Re: [PATCH v2 3/4] x86/bugs: KVM: Add support for SRSO_MSR_FIX

Borislav Petkov
2025-01-08T19:15:08Z

On Wed, Jan 08, 2025 at 10:37:57AM -0800, Jim Mattson wrote:
> Surely, IBPB-on-VMexit is worse for performance than safe-RET?!?

We don't need safe-RET with SRSO_USER_KERNEL_NO=1. And there's no safe-RET for
virt only. So IBPB-on-VMEXIT is the next best thing. The good thing is, those
machines have BpSpecReduce too so you won't be doing IBPB-on-VMEXIT either but
what we're talking about here - BpSpecReduce.

--
Regards/Gruss,
Boris.