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[PATCH] virtio-net: correctly report maximum tx_queue_size value

Laurent Vivier posted 1 patch 11 months ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20230605142125.3881859-1-lvivier@redhat.com
Maintainers: "Michael S. Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com>
hw/net/virtio-net.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
[PATCH] virtio-net: correctly report maximum tx_queue_size value
Posted by Laurent Vivier 11 months ago 
Maximum value for tx_queue_size depends on the backend type.
1024 for vDPA/vhost-user, 256 for all the others.

The value is returned by virtio_net_max_tx_queue_size() to set the
parameter:

    n->net_conf.tx_queue_size = MIN(virtio_net_max_tx_queue_size(n),
                                    n->net_conf.tx_queue_size);

But the parameter checking uses VIRTQUEUE_MAX_SIZE (1024).

So the parameter is silently ignored and ethtool reports a different
value than the one provided by the user.

   ... -netdev tap,... -device virtio-net,tx_queue_size=1024

    # ethtool -g enp0s2
    Ring parameters for enp0s2:
    Pre-set maximums:
    RX:		256
    RX Mini:	n/a
    RX Jumbo:	n/a
    TX:		256
    Current hardware settings:
    RX:		256
    RX Mini:	n/a
    RX Jumbo:	n/a
    TX:		256

   ... -netdev vhost-user,... -device virtio-net,tx_queue_size=2048

    Invalid tx_queue_size (= 2048), must be a power of 2 between 256 and 1024

With this patch the correct maximum value is checked and displayed.

For vDPA/vhost-user:

    Invalid tx_queue_size (= 2048), must be a power of 2 between 256 and 1024

For all the others:

    Invalid tx_queue_size (= 512), must be a power of 2 between 256 and 256

Fixes: 2eef278b9e63 ("virtio-net: fix tx queue size for !vhost-user")
Cc: mst@redhat.com
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 hw/net/virtio-net.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 6df6b7329d25..e9905aac83ad 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -3630,12 +3630,12 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
     }
 
     if (n->net_conf.tx_queue_size < VIRTIO_NET_TX_QUEUE_MIN_SIZE ||
-        n->net_conf.tx_queue_size > VIRTQUEUE_MAX_SIZE ||
+        n->net_conf.tx_queue_size > virtio_net_max_tx_queue_size(n) ||
         !is_power_of_2(n->net_conf.tx_queue_size)) {
         error_setg(errp, "Invalid tx_queue_size (= %" PRIu16 "), "
                    "must be a power of 2 between %d and %d",
                    n->net_conf.tx_queue_size, VIRTIO_NET_TX_QUEUE_MIN_SIZE,
-                   VIRTQUEUE_MAX_SIZE);
+                   virtio_net_max_tx_queue_size(n));
         virtio_cleanup(vdev);
         return;
     }
-- 
2.39.2
Re: [PATCH] virtio-net: correctly report maximum tx_queue_size value
Posted by Michael Tokarev 11 months ago 
05.06.2023 17:21, Laurent Vivier wrote:
> Maximum value for tx_queue_size depends on the backend type.
> 1024 for vDPA/vhost-user, 256 for all the others.
> 
> The value is returned by virtio_net_max_tx_queue_size() to set the
> parameter:
> 
>      n->net_conf.tx_queue_size = MIN(virtio_net_max_tx_queue_size(n),
>                                      n->net_conf.tx_queue_size);
> 
> But the parameter checking uses VIRTQUEUE_MAX_SIZE (1024).
> 
> So the parameter is silently ignored and ethtool reports a different
> value than the one provided by the user.
> 
>     ... -netdev tap,... -device virtio-net,tx_queue_size=1024
> 
>      # ethtool -g enp0s2
>      Ring parameters for enp0s2:
>      Pre-set maximums:
>      RX:		256
>      RX Mini:	n/a
>      RX Jumbo:	n/a
>      TX:		256
>      Current hardware settings:
>      RX:		256
>      RX Mini:	n/a
>      RX Jumbo:	n/a
>      TX:		256
> 
>     ... -netdev vhost-user,... -device virtio-net,tx_queue_size=2048
> 
>      Invalid tx_queue_size (= 2048), must be a power of 2 between 256 and 1024
> 
> With this patch the correct maximum value is checked and displayed.
> 
> For vDPA/vhost-user:
> 
>      Invalid tx_queue_size (= 2048), must be a power of 2 between 256 and 1024
> 
> For all the others:
> 
>      Invalid tx_queue_size (= 512), must be a power of 2 between 256 and 256
> 
> Fixes: 2eef278b9e63 ("virtio-net: fix tx queue size for !vhost-user")
> Cc: mst@redhat.com
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> ---
>   hw/net/virtio-net.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)

Is it a -stable material, or not worth fixing in -stable?
To me it looks like it should be fixed.

