DPDK patches and discussions
 help / color / mirror / Atom feed
From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: dev@dpdk.org, yliu@fridaylinux.org, tiwei.bie@intel.com,
	jianfeng.tan@intel.com, lprosek@redhat.com, lersek@redhat.com
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Subject: [dpdk-dev] [PATCH v3 1/4] vhost: prevent features to be changed while device is running
Date: Wed,  6 Dec 2017 10:20:45 +0100	[thread overview]
Message-ID: <20171206092048.3568-2-maxime.coquelin@redhat.com> (raw)
In-Reply-To: <20171206092048.3568-1-maxime.coquelin@redhat.com>

As section 2.2 of the Virtio spec states about features
negotiation:
"During device initialization, the driver reads this and tells
the device the subset that it accepts. The only way to
renegotiate is to reset the device."

This patch implements a check to prevent illegal features change
while the device is running.

One exception is the VHOST_F_LOG_ALL feature bit, which is enabled
when live-migration is initiated. But this feature is not negotiated
with the Virtio driver, but directly with the Vhost master.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 lib/librte_vhost/vhost_user.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index f4c7ce462..2d86c0ca8 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -183,7 +183,22 @@ vhost_user_set_features(struct virtio_net *dev, uint64_t features)
 		return -1;
 	}
 
-	if ((dev->flags & VIRTIO_DEV_RUNNING) && dev->features != features) {
+	if (dev->features == features)
+		return 0;
+
+	if (dev->flags & VIRTIO_DEV_RUNNING) {
+		/*
+		 * Error out if master tries to change features while device is
+		 * in running state. The exception being VHOST_F_LOG_ALL, which
+		 * is enabled when the live-migration starts.
+		 */
+		if ((dev->features ^ features) & ~(1ULL << VHOST_F_LOG_ALL)) {
+			RTE_LOG(ERR, VHOST_CONFIG,
+				"(%d) features changed while device is running.\n",
+				dev->vid);
+			return -1;
+		}
+
 		if (dev->notify_ops->features_changed)
 			dev->notify_ops->features_changed(dev->vid, features);
 	}
-- 
2.14.3

  reply	other threads:[~2017-12-06  9:21 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-06  9:20 [dpdk-dev] [PATCH v3 0/4] Vhost: fix mq=on but VIRTIO_NET_F_MQ not negotiated Maxime Coquelin
2017-12-06  9:20 ` Maxime Coquelin [this message]
2017-12-07  8:08   ` [dpdk-dev] [PATCH v3 1/4] vhost: prevent features to be changed while device is running Tiwei Bie
2017-12-07  8:39     ` Maxime Coquelin
2017-12-07 10:29       ` Tiwei Bie
2017-12-06  9:20 ` [dpdk-dev] [PATCH v3 2/4] vhost: propagate VHOST_USER_SET_FEATURES handling error Maxime Coquelin
2017-12-06  9:20 ` [dpdk-dev] [PATCH v3 3/4] vhost: extract virtqueue cleaning and freeing functions Maxime Coquelin
2017-12-06  9:20 ` [dpdk-dev] [PATCH v3 4/4] vhost: destroy unused virtqueues when multiqueue not negotiated Maxime Coquelin
2017-12-06 11:40 ` [dpdk-dev] [PATCH v3 0/4] Vhost: fix mq=on but VIRTIO_NET_F_MQ " Laszlo Ersek
2017-12-06 12:25 ` Ladi Prosek

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20171206092048.3568-2-maxime.coquelin@redhat.com \
    --to=maxime.coquelin@redhat.com \
    --cc=dev@dpdk.org \
    --cc=jianfeng.tan@intel.com \
    --cc=lersek@redhat.com \
    --cc=lprosek@redhat.com \
    --cc=tiwei.bie@intel.com \
    --cc=yliu@fridaylinux.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).