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[176.184.5.132]) by smtp.gmail.com with ESMTPSA id l32-20020a05600c1d2000b003f0321c22basm19001040wms.12.2023.04.03.13.47.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 03 Apr 2023 13:47:14 -0700 (PDT) Message-ID: <2bbe988c-0802-55c3-b2a3-05e3f94e2f04@linaro.org> Date: Mon, 3 Apr 2023 22:47:11 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [PATCH 01/13] virtio-scsi: avoid race between unplug and transport event Content-Language: en-US To: Stefan Hajnoczi , qemu-devel@nongnu.org Cc: Paolo Bonzini , Julia Suvorova , Kevin Wolf , Peter Lieven , Coiby Xu , xen-devel@lists.xenproject.org, Richard Henderson , Stefano Garzarella , qemu-block@nongnu.org, Eduardo Habkost , Paul Durrant , "Richard W.M. Jones" , "Dr. David Alan Gilbert" , Marcel Apfelbaum , Aarushi Mehta , Stefano Stabellini , Fam Zheng , David Woodhouse , Stefan Weil , Juan Quintela , Xie Yongji , Hanna Reitz , Ronnie Sahlberg , eesposit@redhat.com, "Michael S. Tsirkin" , =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , Anthony Perard References: <20230403183004.347205-1-stefanha@redhat.com> <20230403183004.347205-2-stefanha@redhat.com> From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= In-Reply-To: <20230403183004.347205-2-stefanha@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2a00:1450:4864:20::330; envelope-from=philmd@linaro.org; helo=mail-wm1-x330.google.com X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-1.349, RCVD_IN_DNSWL_NONE=-0.0001, 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: 2.1.29 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 On 3/4/23 20:29, Stefan Hajnoczi wrote: > Only report a transport reset event to the guest after the SCSIDevice > has been unrealized by qdev_simple_device_unplug_cb(). > > qdev_simple_device_unplug_cb() sets the SCSIDevice's qdev.realized field > to false so that scsi_device_find/get() no longer see it. > > scsi_target_emulate_report_luns() also needs to be updated to filter out > SCSIDevices that are unrealized. > > These changes ensure that the guest driver does not see the SCSIDevice > that's being unplugged if it responds very quickly to the transport > reset event. > > Signed-off-by: Stefan Hajnoczi > --- > hw/scsi/scsi-bus.c | 3 ++- > hw/scsi/virtio-scsi.c | 18 +++++++++--------- > 2 files changed, 11 insertions(+), 10 deletions(-) > > diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c > index c97176110c..f9bd064833 100644 > --- a/hw/scsi/scsi-bus.c > +++ b/hw/scsi/scsi-bus.c > @@ -487,7 +487,8 @@ static bool scsi_target_emulate_report_luns(SCSITargetReq *r) > DeviceState *qdev = kid->child; > SCSIDevice *dev = SCSI_DEVICE(qdev); > > - if (dev->channel == channel && dev->id == id && dev->lun != 0) { > + if (dev->channel == channel && dev->id == id && dev->lun != 0 && > + qatomic_load_acquire(&dev->qdev.realized)) { Would this be more useful as a qdev_is_realized() helper?