Re: [PATCH v2] KVM: VMX: Handle bad values on proxied writes to LBR MSRs

[Sean Christopherson]

On Tue, 26 May 2026 19:26:17 -0700, Sean Christopherson wrote:
> Use the "safe" WRMSR API when writing LBRs on behalf of the guest (or host
> userspace), and propagate any errors back to the instigator, as the value
> being written is untrusted.  E.g. if the guest (or host userspace) attempts
> to set reserved bits in LBR_SELECT, then KVM needs to return an error, and
> not WARN on the bad value.
> 
> Continue using the "unsafe" version of RDMSR, as it should be impossible to
> reach the helper with a completely bogus MSR, i.e. WARNing on RDMSR failure
> is very desirable, e.g. to make KVM bugs more visible.
> 
> [...]

Applied to kvm-x86 vmx, thanks!

[1/1] KVM: VMX: Handle bad values on proxied writes to LBR MSRs
      https://github.com/kvm-x86/linux/commit/ca674df13b19

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