linux-kernel - Re: [PATCH 1/2] KVM: x86/mmu: Add RET_PF_RETRY_INVALID

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Message-ID: <34609df5b649ca9f53dfe6f5a134445f1c17279a.camel@intel.com>
Date: Mon, 19 May 2025 15:22:25 +0000
From: "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
To: "Chatre, Reinette" <reinette.chatre@...el.com>, "seanjc@...gle.com"
	<seanjc@...gle.com>, "Zhao, Yan Y" <yan.y.zhao@...el.com>
CC: "kvm@...r.kernel.org" <kvm@...r.kernel.org>, "pbonzini@...hat.com"
	<pbonzini@...hat.com>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] KVM: x86/mmu: Add RET_PF_RETRY_INVALID_SLOT for fault
 retry on invalid slot

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.