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From: Sean Christopherson <seanjc@google.com>
To: Binbin Wu <binbin.wu@linux.intel.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	pbonzini@redhat.com,  rick.p.edgecombe@intel.com,
	xiaoyao.li@intel.com, chao.gao@intel.com,  kai.huang@intel.com
Subject: Re: [RFC PATCH v2 1/4] KVM: x86: TDX: Track supported configurable CPUID bits
Date: Mon, 29 Jun 2026 17:37:21 -0700	[thread overview]
Message-ID: <akMPwaQ9nFDnGbYg@google.com> (raw)
In-Reply-To: <e6515066-3768-459d-8ae4-82c0243556a1@linux.intel.com>

On Mon, Jun 29, 2026, Binbin Wu wrote:
> On 6/26/2026 1:04 AM, Sean Christopherson wrote:
> > On Thu, Jun 04, 2026, Binbin Wu wrote:
> > CPUID.0x1E is a bit different because it's kinda sorta a feature?  That one is
> > probably worth restricting, but again that's easy to do in a case-statement.
> 
> Only CPUID.0x1E.EAX has TDX directly configurable bits currently, no special
> handling needed for the rest of CPUID.0x1E.

But isn't the whole point to guard against TDX Modules gaining support for features
KVM doesn't know about?  What happens if hardware extends into CPUID.0x1E.ECX,
and the TDX Module follows suit?

I guess that applies to all the feature leaves?

  reply	other threads:[~2026-06-30  0:37 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-04  2:33 [RFC PATCH v2 0/4] KVM: x86: TDX: Validate directly configurable CPUID bits Binbin Wu
2026-06-04  2:33 ` [RFC PATCH v2 1/4] KVM: x86: TDX: Track supported " Binbin Wu
2026-06-25 17:04   ` Sean Christopherson
2026-06-29  3:02     ` Binbin Wu
2026-06-30  0:37       ` Sean Christopherson [this message]
2026-06-30  2:10         ` Binbin Wu
2026-06-04  2:33 ` [RFC PATCH v2 2/4] KVM: x86: TDX: Hide unsupported " Binbin Wu
2026-06-04  2:33 ` [RFC PATCH v2 3/4] KVM: x86: TDX: Validate userspace CPUID input for KVM_TDX_INIT_VM Binbin Wu
2026-06-04  2:33 ` [RFC PATCH v2 4/4] KVM: x86: TDX: Report CORE_CAPABILITIES as supported Binbin Wu
2026-06-04  6:53   ` Xiaoyao Li
2026-06-04  7:20     ` Binbin Wu
2026-06-22  6:32 ` [RFC PATCH v2 0/4] KVM: x86: TDX: Validate directly configurable CPUID bits Binbin Wu
2026-06-25 17:04   ` Sean Christopherson
2026-06-29  3:02     ` Binbin Wu

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