Thanks,

/mjt
Re: [PATCH] virtio-net: correctly report maximum tx_queue_size value
Posted by Michael S. Tsirkin 11 months ago 
On Mon, Jun 05, 2023 at 04:21:25PM +0200, Laurent Vivier wrote:
> Maximum value for tx_queue_size depends on the backend type.
> 1024 for vDPA/vhost-user, 256 for all the others.
> 
> The value is returned by virtio_net_max_tx_queue_size() to set the
> parameter:
> 
>     n->net_conf.tx_queue_size = MIN(virtio_net_max_tx_queue_size(n),
>                                     n->net_conf.tx_queue_size);
> 
> But the parameter checking uses VIRTQUEUE_MAX_SIZE (1024).
> 
> So the parameter is silently ignored and ethtool reports a different
> value than the one provided by the user.
> 
>    ... -netdev tap,... -device virtio-net,tx_queue_size=1024
> 
>     # ethtool -g enp0s2
>     Ring parameters for enp0s2:
>     Pre-set maximums:
>     RX:		256
>     RX Mini:	n/a
>     RX Jumbo:	n/a
>     TX:		256
>     Current hardware settings:
>     RX:		256
>     RX Mini:	n/a
>     RX Jumbo:	n/a
>     TX:		256
> 
>    ... -netdev vhost-user,... -device virtio-net,tx_queue_size=2048
> 
>     Invalid tx_queue_size (= 2048), must be a power of 2 between 256 and 1024
> 
> With this patch the correct maximum value is checked and displayed.
> 
> For vDPA/vhost-user:
> 
>     Invalid tx_queue_size (= 2048), must be a power of 2 between 256 and 1024
> 
> For all the others:
> 
>     Invalid tx_queue_size (= 512), must be a power of 2 between 256 and 256
> 
> Fixes: 2eef278b9e63 ("virtio-net: fix tx queue size for !vhost-user")
> Cc: mst@redhat.com
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

> ---
>  hw/net/virtio-net.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 6df6b7329d25..e9905aac83ad 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -3630,12 +3630,12 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
>      }
>  
>      if (n->net_conf.tx_queue_size < VIRTIO_NET_TX_QUEUE_MIN_SIZE ||
> -        n->net_conf.tx_queue_size > VIRTQUEUE_MAX_SIZE ||
> +        n->net_conf.tx_queue_size > virtio_net_max_tx_queue_size(n) ||
>          !is_power_of_2(n->net_conf.tx_queue_size)) {
>          error_setg(errp, "Invalid tx_queue_size (= %" PRIu16 "), "
>                     "must be a power of 2 between %d and %d",
>                     n->net_conf.tx_queue_size, VIRTIO_NET_TX_QUEUE_MIN_SIZE,
> -                   VIRTQUEUE_MAX_SIZE);
> +                   virtio_net_max_tx_queue_size(n));
>          virtio_cleanup(vdev);
>          return;
>      }
> -- 
> 2.39.2
Re: [PATCH] virtio-net: correctly report maximum tx_queue_size value
Posted by Jason Wang 11 months ago 
On Mon, Jun 5, 2023 at 10:22 PM Laurent Vivier <lvivier@redhat.com> wrote:
>
> Maximum value for tx_queue_size depends on the backend type.
> 1024 for vDPA/vhost-user, 256 for all the others.
>
> The value is returned by virtio_net_max_tx_queue_size() to set the
> parameter:
>
>     n->net_conf.tx_queue_size = MIN(virtio_net_max_tx_queue_size(n),
>                                     n->net_conf.tx_queue_size);
>
> But the parameter checking uses VIRTQUEUE_MAX_SIZE (1024).
>
> So the parameter is silently ignored and ethtool reports a different
> value than the one provided by the user.
>
>    ... -netdev tap,... -device virtio-net,tx_queue_size=1024
>
>     # ethtool -g enp0s2
>     Ring parameters for enp0s2:
>     Pre-set maximums:
>     RX:         256
>     RX Mini:    n/a
>     RX Jumbo:   n/a
>     TX:         256
>     Current hardware settings:
>     RX:         256
>     RX Mini:    n/a
>     RX Jumbo:   n/a
>     TX:         256
>
>    ... -netdev vhost-user,... -device virtio-net,tx_queue_size=2048
>
>     Invalid tx_queue_size (= 2048), must be a power of 2 between 256 and 1024
>
> With this patch the correct maximum value is checked and displayed.
>
> For vDPA/vhost-user:
>
>     Invalid tx_queue_size (= 2048), must be a power of 2 between 256 and 1024
>
> For all the others:
>
>     Invalid tx_queue_size (= 512), must be a power of 2 between 256 and 256
>
> Fixes: 2eef278b9e63 ("virtio-net: fix tx queue size for !vhost-user")
> Cc: mst@redhat.com
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Queued.

Thanks

> ---
>  hw/net/virtio-net.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 6df6b7329d25..e9905aac83ad 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -3630,12 +3630,12 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
>      }
>
>      if (n->net_conf.tx_queue_size < VIRTIO_NET_TX_QUEUE_MIN_SIZE ||
> -        n->net_conf.tx_queue_size > VIRTQUEUE_MAX_SIZE ||
> +        n->net_conf.tx_queue_size > virtio_net_max_tx_queue_size(n) ||
>          !is_power_of_2(n->net_conf.tx_queue_size)) {
>          error_setg(errp, "Invalid tx_queue_size (= %" PRIu16 "), "
>                     "must be a power of 2 between %d and %d",
>                     n->net_conf.tx_queue_size, VIRTIO_NET_TX_QUEUE_MIN_SIZE,
> -                   VIRTQUEUE_MAX_SIZE);
> +                   virtio_net_max_tx_queue_size(n));
>          virtio_cleanup(vdev);
>          return;
>      }
> --
> 2.39.2
>
>

Patchew 2.1-devel-0870f84

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