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Tsirkin" To: Parav Pandit Cc: "virtualization@lists.linux.dev" , "jasowang@redhat.com" , "stefanha@redhat.com" , "pbonzini@redhat.com" , "xuanzhuo@linux.alibaba.com" , "stable@vger.kernel.org" , Max Gurtovoy , "NBU-Contact-Li Rongqing (EXTERNAL)" Subject: Re: [PATCH] Revert "virtio_pci: Support surprise removal of virtio pci device" Message-ID: <20250822090249-mutt-send-email-mst@kernel.org> References: <20250822091706.21170-1-parav@nvidia.com> <20250822060839-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Aug 22, 2025 at 12:22:50PM +0000, Parav Pandit wrote: > > From: Michael S. Tsirkin > > Sent: 22 August 2025 03:52 PM > > > > On Fri, Aug 22, 2025 at 12:17:06PM +0300, Parav Pandit wrote: > > > This reverts commit 43bb40c5b926 ("virtio_pci: Support surprise removal of > > virtio pci device"). > > > > > > Virtio drivers and PCI devices have never fully supported true > > > surprise (aka hot unplug) removal. Drivers historically continued > > > processing and waiting for pending I/O and even continued synchronous > > > device reset during surprise removal. Devices have also continued > > > completing I/Os, doing DMA and allowing device reset after surprise > > > removal to support such drivers. > > > > > > Supporting it correctly would require a new device capability > > > > If a device is removed, it is removed. > This is how it was implemented and none of the virtio drivers supported it. > So vendors had stepped away from such device implementation. > (not just us). If the slot does not have a mechanical interlock, I can pull the device out. It's not up to a device implementation. -- MST