Re: [PATCH 1/2] KVM: x86/mmu: Add RET_PF_RETRY_INVALID_SLOT for fault retry on invalid slot

[Sean Christopherson <seanjc@google.com>]

On Mon, May 19, 2025, Rick P Edgecombe wrote:
> On Mon, 2025-05-19 at 08:05 -0700, Reinette Chatre wrote:
> > > Was this hit by a real VMM?  If so, why is a TDX VMM removing a memslot
> > > without kicking vCPUs out of KVM?
> > 
> > No, this was not hit by a real VMM. This was hit by a TDX MMU stress test
> > (built on top of [1]) that is still under development.
> 
> Yea, the context is that this TDX MMU stress test has grown more and more
> stressful. Mostly it has found TDX module issues. But recently it added this
> case which turned out to be a general issue. The TDX specific MMU stress test is
> not ready yet, so Yan added the case to the general test and fixed it for both
> VM types.
> 
> For TDX, since it's an pretty edge case and nothing catastrophic happens, I'd
> prefer to not rush a fix into the TDX PR.

Yeah, and I'd prefer not to bleed these details into userspace (or into KVM in
general), hence my question about whether or not a "real" VMM hit this.

Thanks!