Re: [PATCH] vdpa/mlx5: Setup driver only if VIRTIO_CONFIG_S_DRIVER_OK

On Mon, Sep 07, 2020 at 02:43:51PM +0300, Eli Cohen wrote:

On Mon, Sep 07, 2020 at 07:34:00AM -0400, Michael S. Tsirkin wrote:

quoted

On Mon, Sep 07, 2020 at 10:51:36AM +0300, Eli Cohen wrote:

quoted

If the memory map changes before the driver status is
VIRTIO_CONFIG_S_DRIVER_OK, don't attempt to create resources because it
may fail. For example, if the VQ is not ready there is no point in
creating resources.

Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
Signed-off-by: Eli Cohen <redacted>

Could you add a bit more data about the problem to the log?
To be more exact, what exactly happens right now?

Sure I can.

set_map() is used by mlx5 vdpa to create a memory region based on the
address map passed by the iotlb argument. If I get successive calls, I
will destroy the current memory region and build another one based on
the new address mapping. I also need to setup the hardware resources
since they depend on the memory region.

If these calls happen before DRIVER_OK, It means it that driver VQs may
also not been setup and I may not create them yet. In this case I want
to avoid setting up the other resources and defer this till I get DRIVER
OK.

Let me know if that answers your question so I can post another patch.

it does, pls do.

quoted

quoted

---
 drivers/vdpa/mlx5/net/mlx5_vnet.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 9df69d5efe8c..c89cd48a0aab 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -1645,6 +1645,9 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_net *ndev, struct vhost_iotlb *
 	if (err)
 		goto err_mr;
 
+	if (!(ndev->mvdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
+		return 0;
+
 	restore_channels_info(ndev);
 	err = setup_driver(ndev);
 	if (err)

-- 
2.26.0

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