From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
chengkev@google.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, pbonzini@redhat.com,
yosry.ahmed@linux.dev
Subject: Re: [PATCH 2/2] KVM: SVM: Raise #UD if VMMCALL instruction is not intercepted
Date: Tue, 6 Jan 2026 20:40:27 +0000 [thread overview]
Message-ID: <29ea5ead-1ee3-4ecd-ad4a-63fd99a7f67f@citrix.com> (raw)
In-Reply-To: <aV1bC3Wk-LbP1hUZ@google.com>
On 06/01/2026 6:57 pm, Sean Christopherson wrote:
> On Tue, Jan 06, 2026, Andrew Cooper wrote:
>>> Mentioning L2 and L1 is confusing. It reads like arbitrary KVM behavior. And
>>> IMO the most notable thing is what's missing: an intercept check. _That_ is
>>> worth commenting, e.g.
>>>
>>> /*
>>> * VMMCALL #UDs if it's not intercepted, and KVM reaches this point if
>>> * and only if the VMCALL intercept is not set in vmcb12.
>>> */
>> Not intercepting VMMCALL is stated to be an unconditional VMRUN
>> failure. APM Vol3 15.5 Canonicalization and Consistency Checks.
> Hrm, I can't find that. I see:
>
> The VMRUN intercept bit is clear.
>
> but I don't see anything about VMMCALL being a mandatory intercept.
Gah. I even double checked before sending, but I'm apparently
completely blind to the difference between VMRUN and VMMCALL.
Sorry for the noise.
~Andrew
next prev parent reply other threads:[~2026-01-06 20:40 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-06 4:12 [PATCH 0/2] KVM: SVM: Align SVM with APM defined behaviors Kevin Cheng
2026-01-06 4:12 ` [PATCH 1/2] KVM: SVM: Generate #UD for certain instructions when SVME.EFER is disabled Kevin Cheng
2026-01-06 18:21 ` Sean Christopherson
2026-01-06 20:38 ` Andrew Cooper
2026-01-06 23:42 ` Yosry Ahmed
2026-01-06 23:48 ` Sean Christopherson
2026-01-07 0:04 ` Yosry Ahmed
2026-01-06 4:12 ` [PATCH 2/2] KVM: SVM: Raise #UD if VMMCALL instruction is not intercepted Kevin Cheng
2026-01-06 18:29 ` Sean Christopherson
2026-01-06 18:52 ` Andrew Cooper
2026-01-06 18:57 ` Sean Christopherson
2026-01-06 20:40 ` Andrew Cooper [this message]
2026-01-06 23:31 ` Yosry Ahmed
2026-01-06 23:38 ` Sean Christopherson
2026-01-07 0:02 ` Yosry Ahmed
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