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[80.230.79.236]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48448ed38cfsm12369287f8f.19.2026.09.03.04.55.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Sep 2026 04:55:52 -0700 (PDT) Date: Thu, 3 Sep 2026 07:55:49 -0400 From: "Michael S. Tsirkin" To: Karl Mehltretter Cc: Jason Wang , Gerd Hoffmann , Xuan Zhuo , Eugenio =?iso-8859-1?Q?P=E9rez?= , Dmitry Torokhov , Rusty Russell , Pawel Moll , virtualization@lists.linux.dev, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] virtio-mmio: synchronize callbacks during device reset Message-ID: <20260903075143-mutt-send-email-mst@kernel.org> References: <20260818040433.66986-1-kmehltretter@gmail.com> <20260818040433.66986-2-kmehltretter@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@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: <20260818040433.66986-2-kmehltretter@gmail.com> On Tue, Aug 18, 2026 at 06:04:32AM +0200, Karl Mehltretter wrote: > virtio_reset_device() promises that vq callbacks are not in progress > once it returns, but vm_reset() only writes 0 to the status register. > A callback that has already entered vring_interrupt() keeps running > while the driver tears down the state it uses. > > Wait for a status read to return 0, so the device has stopped raising > interrupts, then synchronize_irq() as vp_reset() does with > vp_synchronize_vectors(). > > Fixes: edfd52e63672 ("virtio: Add platform bus driver for memory mapped virtio device") > Assisted-by: Claude:claude-fable-5 > Signed-off-by: Karl Mehltretter I htink we should instead drop vp_synchronize_vectors from vp_reset and instead call virtio_synchronize_cbs from virtio_reset_device. > --- > drivers/virtio/virtio_mmio.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c > index 510b7c4efdff8..a2ca03dbe803d 100644 > --- a/drivers/virtio/virtio_mmio.c > +++ b/drivers/virtio/virtio_mmio.c > @@ -55,6 +55,7 @@ > #define pr_fmt(fmt) "virtio-mmio: " fmt > > #include > +#include > #include > #include > #include > @@ -254,6 +255,11 @@ static void vm_reset(struct virtio_device *vdev) > > /* 0 status means a reset. */ > writel(0, vm_dev->base + VIRTIO_MMIO_STATUS); > + > + /* Wait for reset completion before flushing callbacks. */ > + while (vm_get_status(vdev)) > + fsleep(1000); only needed for v3 and up > + synchronize_irq(platform_get_irq(vm_dev->pdev, 0)); > } > > > -- > 2.53.0