From: Chao Gao <chao.gao@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Chang S. Bae" <chang.seok.bae@intel.com>,
kvm <kvm@vger.kernel.org>,
"Kernel Mailing List, Linux" <linux-kernel@vger.kernel.org>,
"Sean Christopherson" <seanjc@google.com>,
Zhao Liu <zhao1.liu@intel.com>
Subject: Re: [PATCH RFC v1 07/20] KVM: nVMX: Support the extended instruction info field
Date: Tue, 18 Nov 2025 09:39:22 +0800 [thread overview]
Message-ID: <aRvOSnaUt1E+/pkC@intel.com> (raw)
In-Reply-To: <CABgObfaF4YO0Zd5PKJ3u7kRB0engmsSywnzztV8BKm5yUyQdmQ@mail.gmail.com>
On Tue, Nov 18, 2025 at 12:29:19AM +0100, Paolo Bonzini wrote:
>Il mer 12 nov 2025, 02:54 Chao Gao <chao.gao@intel.com> ha scritto:
>>
>> Shouldn't we check guest's capabilities rather than host's,
>>
>> i.e., guest_cpu_cap_has(X86_FEATURE_APX)?
>
>As the manual says, you're free to use the extended field if
>available, and it's faster.
The point is, from the guest's perspective, the field is available iff the vCPU
supports APX. KVM (L0) doesn't need to virtualize VMCS12's EII field if the vCPU
doesn't have APX.
For other call sites of vmx_egpr_enabled(), I agree we should just check host
capabilities.
next prev parent reply other threads:[~2025-11-18 1:39 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-10 18:01 [PATCH RFC v1 00/20] KVM: x86: Support APX feature for guests Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 01/20] KVM: x86: Rename register accessors to be GPR-specific Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 02/20] KVM: x86: Refactor GPR accessors to differentiate register access types Chang S. Bae
2025-11-11 18:08 ` Paolo Bonzini
2025-11-13 23:19 ` Chang S. Bae
2025-11-11 18:11 ` Paolo Bonzini
2025-11-13 23:18 ` Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 03/20] KVM: x86: Implement accessors for extended GPRs Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 04/20] KVM: VMX: Introduce unified instruction info structure Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 05/20] KVM: VMX: Refactor instruction information retrieval Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 06/20] KVM: VMX: Refactor GPR index retrieval from exit qualification Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 07/20] KVM: nVMX: Support the extended instruction info field Chang S. Bae
2025-11-11 17:48 ` Paolo Bonzini
2025-11-12 1:54 ` Chao Gao
2025-11-13 23:21 ` Chang S. Bae
2025-11-17 23:29 ` Paolo Bonzini
2025-11-18 1:39 ` Chao Gao [this message]
2025-11-18 10:33 ` Paolo Bonzini
2025-11-13 23:20 ` Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 08/20] KVM: VMX: Support extended register index in exit handling Chang S. Bae
2025-11-11 17:45 ` Paolo Bonzini
2025-11-13 23:22 ` Chang S. Bae
2025-11-13 23:40 ` Paolo Bonzini
2025-11-10 18:01 ` [PATCH RFC v1 09/20] KVM: x86: Support EGPR accessing and tracking for instruction emulation Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 10/20] KVM: x86: Refactor REX prefix handling in " Chang S. Bae
2025-11-11 18:17 ` Paolo Bonzini
2025-11-13 23:23 ` Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 11/20] KVM: x86: Refactor opcode table lookup " Chang S. Bae
2025-11-11 16:55 ` Paolo Bonzini
2025-11-13 23:24 ` Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 12/20] KVM: x86: Support REX2-extended register index in the decoder Chang S. Bae
2025-11-11 16:53 ` Paolo Bonzini
2025-11-13 23:26 ` Chang S. Bae
2025-11-11 16:53 ` Paolo Bonzini
2025-11-10 18:01 ` [PATCH RFC v1 13/20] KVM: x86: Add REX2 opcode tables to the instruction decoder Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 14/20] KVM: x86: Emulate REX2-prefixed 64-bit absolute jump Chang S. Bae
2025-11-11 16:39 ` Paolo Bonzini
2025-11-13 23:27 ` Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 15/20] KVM: x86: Reject EVEX-prefix instructions in the emulator Chang S. Bae
2025-11-11 16:37 ` Paolo Bonzini
2025-11-13 23:28 ` Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 16/20] KVM: x86: Decode REX2 prefix " Chang S. Bae
2025-11-11 17:55 ` Paolo Bonzini
2025-11-13 23:30 ` Chang S. Bae
2025-11-13 23:34 ` Paolo Bonzini
2025-11-17 20:01 ` Chang S. Bae
2025-11-17 23:33 ` Paolo Bonzini
2025-11-10 18:01 ` [PATCH RFC v1 17/20] KVM: x86: Prepare APX state setting in XCR0 Chang S. Bae
2025-11-11 16:59 ` Paolo Bonzini
2025-11-13 23:32 ` Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 18/20] KVM: x86: Expose APX foundational feature bit to guests Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 19/20] KVM: x86: Expose APX sub-features " Chang S. Bae
2025-11-10 18:01 ` [PATCH RFC v1 20/20] KVM: selftests: Add APX state handling and XCR0 sanity checks Chang S. Bae
2025-11-10 18:50 ` [PATCH RFC v1 00/20] KVM: x86: Support APX feature for guests Chang S. Bae
2025-11-11 18:14 ` Paolo Bonzini
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