From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>, dev@dpdk.org
Cc: Yuanhan Liu <yliu@fridaylinux.org>
Subject: Re: [dpdk-dev] [PATCH 2/2] vhost: only drop vqs with built-in virtio_net.c driver
Date: Wed, 31 Jan 2018 19:07:50 +0100 [thread overview]
Message-ID: <0032747e-c981-ebd8-357b-b24122c89993@redhat.com> (raw)
In-Reply-To: <20180131174651.6386-3-stefanha@redhat.com>
Hi Stefan,
On 01/31/2018 06:46 PM, Stefan Hajnoczi wrote:
> Commit e29109323595beb3884da58126ebb3b878cb66f5 ("vhost: destroy unused
> virtqueues when multiqueue not negotiated") broke vhost-scsi by removing
> virtqueues when the virtio-net-specific VIRTIO_NET_F_MQ feature bit is
> missing.
>
> The vhost_user.c code shouldn't assume all devices are vhost net device
> backends. Use the new VIRTIO_DEV_BUILTIN_VIRTIO_NET flag to check
> whether virtio_net.c is being used.
>
> This fixes examples/vhost_scsi.
>
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
> lib/librte_vhost/vhost_user.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index 1dd1a61b6..65ee33919 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -187,7 +187,8 @@ vhost_user_set_features(struct virtio_net *dev, uint64_t features)
> (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ? "on" : "off",
> (dev->features & (1ULL << VIRTIO_F_VERSION_1)) ? "on" : "off");
>
> - if (!(dev->features & (1ULL << VIRTIO_NET_F_MQ))) {
> + if ((dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET) &&
> + !(dev->features & (1ULL << VIRTIO_NET_F_MQ))) {
If we had an external net backend using the library, we would also need
to remove extra queues if it advertised VIRTIO_NET_F_MQ, but the feature
isn't negotiated.
In this case, the fix I suggested yesterday would work:
if ((vhost_features & (1ULL << VIRTIO_NET_F_MQ)) &&
!(dev->features & (1ULL << VIRTIO_NET_F_MQ)) {
...
}
For any backend that does not advertise the feature, no queues will be
destroyed.
Thanks,
Maxime
> /*
> * Remove all but first queue pair if MQ hasn't been
> * negotiated. This is safe because the device is not
>
next prev parent reply other threads:[~2018-01-31 18:07 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-31 17:46 [dpdk-dev] [PATCH 0/2] vhost: fix VIRTIO_NET_F_MQ vhost_scsi breakage Stefan Hajnoczi
2018-01-31 17:46 ` [dpdk-dev] [PATCH 1/2] vhost: add flag for built-in virtio_net.c driver Stefan Hajnoczi
2018-02-01 14:46 ` Yuanhan Liu
2018-01-31 17:46 ` [dpdk-dev] [PATCH 2/2] vhost: only drop vqs with " Stefan Hajnoczi
2018-01-31 18:07 ` Maxime Coquelin [this message]
[not found] ` <20180201102428.GA5783@stefanha-x1.localdomain>
2018-02-01 12:49 ` Maxime Coquelin
2018-02-01 12:58 ` [dpdk-dev] [PATCH 0/2] vhost: fix VIRTIO_NET_F_MQ vhost_scsi breakage Maxime Coquelin
2018-02-05 14:20 ` Ferruh Yigit
2018-02-01 14:46 ` Yuanhan Liu
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