As announced during v20.05 release cycle, this
patch makes reply-ack protocol feature to be enabled
unconditionally.
This protocol feature makes the communication between the
master and the slave more robust, avoiding for example
possible undefined behaviour with VHOST_USER_SET_MEM_TABLE.
Also, reply-ack support will be required for upcoming
VHOST_USER_SET_STATUS request.
Note that this protocol feature was disabled by default
because Qemu version 2.7.0 to 2.9.0 had a bug causing a
deadlock when reply-ack was negotiated and multiqueue
enabled. These Qemu version are now very old and no more
maintained, so we can resonnably consider we no more
support them.
Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
---
v2:
- Fix commit message
- Remove mention to the workaround in the doc
doc/guides/prog_guide/vhost_lib.rst | 5 -----
lib/librte_vhost/vhost_user.c | 9 ---------
2 files changed, 14 deletions(-)
diff --git a/doc/guides/prog_guide/vhost_lib.rst
b/doc/guides/prog_guide/vhost_lib.rst
index 07e40e3c5e..db921f922b 100644
--- a/doc/guides/prog_guide/vhost_lib.rst
+++ b/doc/guides/prog_guide/vhost_lib.rst
@@ -104,11 +104,6 @@ The following is an overview of some key Vhost API
functions:
from accessing memory the virtio device isn't allowed to, when the feature
is negotiated and an IOMMU device is declared.
- However, this feature enables vhost-user's reply-ack protocol feature,
- which implementation is buggy in Qemu v2.7.0-v2.9.0 when doing multiqueue.
- Enabling this flag with these Qemu version results in Qemu being blocked
- when multiple queue pairs are declared.
-
- ``RTE_VHOST_USER_POSTCOPY_SUPPORT``
Postcopy live-migration support will be enabled when this flag is set.
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 84bebad792..ea9cd107b9 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -2012,15 +2012,6 @@ vhost_user_get_protocol_features(struct virtio_net
**pdev,
rte_vhost_driver_get_features(dev->ifname, &features);
rte_vhost_driver_get_protocol_features(dev->ifname, &protocol_features);
- /*
- * REPLY_ACK protocol feature is only mandatory for now
- * for IOMMU feature. If IOMMU is explicitly disabled by the
- * application, disable also REPLY_ACK feature for older buggy
- * Qemu versions (from v2.7.0 to v2.9.0).
- */
- if (!(features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)))
- protocol_features &= ~(1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK);
-
msg->payload.u64 = protocol_features;
msg->size = sizeof(msg->payload.u64);
msg->fd_num = 0;
--
2.26.2
