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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id w25sm2722302edi.22.2021.09.22.23.37.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 22 Sep 2021 23:37:24 -0700 (PDT) Subject: Re: [PATCH] KVM: VMX: Check if bus lock vmexit was preempted To: Hao Xiang , Xiaoyao Li , kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, chenyi.qiang@intel.com, shannon.zhao@linux.alibaba.com, Sean Christopherson References: <1631964600-73707-1-git-send-email-hao.xiang@linux.alibaba.com> <87b411c3-da75-e074-91a4-a73891f9f5f8@redhat.com> <57597778-836c-7bac-7f1d-bcdae0cd6ac4@intel.com> <84cd2713-3cc4-3120-946e-0cf8b8a8187d@linux.alibaba.com> From: Paolo Bonzini Message-ID: <0b8714ed-c3ae-01ee-d2fd-fe7542d01596@redhat.com> Date: Thu, 23 Sep 2021 08:37:21 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <84cd2713-3cc4-3120-946e-0cf8b8a8187d@linux.alibaba.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23/09/21 02:59, Hao Xiang wrote: > EXIT_REASON.bus_lock_detected may or may not be set when > exit_reason=EXIT_REASON_BUS_LOCK,  It clould depend on hardware > implementaion. No matter when intel states it clearly, I think it is > better that we avoid repeated assignment by adding additional check > condition in vmx_handle_exit.  Of course , it is also ok that > hand_bus_lock_vmexit do nothing , but the code is not clear, and the > code logic will be inconsistent with spec description. For 5.16 we'll go with something like Sean's sketch, that sets the bus_lock_detected bit on EXIT_REASON_BUS_LOCK. Paolo