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AJvYcCVBseh735lN8RXh4a22RS+jDe8mRT4rw+2h8tCh0uBAAj2Iea2WORJnk3b1bhfwHRo/aQg1ZXXS4VeWVq8+gXR6TBMqMreGK8Y19c17 X-Gm-Message-State: AOJu0Yy8qyaRMbrzybrppkmY3SV+WjL1n806kDVBGxhkvX75W4Cg75iN iQ4E7zoVz+o/fUuM65YWbBT8hgAH13S8w+LYreLCcnu4+5BpnN6Z9gRXK5snLr+KCoJaZuGSpyM lew== X-Google-Smtp-Source: AGHT+IGN4vuhhXu6RHaKsQDssSGbwGUwHoIe3QpHFtYc97Yq/BzD4QZntnxHirq8V1PdJAs18Y57hXAU0Tg= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:d4cd:b0:1e4:7bf1:52b with SMTP id o13-20020a170902d4cd00b001e47bf1052bmr697plg.7.1714151339477; Fri, 26 Apr 2024 10:08:59 -0700 (PDT) Date: Fri, 26 Apr 2024 10:08:57 -0700 In-Reply-To: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240425233951.3344485-1-seanjc@google.com> <20240425233951.3344485-3-seanjc@google.com> Message-ID: Subject: Re: [PATCH 2/4] KVM: x86: Register emergency virt callback in common code, via kvm_x86_ops From: Sean Christopherson To: Chao Gao Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" On Fri, Apr 26, 2024, Chao Gao wrote: > >diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h > >index 502704596c83..afddfe3747dd 100644 > >--- a/arch/x86/kvm/vmx/x86_ops.h > >+++ b/arch/x86/kvm/vmx/x86_ops.h > >@@ -15,6 +15,7 @@ void vmx_hardware_unsetup(void); > > int vmx_check_processor_compat(void); > > int vmx_hardware_enable(void); > > void vmx_hardware_disable(void); > >+void vmx_emergency_disable(void); > > int vmx_vm_init(struct kvm *kvm); > > void vmx_vm_destroy(struct kvm *kvm); > > int vmx_vcpu_precreate(struct kvm *kvm); > >diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > >index e9ef1fa4b90b..12e88aa2cca2 100644 > >--- a/arch/x86/kvm/x86.c > >+++ b/arch/x86/kvm/x86.c > >@@ -9797,6 +9797,8 @@ int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops) > > > > kvm_ops_update(ops); > > > >+ cpu_emergency_register_virt_callback(kvm_x86_ops.emergency_disable); > >+ > > vmx_emergency_disable() accesses loaded_vmcss_on_cpu but now it may be called > before loaded_vmcss_on_cpu is initialized. This may be not a problem for now > given the check for X86_CR4_VMXE in vmx_emergency_disable(). But relying on > that check is fragile. I think it is better to apply the patch below from Isaku > before this patch. > > https://lore.kernel.org/kvm/c1b7f0e5c2476f9f565acda5c1e746b8d181499b.1708933498.git.isaku.yamahata@intel.com/ Agreed, good eyeballs, and thanks for the reviews!