Si-Wei Liu
2021-Feb-06 12:29 UTC
[PATCH 3/3] mlx5_vdpa: defer clear_virtqueues to until DRIVER_OK
While virtq is stopped, get_vq_state() is supposed to
be called to get sync'ed with the latest internal
avail_index from device. The saved avail_index is used
to restate the virtq once device is started. Commit
b35ccebe3ef7 introduced the clear_virtqueues() routine
to reset the saved avail_index, however, the index
gets cleared a bit earlier before get_vq_state() tries
to read it. This would cause consistency problems when
virtq is restarted, e.g. through a series of link down
and link up events. We could defer the clearing of
avail_index to until the device is to be started,
i.e. until VIRTIO_CONFIG_S_DRIVER_OK is set again in
set_status().
Fixes: b35ccebe3ef7 ("vdpa/mlx5: Restore the hardware used index after
change map")
Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com>
---
drivers/vdpa/mlx5/net/mlx5_vnet.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index aa6f8cd..444ab58 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -1785,7 +1785,6 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev,
u8 status)
if (!status) {
mlx5_vdpa_info(mvdev, "performing device reset\n");
teardown_driver(ndev);
- clear_virtqueues(ndev);
mlx5_vdpa_destroy_mr(&ndev->mvdev);
ndev->mvdev.status = 0;
++mvdev->generation;
@@ -1794,6 +1793,7 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev,
u8 status)
if ((status ^ ndev->mvdev.status) & VIRTIO_CONFIG_S_DRIVER_OK) {
if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
+ clear_virtqueues(ndev);
err = setup_driver(ndev);
if (err) {
mlx5_vdpa_warn(mvdev, "failed to setup driver\n");
--
1.8.3.1
Jason Wang
2021-Feb-08 04:38 UTC
[PATCH 3/3] mlx5_vdpa: defer clear_virtqueues to until DRIVER_OK
On 2021/2/6 ??8:29, Si-Wei Liu wrote:> While virtq is stopped, get_vq_state() is supposed to > be called to get sync'ed with the latest internal > avail_index from device. The saved avail_index is used > to restate the virtq once device is started. Commit > b35ccebe3ef7 introduced the clear_virtqueues() routine > to reset the saved avail_index, however, the index > gets cleared a bit earlier before get_vq_state() tries > to read it. This would cause consistency problems when > virtq is restarted, e.g. through a series of link down > and link up events. We could defer the clearing of > avail_index to until the device is to be started, > i.e. until VIRTIO_CONFIG_S_DRIVER_OK is set again in > set_status(). > > Fixes: b35ccebe3ef7 ("vdpa/mlx5: Restore the hardware used index after change map") > Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com>Acked-by: Jason Wang <jasowang at redhat.com>> --- > drivers/vdpa/mlx5/net/mlx5_vnet.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c > index aa6f8cd..444ab58 100644 > --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c > +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c > @@ -1785,7 +1785,6 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status) > if (!status) { > mlx5_vdpa_info(mvdev, "performing device reset\n"); > teardown_driver(ndev); > - clear_virtqueues(ndev); > mlx5_vdpa_destroy_mr(&ndev->mvdev); > ndev->mvdev.status = 0; > ++mvdev->generation; > @@ -1794,6 +1793,7 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status) > > if ((status ^ ndev->mvdev.status) & VIRTIO_CONFIG_S_DRIVER_OK) { > if (status & VIRTIO_CONFIG_S_DRIVER_OK) { > + clear_virtqueues(ndev); > err = setup_driver(ndev); > if (err) { > mlx5_vdpa_warn(mvdev, "failed to setup driver\n");
Jason Wang
2021-Feb-09 03:37 UTC
[PATCH 3/3] mlx5_vdpa: defer clear_virtqueues to until DRIVER_OK
On 2021/2/6 ??8:29, Si-Wei Liu wrote:> While virtq is stopped, get_vq_state() is supposed to > be called to get sync'ed with the latest internal > avail_index from device. The saved avail_index is used > to restate the virtq once device is started. Commit > b35ccebe3ef7 introduced the clear_virtqueues() routine > to reset the saved avail_index, however, the index > gets cleared a bit earlier before get_vq_state() tries > to read it. This would cause consistency problems when > virtq is restarted, e.g. through a series of link down > and link up events. We could defer the clearing of > avail_index to until the device is to be started, > i.e. until VIRTIO_CONFIG_S_DRIVER_OK is set again in > set_status(). > > Fixes: b35ccebe3ef7 ("vdpa/mlx5: Restore the hardware used index after change map") > Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com> > --- > drivers/vdpa/mlx5/net/mlx5_vnet.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c > index aa6f8cd..444ab58 100644 > --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c > +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c > @@ -1785,7 +1785,6 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status) > if (!status) { > mlx5_vdpa_info(mvdev, "performing device reset\n"); > teardown_driver(ndev); > - clear_virtqueues(ndev); > mlx5_vdpa_destroy_mr(&ndev->mvdev); > ndev->mvdev.status = 0; > ++mvdev->generation; > @@ -1794,6 +1793,7 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status) > > if ((status ^ ndev->mvdev.status) & VIRTIO_CONFIG_S_DRIVER_OK) { > if (status & VIRTIO_CONFIG_S_DRIVER_OK) { > + clear_virtqueues(ndev);Rethink about this. As mentioned in another thread, this in fact breaks set_vq_state().? (See vhost_virtqueue_start() -> vhost_vdpa_set_vring_base() in qemu codes). The issue is that the avail idx is forgot, we need keep it. Thanks> err = setup_driver(ndev); > if (err) { > mlx5_vdpa_warn(mvdev, "failed to setup driver\n");