCH_CAP_TAA_NO: lack of MSR_IA32_TSX_CTRL suggests TSX was not hidden (it actually was), yet the value says that TSX is not vulnerable to microarchitectural data sampling. Fix both.

I actually think kvm should virtualize IA32_TSX_CTRL for VMs that have exclusive use of their cores (i.e. the same VMs for which we disable MWAIT and HLT exiting).