linux-kernel - Re: [PATCH 0/2] KVM: SVM: Aggressively clear vmcb02 clean bits

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Message-ID: <aO11A4mzwqLzeXN9@google.com>
Date: Mon, 13 Oct 2025 14:54:11 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Jim Mattson <jmattson@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>, Thomas Gleixner <tglx@...utronix.de>, 
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, 
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, 
	"H. Peter Anvin" <hpa@...or.com>, kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/2] KVM: SVM: Aggressively clear vmcb02 clean bits

On Mon, Sep 22, 2025, Jim Mattson wrote:
> It is unlikely that L1 will toggle the MSR intercept bit in vmcb02,
> or that L1 will change its own IA32_PAT MSR. However, if it does,
> the affected fields in vmcb02 should not be marked clean.
> 
> An alternative approach would be to implement a set of mutators for
> vmcb02 fields, and to clear the associated clean bit whenever a field
> is modified.

Any reason not to tag these for stable@?  I can't think of any meaningful
downsides, so erring on the side of caution seems prudent.