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Tsirkin" , Jason Wang , =?UTF-8?q?Eugenio=20P=C3=A9rez?= Cc: Xuan Zhuo , virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, Yuho Choi , stable@vger.kernel.org Subject: [PATCH v1] vdpa/vp_vdpa: Wait for device reset to complete Date: Sat, 26 Sep 2026 17:14:52 -0400 Message-ID: <20260926211507.1330179-1-oss.patchbox@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit vp_vdpa_reset() writes 0 to device_status and returns success right away. The virtio specification requires the driver to wait until a read of device_status returns 0 before reinitializing the device, and virtio_pci_modern's vp_reset() does exactly that: the read-back flushes the posted status write and any in-flight device writes, including MSI-X messages. Without it, vhost-vdpa (or virtio-vdpa) can go on to tear down the IOTLB/IOMMU mappings or reprogram the queues while the device has not yet finished its reset, and may still be DMAing to the old virtqueue addresses. The MSI-X vectors are also freed while an interrupt from the old configuration may still be in flight. Poll device_status after writing 0, in the same way as vp_reset(), before freeing the IRQs and returning. Fixes: 64b9f64f80a6 ("vdpa: introduce virtio pci driver") Cc: stable@vger.kernel.org Signed-off-by: Yuho Choi --- Compile-tested only (x86_64 defconfig + VP_VDPA, W=1). drivers/vdpa/virtio_pci/vp_vdpa.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c index f2eb654b1665..4285cb968479 100644 --- a/drivers/vdpa/virtio_pci/vp_vdpa.c +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c @@ -8,6 +8,7 @@ * Based on virtio_pci_modern.c. */ +#include #include #include #include @@ -236,6 +237,9 @@ static int vp_vdpa_reset(struct vdpa_device *vdpa) u8 s = vp_vdpa_get_status(vdpa); vp_modern_set_status(mdev, 0); + /* Wait for the reset to complete */ + while (vp_modern_get_status(mdev)) + fsleep(1000); if (s & VIRTIO_CONFIG_S_DRIVER_OK) vp_vdpa_free_irq(vp_vdpa); base-commit: aa98230e410f0ed212b6788c46b1e4d49e0ff7ca -- 2.43.0