From: Tiwei Bie <tiwei.bie@intel.com>
To: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: dev@dpdk.org, yliu@fridaylinux.org, jianfeng.tan@intel.com,
lprosek@redhat.com, lersek@redhat.com
Subject: Re: [dpdk-dev] [PATCH v4 4/4] vhost: destroy unused virtqueues when multiqueue not negotiated
Date: Wed, 13 Dec 2017 11:16:15 +0800 [thread overview]
Message-ID: <20171213031615.t7rh2ccjf5gml73h@debian-xvivbkq> (raw)
In-Reply-To: <20171211151503.19195-5-maxime.coquelin@redhat.com>
On Mon, Dec 11, 2017 at 04:15:03PM +0100, Maxime Coquelin wrote:
> QEMU sends VHOST_USER_SET_VRING_CALL requests for all queues
> declared in QEMU command line before the guest is started.
> It has the effect in DPDK vhost-user backend to allocate vrings
> for all queues declared by QEMU.
>
> If the first driver being used does not support multiqueue,
> the device never changes to VIRTIO_DEV_RUNNING state as only
> the first queue pair is initialized. One driver impacted by
> this bug is virtio-net's iPXE driver which does not support
> VIRTIO_NET_F_MQ feature.
>
> It is safe to destroy unused virtqueues in SET_FEATURES request
> handler, as it is ensured the device is not in running state
> at this stage, so virtqueues aren't being processed.
>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
> lib/librte_vhost/vhost_user.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index 471b1612c..d5ca1ac90 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -216,6 +216,24 @@ 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))) {
> + /*
> + * Remove all but first queue pair if MQ hasn't been
> + * negotiated. This is safe because the device is not
> + * running at this stage.
> + */
> + while (dev->nr_vring > 2) {
> + struct vhost_virtqueue *vq;
> +
> + vq = dev->virtqueue[--dev->nr_vring];
> + if (!vq)
> + continue;
> +
> + cleanup_vq(vq, 1);
> + free_vq(vq);
Hi,
Sorry, I didn't look into this patch in last version.
The freed dev->virtqueue[$idx] also needs to be zeroed.
Otherwise, it won't be allocated in the future due to the
below check in vhost_user_check_and_alloc_queue_pair(),
and the freed memory will be used again.
/*
* Allocate a queue pair if it hasn't been allocated yet
*/
static int
vhost_user_check_and_alloc_queue_pair(struct virtio_net *dev, VhostUserMsg *msg)
{
........
if (dev->virtqueue[vring_idx])
return 0;
return alloc_vring_queue(dev, vring_idx);
}
Best regards,
Tiwei Bie
> + }
> + }
> +
> return 0;
> }
>
> --
> 2.14.3
>
next prev parent reply other threads:[~2017-12-13 3:16 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-11 15:14 [dpdk-dev] [PATCH v4 0/4] Vhost: fix mq=on but VIRTIO_NET_F_MQ " Maxime Coquelin
2017-12-11 15:15 ` [dpdk-dev] [PATCH v4 1/4] vhost: prevent features to be changed while device is running Maxime Coquelin
2017-12-11 15:15 ` [dpdk-dev] [PATCH v4 2/4] vhost: propagate VHOST_USER_SET_FEATURES handling error Maxime Coquelin
2017-12-11 15:15 ` [dpdk-dev] [PATCH v4 3/4] vhost: extract virtqueue cleaning and freeing functions Maxime Coquelin
2017-12-11 15:15 ` [dpdk-dev] [PATCH v4 4/4] vhost: destroy unused virtqueues when multiqueue not negotiated Maxime Coquelin
2017-12-13 3:16 ` Tiwei Bie [this message]
2017-12-13 8:14 ` Maxime Coquelin
2017-12-11 16:12 ` [dpdk-dev] [PATCH v4 0/4] Vhost: fix mq=on but VIRTIO_NET_F_MQ " Laszlo Ersek
2017-12-12 6:34 ` Ladi Prosek
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