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 and
driver negotiation in the virtio specification to safely stop
I/O and free queue memory. Failure to do so either breaks all the
existing drivers with call trace listed in the commit or crashes the
host on continuing the DMA. Hence, until such specification and devices
are invented, restore the previous behavior of treating surprise
removal as graceful removal to avoid regressions and maintain system
stability same as before the
commit 43bb40c5b926 ("virtio_pci: Support surprise removal of virtio pci
device").
As explained above, previous analysis of solving this only in driver
was incomplete and non-reliable at [1] and at [2]; Hence reverting commit
43bb40c5b926 ("virtio_pci: Support surprise removal of virtio pci device")
is still the best stand to restore failures of virtio net and
block devices.
[1]
https://lore.kernel.org/virtualization/cy8pr12mb719506cc5613eb100bc6c638dc...@cy8pr12mb7195.namprd12.prod.outlook.com/#t
[2]
https://lore.kernel.org/virtualization/20250602024358.57114-1-pa...@nvidia.com/
Fixes: 43bb40c5b926 ("virtio_pci: Support surprise removal of virtio pci
device")
Cc: sta...@vger.kernel.org
Reported-by: lirongq...@baidu.com
Closes:
https://lore.kernel.org/virtualization/c45dd68698cd47238c55fb73ca9b4...@baidu.com/
Signed-off-by: Parav Pandit <pa...@nvidia.com>
---
drivers/virtio/virtio_pci_common.c | 7 -------
1 file changed, 7 deletions(-)
diff --git a/drivers/virtio/virtio_pci_common.c
b/drivers/virtio/virtio_pci_common.c
index d6d79af44569..dba5eb2eaff9 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -747,13 +747,6 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
struct device *dev = get_device(&vp_dev->vdev.dev);
- /*
- * Device is marked broken on surprise removal so that virtio upper
- * layers can abort any ongoing operation.
- */
- if (!pci_device_is_present(pci_dev))
- virtio_break_device(&vp_dev->vdev);
-
pci_disable_sriov(pci_dev);
unregister_virtio_device(&vp_dev->vdev);
--
2.26.2
