linux-kernel - Re: [PATCH 2/4] KVM: x86: Advertise AMX CPUIDs in subleaf 0x1E.0x1 to userspace

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Message-ID: <aXXMIFNoy7cUu+3o@intel.com>
Date: Sun, 25 Jan 2026 15:54:08 +0800
From: Zhao Liu <zhao1.liu@...el.com>
To: Sean Christopherson <seanjc@...gle.com>
Cc: 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>,
	Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org, Chao Gao <chao.gao@...el.com>,
	Xudong Hao <xudong.hao@...el.com>
Subject: Re: [PATCH 2/4] KVM: x86: Advertise AMX CPUIDs in subleaf 0x1E.0x1
 to userspace

On Fri, Jan 23, 2026 at 10:06:32AM -0800, Sean Christopherson wrote:
> Date: Fri, 23 Jan 2026 10:06:32 -0800
> From: Sean Christopherson <seanjc@...gle.com>
> Subject: Re: [PATCH 2/4] KVM: x86: Advertise AMX CPUIDs in subleaf 0x1E.0x1
>  to userspace
> 
> On Thu, Nov 20, 2025, Zhao Liu wrote:
> > Define and pass AMX CPUIDs (0x1E.0x1) through to userspace.
> 
> Similar to the PASSTHROUGH_F() thing in the first patch, these aren't strictly
> being passed through.  In practice, they are passed through as of the current
> code base due to the features residing in KVM-only words, but I'd like to avoid
> stating that features are being passed through unless KVM very deliberately wants
> to ignore the kernel.

Good point, thanks for your reminder!

> As before, I'll tweak when applying.  Same goes for patches 3 and 4.

Thanks!

-Zhao