[PATCH] vdpa/mlx5: Fix mlx5_vdpa_get_config() endianness on big-endian machines.

From: Konstantin Shkolnyy
Date: Thu Jan 30 2025 - 16:44:38 EST


mlx5_vdpa_dev_add() doesn’t initialize mvdev->actual_features. It’s
initialized later by mlx5_vdpa_set_driver_features(). However,
mlx5_vdpa_get_config() depends on the VIRTIO_F_VERSION_1 flag in
actual_features to return data with correct endianness. When it’s called
before mlx5_vdpa_set_driver_features(), the flag is clear, and the data are
returned as big-endian on big-endian machines, while QEMU interprets them
as little-endian.

Signed-off-by: Konstantin Shkolnyy <kshk@xxxxxxxxxxxxx>
---
drivers/vdpa/mlx5/net/mlx5_vnet.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 36099047560d..f9ea240b8145 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -3884,6 +3884,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
ndev->mvdev.max_vqs = max_vqs;
mvdev = &ndev->mvdev;
mvdev->mdev = mdev;
+ mvdev->actual_features = device_features;

ndev->vqs = kcalloc(max_vqs, sizeof(*ndev->vqs), GFP_KERNEL);
ndev->event_cbs = kcalloc(max_vqs + 1, sizeof(*ndev->event_cbs), GFP_KERNEL);
--
2.34.1