Re: [Qemu-devel] [PATCH v2 0/6] vhost-user: Specify and implement device IOTLB support

[Maxime Coquelin <maxime.coquelin@redhat.com>]

Hi,

On 05/26/2017 04:28 PM, Maxime Coquelin wrote:
> This series aims at specifying ans implementing the protocol update
> required to support device IOTLB with user backends.
> 
> In this second non-RFC version, main changes are:
>   - spec fixes and clarification
>   - rings information update has been restored back to ring enablement time
>   - Work around GCC 4.4.7 limitation wrt assignment in unnamed union at
> declaration time.
> 
> The series can be tested with vhost_iotlb_proto_v2 branch on my gitlab
> account[0].
> 
> The slave requests channel part is re-used from Marc-André's series submitted
> last year[1], with main changes from original version being request/feature
> names renaming and addition of the REPLY_ACK feature support.
> 
> Regarding IOTLB protocol, one noticeable change is the IOTLB miss request
> reply made optionnal (i.e. only if slave requests it by setting the
> VHOST_USER_NEED_REPLY flag in the message header). This change provides
> more flexibility in the backend implementation of the feature.
> 
> The protocol is very close to kernel backends, except that a new
> communication channel is introduced to enable the slave to send
> requests to the master.
> 
> [0]: https://gitlab.com/mcoquelin/dpdk-next-virtio/commits/vhost_iotlb_proto_v2
> [1]: https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg00095.html
> 
> Marc-André Lureau (2):
>    vhost-user: add vhost_user to hold the chr
>    vhost-user: add slave-req-fd support
> 
> Maxime Coquelin (4):
>    vhost: propagate errors in vhost_device_iotlb_miss()
>    vhost: rework IOTLB messaging
>    vhost: extend ring information update for IOTLB to all rings
>    spec/vhost-user spec: Add IOMMU support
> 
>   docs/specs/vhost-user.txt         | 118 ++++++++++++++++++++++++-
>   hw/virtio/vhost-backend.c         | 130 ++++++++++++++++------------
>   hw/virtio/vhost-user.c            | 177 +++++++++++++++++++++++++++++++++++++-
>   hw/virtio/vhost.c                 |  27 ++++--
>   include/hw/virtio/vhost-backend.h |  23 +++--
>   include/hw/virtio/vhost.h         |   2 +-
>   6 files changed, 397 insertions(+), 80 deletions(-)
> 

I just noticed I missed the below change in the series.
I'll wait v2 is reviewed before posting the v3, or I can post v3 now if
you prefer.

Regards,
Maxime

------------------------------------------------------------------

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 22874a9..e037db6 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -77,6 +77,7 @@ static const int user_feature_bits[] = {
      VIRTIO_NET_F_HOST_UFO,
      VIRTIO_NET_F_MRG_RXBUF,
      VIRTIO_NET_F_MTU,
+    VIRTIO_F_IOMMU_PLATFORM,

      /* This bit implies RARP isn't sent by QEMU out of band */
      VIRTIO_NET_F_GUEST_ANNOUNCE,