Re: [PATCH v3 18/62] KVM: SVM: Disable (x2)AVIC IPI virtualization if CPU has erratum #1235

[Sean Christopherson]

On Mon, Jun 23, 2025, Naveen N Rao wrote:
> On Wed, Jun 11, 2025 at 03:45:21PM -0700, Sean Christopherson wrote:
> > diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
> > index 48c737e1200a..bf8b59556373 100644
> > --- a/arch/x86/kvm/svm/avic.c
> > +++ b/arch/x86/kvm/svm/avic.c
> > @@ -1187,6 +1187,14 @@ bool avic_hardware_setup(void)
> >  	if (x2avic_enabled)
> >  		pr_info("x2AVIC enabled\n");
> >  
> > +	/*
> > +	 * Disable IPI virtualization for AMD Family 17h CPUs (Zen1 and Zen2)
> > +	 * due to erratum 1235, which results in missed GA log events and thus
> 							^^^^^^^^^^^^^
> Not sure I understand the reference to GA log events here -- those are 
> only for device interrupts and not IPIs.

Doh, you're absolutely right.  I'll fix to this when applying:

	/*
	 * Disable IPI virtualization for AMD Family 17h CPUs (Zen1 and Zen2)
	 * due to erratum 1235, which results in missed VM-Exits on the sender
	 * and thus missed wake events for blocking vCPUs due to the CPU
	 * failing to see a software update to clear IsRunning.
	 */