From: Laszlo Ersek <lersek@redhat.com>
To: Maxime Coquelin <maxime.coquelin@redhat.com>,
dev@dpdk.org, yliu@fridaylinux.org, tiwei.bie@intel.com,
jianfeng.tan@intel.com, lprosek@redhat.com
Subject: Re: [dpdk-dev] [PATCH v4 0/4] Vhost: fix mq=on but VIRTIO_NET_F_MQ not negotiated
Date: Mon, 11 Dec 2017 17:12:57 +0100 [thread overview]
Message-ID: <83b1a5dc-ca4e-3768-ad2e-b2fa4d2c432b@redhat.com> (raw)
In-Reply-To: <20171211151503.19195-1-maxime.coquelin@redhat.com>
On 12/11/17 16:14, Maxime Coquelin wrote:
> Hi,
>
> This fourth revision fixes patch 1 by not returning early in
> SET_FEATURE handling if new features bitfield is same as previous
> one. Indeed, as reported by Tiwei, in case negotiated features is 0,
> it would return early whereas it should set the Vnet header len.
> The change consists in returning early when features are equal only
> when the device is un running state.
> I did not applied Laszlo's Acked-by and Ladi's Tested-by because of
> this change. This new iteration has been tested locally using iPXE.
>
> Having QEMU started with mq=on but guest driver not negotiating
> VIRTIO_NET_F_MQ feature ends up in the vhost device to never
> start. Indeed, more queues are created in the vhost backend than
> configured.
>
> Guest drivers known to not advertise the VIRTIO_NET_F_MQ feature are
> iPXE and OVMF Virtio-net drivers.
>
> Queues are created because before starting the guest, QEMU sends
> VHOST_USER_SET_VRING_CALL requests for all queues declared in QEMU
> command line. Also, once Virtio features negotiated, QEMU sends
> VHOST_USER_SET_VRING_ENABLE requests to disable all but the first
> queue pair.
>
> This series fixes this by destroying all but first queue pair in
> the backend if VIRTIO_NET_F_MQ isn't negotiated. First patches
> makes sure that VHOST_USER_SET_FEATURES request doesn't change
> Virtio features while the device is running, which should never
> happen as per the Virtio spec. This helps to make sure vitqueues
> aren't destroyed while being processed, but also protect from
> other illegal features changes (e.g. VIRTIO_NET_F_MRG_RXBUF).
>
> Changes since v3:
> =================
> - Fix Virtio features = 0 case (Tiwei)
> Changes since v2:
> =================
> - Patch 2: Rework & fix VQs destruction loop (Laszlo)
> Changes since v1:
> =================
> - Patch 1: shift bits in the right direction (Ladi)
>
> Maxime Coquelin (4):
> vhost: prevent features to be changed while device is running
> vhost: propagate VHOST_USER_SET_FEATURES handling error
> vhost: extract virtqueue cleaning and freeing functions
> vhost: destroy unused virtqueues when multiqueue not negotiated
>
> lib/librte_vhost/vhost.c | 22 ++++++++++++----------
> lib/librte_vhost/vhost.h | 3 +++
> lib/librte_vhost/vhost_user.c | 39 +++++++++++++++++++++++++++++++++++++--
> 3 files changed, 52 insertions(+), 12 deletions(-)
>
I compared patch #1 between v3 and v4 -- I think you could have carried
forward my A-b. (Perhaps a more thorough R-b should have been dropped
indeed.) Anyways, for v4:
Acked-by: Laszlo Ersek <lersek@redhat.com>
Thanks
Laszlo
next prev parent reply other threads:[~2017-12-11 16:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-11 15:14 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
2017-12-13 8:14 ` Maxime Coquelin
2017-12-11 16:12 ` Laszlo Ersek [this message]
2017-12-12 6:34 ` [dpdk-dev] [PATCH v4 0/4] Vhost: fix mq=on but VIRTIO_NET_F_MQ " Ladi Prosek
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