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* [PATCH] vdpa/mlx5: set_features should allow reset to zero
@ 2021-02-19 11:54 Si-Wei Liu
  2021-02-21 14:44 ` Eli Cohen
                   ` (2 more replies)
  0 siblings, 3 replies; 64+ messages in thread
From: Si-Wei Liu @ 2021-02-19 11:54 UTC (permalink / raw)
  To: mst, jasowang, elic; +Cc: linux-kernel, virtualization, netdev, si-wei.liu

Commit 452639a64ad8 ("vdpa: make sure set_features is invoked
for legacy") made an exception for legacy guests to reset
features to 0, when config space is accessed before features
are set. We should relieve the verify_min_features() check
and allow features reset to 0 for this case.

It's worth noting that not just legacy guests could access
config space before features are set. For instance, when
feature VIRTIO_NET_F_MTU is advertised some modern driver
will try to access and validate the MTU present in the config
space before virtio features are set. Rejecting reset to 0
prematurely causes correct MTU and link status unable to load
for the very first config space access, rendering issues like
guest showing inaccurate MTU value, or failure to reject
out-of-range MTU.

Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
---
 drivers/vdpa/mlx5/net/mlx5_vnet.c | 15 +--------------
 1 file changed, 1 insertion(+), 14 deletions(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 7c1f789..540dd67 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -1490,14 +1490,6 @@ static u64 mlx5_vdpa_get_features(struct vdpa_device *vdev)
 	return mvdev->mlx_features;
 }
 
-static int verify_min_features(struct mlx5_vdpa_dev *mvdev, u64 features)
-{
-	if (!(features & BIT_ULL(VIRTIO_F_ACCESS_PLATFORM)))
-		return -EOPNOTSUPP;
-
-	return 0;
-}
-
 static int setup_virtqueues(struct mlx5_vdpa_net *ndev)
 {
 	int err;
@@ -1558,18 +1550,13 @@ static int mlx5_vdpa_set_features(struct vdpa_device *vdev, u64 features)
 {
 	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
 	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
-	int err;
 
 	print_features(mvdev, features, true);
 
-	err = verify_min_features(mvdev, features);
-	if (err)
-		return err;
-
 	ndev->mvdev.actual_features = features & ndev->mvdev.mlx_features;
 	ndev->config.mtu = cpu_to_mlx5vdpa16(mvdev, ndev->mtu);
 	ndev->config.status |= cpu_to_mlx5vdpa16(mvdev, VIRTIO_NET_S_LINK_UP);
-	return err;
+	return 0;
 }
 
 static void mlx5_vdpa_set_config_cb(struct vdpa_device *vdev, struct vdpa_callback *cb)
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 64+ messages in thread

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Thread overview: 64+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-19 11:54 [PATCH] vdpa/mlx5: set_features should allow reset to zero Si-Wei Liu
2021-02-21 14:44 ` Eli Cohen
2021-02-21 21:52   ` Michael S. Tsirkin
2021-02-22  6:05     ` Eli Cohen
2021-02-23  9:26       ` Michael S. Tsirkin
2021-02-23  9:48         ` Jason Wang
2021-02-23  9:55           ` Michael S. Tsirkin
2021-02-22  4:14 ` Jason Wang
2021-02-22  7:34   ` Michael S. Tsirkin
2021-02-23  1:12     ` Si-Wei Liu
2021-02-23  2:03       ` Jason Wang
2021-02-23 13:26         ` Michael S. Tsirkin
2021-02-23 19:35           ` Si-Wei Liu
2021-02-24  3:20             ` Jason Wang
2021-02-24  5:17               ` Michael S. Tsirkin
2021-02-24  6:02                 ` Jason Wang
2021-02-24  6:45                 ` Eli Cohen
2021-02-24  6:47                   ` Michael S. Tsirkin
2021-02-24  6:55                     ` Jason Wang
2021-02-24  7:12                       ` Michael S. Tsirkin
2021-02-24 12:40                         ` Eli Cohen
2021-02-24  7:17                       ` Eli Cohen
2021-02-24  5:04             ` Michael S. Tsirkin
2021-02-24  6:04               ` Jason Wang
2021-02-24  6:46                 ` Michael S. Tsirkin
2021-02-24  6:53                   ` Jason Wang
2021-02-24  7:17                     ` Michael S. Tsirkin
     [not found]                       ` <babc654d-8dcd-d8a2-c3b6-d20cc4fc554c@redhat.com>
2021-02-24  8:43                         ` Michael S. Tsirkin
2021-02-24  9:30                           ` Jason Wang
2021-02-28 21:30                             ` Michael S. Tsirkin
2021-03-01  3:53                               ` Jason Wang
2021-02-24 18:24               ` Si-Wei Liu
2021-02-26  0:56                 ` Si-Wei Liu
2021-02-28 21:27                   ` Michael S. Tsirkin
2021-03-01 18:08                     ` Si-Wei Liu
2021-02-28 21:28                 ` Michael S. Tsirkin
2021-02-28 21:34                 ` Michael S. Tsirkin
2021-03-01  3:56                   ` Jason Wang
2021-03-02  9:47                     ` Michael S. Tsirkin
2021-03-02 10:53                       ` Jason Wang
2021-02-22 17:09   ` Si-Wei Liu
2021-02-23  2:03     ` Jason Wang
2021-02-23  9:25     ` Michael S. Tsirkin
2021-02-23  9:46       ` Jason Wang
2021-02-23 10:01         ` Michael S. Tsirkin
2021-02-23 10:17           ` Jason Wang
2021-02-24  9:40             ` Jason Wang
2021-02-23 10:04         ` [virtio-dev] " Cornelia Huck
2021-02-23 10:31           ` Jason Wang
2021-02-23 10:58             ` Cornelia Huck
2021-02-24  9:29               ` Jason Wang
2021-02-24 11:12                 ` Cornelia Huck
2021-02-25  4:36                   ` Jason Wang
2021-02-25 13:26                     ` Cornelia Huck
2021-02-25 18:53                     ` Michael S. Tsirkin
2021-02-26  8:19                       ` Jason Wang
2021-02-28 21:25                         ` Michael S. Tsirkin
2021-03-01  3:51                           ` Jason Wang
2021-03-02 12:08                             ` Cornelia Huck
     [not found]                               ` <5f6972fe-7246-b622-958d-9cab8dd98e21@redhat.com>
2021-03-03  8:29                                 ` Cornelia Huck
2021-03-04  8:24                                   ` Jason Wang
2021-03-04 13:50                                     ` Cornelia Huck
2021-03-05  3:01                                       ` Jason Wang
2021-02-23 12:26 ` Michael S. Tsirkin

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