linux-kernel - Re: [PATCH v4 1/8] x86/bugs: Use VM_CLEAR_CPU

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Message-ID: <20251112180229.qmncwarn2w7edt3i@desk>
Date: Wed, 12 Nov 2025 10:02:29 -0800
From: Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>
To: Borislav Petkov <bp@...en8.de>
Cc: Sean Christopherson <seanjc@...gle.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Peter Zijlstra <peterz@...radead.org>,
	Josh Poimboeuf <jpoimboe@...nel.org>, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org, Brendan Jackman <jackmanb@...gle.com>
Subject: Re: [PATCH v4 1/8] x86/bugs: Use VM_CLEAR_CPU_BUFFERS in VMX as well

On Fri, Nov 07, 2025 at 07:59:41PM +0100, Borislav Petkov wrote:
> On Thu, Oct 30, 2025 at 05:30:33PM -0700, Sean Christopherson wrote:
> > From: Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>
> > 
> > TSA mitigation:
> > 
> >   d8010d4ba43e ("x86/bugs: Add a Transient Scheduler Attacks mitigation")
> > 
> > introduced VM_CLEAR_CPU_BUFFERS for guests on AMD CPUs. Currently on Intel
> > CLEAR_CPU_BUFFERS is being used for guests which has a much broader scope
> > (kernel->user also).
> > 
> > Make mitigations on Intel consistent with TSA. This would help handling the
> 
> "consistent" as in "use the VM-specific buffer clearing variant in VMX too"?

That's correct.

> In any case:
> 
> Acked-by: Borislav Petkov (AMD) <bp@...en8.de>

Thanks.