Re: [PATCH 1/2] KVM: SVM: Fix TSC_AUX virtualization setup

[Sean Christopherson]

On Fri, Sep 15, 2023, Tom Lendacky wrote:
> On 9/14/23 16:13, Sean Christopherson wrote:
> This toggling possibility raises a question related to the second patch in
> this series that eliminates the use of the user return MSR for TSC_AUX.
> Depending on when the interfaces are called (set CPUID, host-initiated WRMSR
> of TSC_AUX, set CPUID again), I think we could end up in a state where the
> host TSC_AUX may not get restored properly, not 100% sure at the moment,
> though.

Give me a few minutes to respond to patch 2, I think it can be much simpler, more
performant, and avoid any races.

> Let me drop that patch from the series for now and just send the fix(es).
> I'll work through the other scenarios and code paths and send the user
> return MSR optimization as a separate series later.