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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Eli Cohen <elic@nvidia.com>
Cc: jasowang@redhat.com, virtualization@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org, lulu@redhat.com
Subject: Re: [PATCH] vdpa/mlx5: Use random MAC for the vdpa net instance
Date: Sun, 29 Nov 2020 15:08:22 -0500	[thread overview]
Message-ID: <20201129150505-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20201129064351.63618-1-elic@nvidia.com>

On Sun, Nov 29, 2020 at 08:43:51AM +0200, Eli Cohen wrote:
> We should not try to use the VF MAC address as that is used by the
> regular (e.g. mlx5_core) NIC implementation. Instead, use a random
> generated MAC address.
> 
> Suggested by: Cindy Lu <lulu@redhat.com>
> Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
> Signed-off-by: Eli Cohen <elic@nvidia.com>

I didn't realise it's possible to use VF in two ways
with and without vdpa.
Could you include a bit more description on the failure
mode?
Is switching to a random mac for such an unusual
configuration really justified?
It looks like changing a MAC could break some guests,
can it not?

> ---
>  drivers/vdpa/mlx5/net/mlx5_vnet.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 1fa6fcac8299..80d06d958b8b 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1955,10 +1955,7 @@ void *mlx5_vdpa_add_dev(struct mlx5_core_dev *mdev)
>  	if (err)
>  		goto err_mtu;
>  
> -	err = mlx5_query_nic_vport_mac_address(mdev, 0, 0, config->mac);
> -	if (err)
> -		goto err_mtu;
> -
> +	eth_random_addr(config->mac);
>  	mvdev->vdev.dma_dev = mdev->device;
>  	err = mlx5_vdpa_alloc_resources(&ndev->mvdev);
>  	if (err)
> -- 
> 2.26.2


WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Eli Cohen <elic@nvidia.com>
Cc: linux-kernel@vger.kernel.org, lulu@redhat.com,
	virtualization@lists.linux-foundation.org
Subject: Re: [PATCH] vdpa/mlx5: Use random MAC for the vdpa net instance
Date: Sun, 29 Nov 2020 15:08:22 -0500	[thread overview]
Message-ID: <20201129150505-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20201129064351.63618-1-elic@nvidia.com>

On Sun, Nov 29, 2020 at 08:43:51AM +0200, Eli Cohen wrote:
> We should not try to use the VF MAC address as that is used by the
> regular (e.g. mlx5_core) NIC implementation. Instead, use a random
> generated MAC address.
> 
> Suggested by: Cindy Lu <lulu@redhat.com>
> Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
> Signed-off-by: Eli Cohen <elic@nvidia.com>

I didn't realise it's possible to use VF in two ways
with and without vdpa.
Could you include a bit more description on the failure
mode?
Is switching to a random mac for such an unusual
configuration really justified?
It looks like changing a MAC could break some guests,
can it not?

> ---
>  drivers/vdpa/mlx5/net/mlx5_vnet.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 1fa6fcac8299..80d06d958b8b 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1955,10 +1955,7 @@ void *mlx5_vdpa_add_dev(struct mlx5_core_dev *mdev)
>  	if (err)
>  		goto err_mtu;
>  
> -	err = mlx5_query_nic_vport_mac_address(mdev, 0, 0, config->mac);
> -	if (err)
> -		goto err_mtu;
> -
> +	eth_random_addr(config->mac);
>  	mvdev->vdev.dma_dev = mdev->device;
>  	err = mlx5_vdpa_alloc_resources(&ndev->mvdev);
>  	if (err)
> -- 
> 2.26.2

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  reply	other threads:[~2020-11-29 20:10 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-29  6:43 [PATCH] vdpa/mlx5: Use random MAC for the vdpa net instance Eli Cohen
2020-11-29 20:08 ` Michael S. Tsirkin [this message]
2020-11-29 20:08   ` Michael S. Tsirkin
2020-11-30  6:27   ` Eli Cohen
2020-11-30  9:00     ` Michael S. Tsirkin
2020-11-30  9:00       ` Michael S. Tsirkin
2020-11-30  9:27       ` Eli Cohen
2020-11-30  9:33         ` Michael S. Tsirkin
2020-11-30  9:33           ` Michael S. Tsirkin
2020-11-30 10:41           ` Cindy Lu
2020-11-30 15:33             ` Michael S. Tsirkin
2020-11-30 15:33               ` Michael S. Tsirkin
2020-12-01  9:23               ` Cindy Lu
2020-12-01 11:32                 ` Michael S. Tsirkin
2020-12-01 11:32                   ` Michael S. Tsirkin
2020-12-02  2:27                   ` Cindy Lu
2020-12-02  4:18                 ` Jason Wang
2020-12-02  4:18                   ` Jason Wang
2020-12-02  5:57                   ` Eli Cohen
2020-12-02  9:23                     ` Michael S. Tsirkin
2020-12-02  9:23                       ` Michael S. Tsirkin
2020-12-02 12:12                       ` Eli Cohen
2020-12-02 12:17                         ` Michael S. Tsirkin
2020-12-02 12:17                           ` Michael S. Tsirkin
2020-12-02 13:00                           ` Jason Wang
2020-12-02 13:00                             ` Jason Wang
2020-12-02 13:07                             ` Michael S. Tsirkin
2020-12-02 13:07                               ` Michael S. Tsirkin
2020-12-02 13:33                               ` Jason Wang
2020-12-02 13:33                                 ` Jason Wang
2020-12-02 13:48                       ` Jason Wang
2020-12-02 13:48                         ` Jason Wang
2020-12-02 22:00                         ` Michael S. Tsirkin
2020-12-02 22:00                           ` Michael S. Tsirkin
2020-12-03  6:49                           ` Eli Cohen
2020-12-03 10:44                             ` Michael S. Tsirkin
2020-12-03 10:44                               ` Michael S. Tsirkin
2020-12-03 12:09                               ` Eli Cohen
2020-12-03 12:15                                 ` Michael S. Tsirkin
2020-12-03 12:15                                   ` Michael S. Tsirkin
2020-12-03 12:24                                   ` Eli Cohen
2020-12-04  2:53                                     ` Jason Wang
2020-12-04  2:53                                       ` Jason Wang
2020-12-06  6:54                                       ` Eli Cohen
2020-12-02  9:30                   ` Michael S. Tsirkin
2020-12-02  9:30                     ` Michael S. Tsirkin
2020-12-02 12:56                     ` Jason Wang
2020-12-02 12:56                       ` Jason Wang
2020-12-02 13:04                       ` Michael S. Tsirkin
2020-12-02 13:04                         ` Michael S. Tsirkin
2020-12-02 13:41                         ` Jason Wang
2020-12-02 13:41                           ` Jason Wang
2020-11-30 11:51           ` Eli Cohen
2020-11-30 15:30             ` Michael S. Tsirkin
2020-11-30 15:30               ` Michael S. Tsirkin

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