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[91.219.240.17]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4324ea1b1b1sm83175299f8f.3.2026.01.02.01.59.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Jan 2026 01:59:01 -0800 (PST) From: Vitaly Kuznetsov To: Sean Christopherson , Paolo Bonzini , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li Cc: kvm@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, Jim Mattson , Yosry Ahmed Subject: Re: [PATCH v2 8/8] KVM: SVM: Assert that Hyper-V's HV_SVM_EXITCODE_ENL == SVM_EXIT_SW In-Reply-To: <20251230211347.4099600-9-seanjc@google.com> References: <20251230211347.4099600-1-seanjc@google.com> <20251230211347.4099600-9-seanjc@google.com> Date: Fri, 02 Jan 2026 10:58:59 +0100 Message-ID: <87eco8bajg.fsf@redhat.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Sean Christopherson writes: > Add a build-time assertiont that Hyper-V's "enlightened" exit code is that, > same as the AMD-defined "Reserved for Host" exit code, mostly to help > readers connect the dots and understand why synthesizing a software-defined > exit code is safe/ok. > > Signed-off-by: Sean Christopherson > --- > arch/x86/kvm/svm/hyperv.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/arch/x86/kvm/svm/hyperv.c b/arch/x86/kvm/svm/hyperv.c > index 3ec580d687f5..4f24dcb45116 100644 > --- a/arch/x86/kvm/svm/hyperv.c > +++ b/arch/x86/kvm/svm/hyperv.c > @@ -10,6 +10,12 @@ void svm_hv_inject_synthetic_vmexit_post_tlb_flush(struct kvm_vcpu *vcpu) > { > struct vcpu_svm *svm = to_svm(vcpu); > > + /* > + * The exit code used by Hyper-V for software-defined exits is reserved > + * by AMD specifically for such use cases. > + */ > + BUILD_BUG_ON(HV_SVM_EXITCODE_ENL != SVM_EXIT_SW); > + > svm->vmcb->control.exit_code = HV_SVM_EXITCODE_ENL; > svm->vmcb->control.exit_info_1 = HV_SVM_ENL_EXITCODE_TRAP_AFTER_FLUSH; > svm->vmcb->control.exit_info_2 = 0; Reviewed-by: Vitaly Kuznetsov Alternatively (or additionally?) to BUG_ON, I guess we could've #define HV_SVM_EXITCODE_ENL SVM_EXIT_SW unless including SVM's headers into include/hyperv/hvgdk.h is too big of a mess. -- Vitaly