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([2001:b07:6468:f312:80b0:f446:bb61:1dbb]) by smtp.gmail.com with ESMTPSA id a10sm4364863wmd.3.2020.07.28.05.09.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 28 Jul 2020 05:09:19 -0700 (PDT) Subject: Re: migration: broken snapshot saves appear on s390 when small fields in migration stream removed To: Max Reitz , Vladimir Sementsov-Ogievskiy , Bruce Rogers , Claudio Fontana , Thomas Huth , Juan Quintela , "Dr. David Alan Gilbert" , Kevin Wolf References: <8bbafdec-836d-b7de-cab8-7a325b6e238d@suse.de> <55c406cd-b9ca-4e9b-0acd-d33cfe2a70e3@redhat.com> <8125b1ff-373a-aadc-eccf-27c567007a27@redhat.com> <8ff7eeab-bef1-0957-a95c-72819680c431@suse.de> <1db6d502-73d1-5e3d-10d1-796d80ab8f07@suse.de> <13728e69-75a5-2edc-9ed3-6e08d94c722d@suse.de> <636bb3c4-2242-284b-30cd-299f447117c2@suse.de> <5f455e82e0a4f3662918dcdc85d1cfc5a3187896.camel@suse.com> <72ff33d4-653f-5702-fc04-9090653ab782@redhat.com> <0e175bbb-6d5e-f509-7a4f-e3e4769c13a1@redhat.com> From: Paolo Bonzini Message-ID: <1c3c876b-6f33-62e9-ace3-7f83e62ceea2@redhat.com> Date: Tue, 28 Jul 2020 14:09:18 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <0e175bbb-6d5e-f509-7a4f-e3e4769c13a1@redhat.com> Content-Language: en-US X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=207.211.31.81; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/28 00:06:48 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, 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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Jason J. Herne" , Fam Zheng , Liang Yan , Peter Maydell , Cornelia Huck , qemu-devel , Stefan Hajnoczi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 28/07/20 13:45, Max Reitz wrote: >> Is it possible to make a quick testcase using qemu-io? > This seems to work: > > $ qemu-img create -f qcow2 -o cluster_size=512 base.qcow2 512 > $ qemu-img create -f qcow2 -o cluster_size=512 -F qcow2 -b base.qcow2 \ > top.qcow2 1024 > $ qemu-io -c 'write -P 42 0 512' top.qcow2 > $ qemu-io -c 'read -v 0 1024' top.qcow2 > > That should print 512 times “2a” and then 512 times “00”, but beyond > 512, the buffer stays uninitialized; instead, the first 512 bytes are > zeroed. (With the patch, it works as expected.) > Wow, that's great (and a good recipe for qemu-iotests too). Thanks. Paolo