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[70.30.145.63]) by smtp.gmail.com with ESMTPSA id t22-20020a05620a0b1600b0073917fae4f8sm11740850qkg.25.2023.02.21.15.58.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Feb 2023 15:58:16 -0800 (PST) Date: Tue, 21 Feb 2023 18:58:15 -0500 From: Peter Xu To: Gavin Shan Cc: qemu-arm@nongnu.org, qemu-devel@nongnu.org, pbonzini@redhat.com, peter.maydell@linaro.org, david@redhat.com, philmd@linaro.org, mst@redhat.com, cohuck@redhat.com, quintela@redhat.com, dgilbert@redhat.com, maz@kernel.org, zhenyzha@redhat.com, shan.gavin@gmail.com Subject: Re: [PATCH v1 3/6] kvm: Synchronize the backup bitmap in the last stage Message-ID: References: <20230213003925.40158-1-gshan@redhat.com> <20230213003925.40158-4-gshan@redhat.com> <08c954d7-f4e4-4d63-28fc-50128f4bc2d7@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <08c954d7-f4e4-4d63-28fc-50128f4bc2d7@redhat.com> Received-SPF: pass client-ip=170.10.129.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Hi, Gavin, On Wed, Feb 22, 2023 at 10:44:07AM +1100, Gavin Shan wrote: > Peter, could you please give some hints for me to understand the atomic > and non-atomic update here? Ok, I will drop this part of changes in next > revision with the assumption that we have atomic update supported for > ARM64. See commit f39b7d2b96. Please don't remove the change in this patch. The comment was just something I thought about when reading, not something I suggested to change. If to remove it we'll need to remove the whole chunk not your changes alone here. Still, please take it with a grain of salt before anyone can help to confirm because I can miss something else here. In short: before we know anything solidly, your current code is exactly correct, AFAICT. Thanks, -- Peter Xu