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 <[email protected]>
Acked-by: Jason Wang <[email protected]>
---
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 7c1f789..ce6aae8 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -1777,7 +1777,6 @@ 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;
@@ -1786,6 +1785,7 @@ 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
On Wed, Feb 10, 2021 at 01:48:00PM -0800, 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 <[email protected]>
> Acked-by: Jason Wang <[email protected]>
Acked-by: Eli Cohen <[email protected]>
> ---
> 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 7c1f789..ce6aae8 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1777,7 +1777,6 @@ 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;
> @@ -1786,6 +1785,7 @@ 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
>
On Thu, Feb 11, 2021 at 09:33:14AM +0200, Eli Cohen wrote:
> On Wed, Feb 10, 2021 at 01:48:00PM -0800, 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 <[email protected]>
> > Acked-by: Jason Wang <[email protected]>
>
> Acked-by: Eli Cohen <[email protected]>
>
I take it back. I think we don't need to clear the indexes at all. In
case we need to restore indexes we'll get the right values through
set_vq_state(). If we suspend the virtqueue due to VM being suspended,
qemu will query first and will provide the the queried value. In case of
VM reboot, it will provide 0 in set_vq_state().
I am sending a patch that addresses both reboot and suspend.
> > ---
> > 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 7c1f789..ce6aae8 100644
> > --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> > @@ -1777,7 +1777,6 @@ 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;
> > @@ -1786,6 +1785,7 @@ 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
> >
On 2/16/2021 7:21 AM, Eli Cohen wrote:
> On Thu, Feb 11, 2021 at 09:33:14AM +0200, Eli Cohen wrote:
>> On Wed, Feb 10, 2021 at 01:48:00PM -0800, 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 <[email protected]>
>>> Acked-by: Jason Wang <[email protected]>
>> Acked-by: Eli Cohen <[email protected]>
>>
> I take it back. I think we don't need to clear the indexes at all. In
> case we need to restore indexes we'll get the right values through
> set_vq_state(). If we suspend the virtqueue due to VM being suspended,
> qemu will query first and will provide the the queried value. In case of
> VM reboot, it will provide 0 in set_vq_state().
>
> I am sending a patch that addresses both reboot and suspend.
With set_vq_state() repurposed to restoring used_index I'm fine with
this approach.
Do I have to repost a v3 of this series while dropping the 3rd patch?
-Siwei
>
>>> ---
>>> 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 7c1f789..ce6aae8 100644
>>> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
>>> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>>> @@ -1777,7 +1777,6 @@ 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;
>>> @@ -1786,6 +1785,7 @@ 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
>>>
On 2021/2/18 上午5:55, Si-Wei Liu wrote:
>
>
> On 2/16/2021 7:21 AM, Eli Cohen wrote:
>> On Thu, Feb 11, 2021 at 09:33:14AM +0200, Eli Cohen wrote:
>>> On Wed, Feb 10, 2021 at 01:48:00PM -0800, 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 <[email protected]>
>>>> Acked-by: Jason Wang <[email protected]>
>>> Acked-by: Eli Cohen <[email protected]>
>>>
>> I take it back. I think we don't need to clear the indexes at all. In
>> case we need to restore indexes we'll get the right values through
>> set_vq_state(). If we suspend the virtqueue due to VM being suspended,
>> qemu will query first and will provide the the queried value. In case of
>> VM reboot, it will provide 0 in set_vq_state().
>>
>> I am sending a patch that addresses both reboot and suspend.
> With set_vq_state() repurposed to restoring used_index I'm fine with
> this approach.
>
> Do I have to repost a v3 of this series while dropping the 3rd patch?
>
> -Siwei
Yes, please.
Thanks