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AJvYcCWB6aOilxIqPyyM+qRyOzrfKBXMNp+BLHzAUbpAJK3+AYDwVPVRNPa/OGoXSxwGyUKueCv07ff0WlRTlPs=@vger.kernel.org X-Gm-Message-State: AOJu0Yx5S0OfEdSgXaSYsF5KTpBNgARfc+bRudXTgkX0c/rJjJgQUAgu FWxq0X+5kqquZEa7QYOtqzWua3325gVnieU4jnCmLx7lxAI8pfVzM0PRRKUtRRUqGwY1NdR56UH JjfzdWA== X-Google-Smtp-Source: AGHT+IHuWddlIKYwLsPDO46b/KLE6cD3JB+tatHKJT4EdyfraYehwgzt5OK7QnPmkojgvWHkl0xgI31PLXg= X-Received: from pjbsn5.prod.google.com ([2002:a17:90b:2e85:b0:32b:80cc:6439]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:ab8e:b0:25c:e2c:6653 with SMTP id d9443c01a7336-25d271344a4mr24620975ad.48.1757688170547; Fri, 12 Sep 2025 07:42:50 -0700 (PDT) Date: Fri, 12 Sep 2025 07:42:49 -0700 In-Reply-To: <20250909093953.202028-16-chao.gao@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250909093953.202028-1-chao.gao@intel.com> <20250909093953.202028-16-chao.gao@intel.com> Message-ID: Subject: Re: [PATCH v14 15/22] KVM: x86: Don't emulate instructions guarded by CET From: Sean Christopherson To: Chao Gao Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, acme@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, john.allen@amd.com, mingo@kernel.org, mingo@redhat.com, minipli@grsecurity.net, mlevitsk@redhat.com, namhyung@kernel.org, pbonzini@redhat.com, prsampat@amd.com, rick.p.edgecombe@intel.com, shuah@kernel.org, tglx@linutronix.de, weijiang.yang@intel.com, x86@kernel.org, xin@zytor.com, xiaoyao.li@intel.com Content-Type: text/plain; charset="us-ascii" On Tue, Sep 09, 2025, Chao Gao wrote: > @@ -4068,9 +4070,11 @@ static const struct opcode group4[] = { > static const struct opcode group5[] = { > F(DstMem | SrcNone | Lock, em_inc), > F(DstMem | SrcNone | Lock, em_dec), > - I(SrcMem | NearBranch | IsBranch, em_call_near_abs), > - I(SrcMemFAddr | ImplicitOps | IsBranch, em_call_far), > - I(SrcMem | NearBranch | IsBranch, em_jmp_abs), > + I(SrcMem | NearBranch | IsBranch | ShadowStack | IndirBrnTrk, > + em_call_near_abs), Argh, these wraps are killing me. I spent a good 20 seconds staring at the code trying to figure out which instructions are affected. There's definitely a bit of -ENOCOFFEE going on, but there's also zero reason to wrap. > + I(SrcMemFAddr | ImplicitOps | IsBranch | ShadowStack | IndirBrnTrk, > + em_call_far), > + I(SrcMem | NearBranch | IsBranch | IndirBrnTrk, em_jmp_abs), > I(SrcMemFAddr | ImplicitOps | IsBranch, em_jmp_far), > I(SrcMem | Stack | TwoMemOp, em_push), D(Undefined), > };