From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41111) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dFllM-0007ig-3r for qemu-devel@nongnu.org; Tue, 30 May 2017 14:21:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dFllI-0006Bh-4z for qemu-devel@nongnu.org; Tue, 30 May 2017 14:21:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49968) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dFllH-0006BW-Pv for qemu-devel@nongnu.org; Tue, 30 May 2017 14:20:56 -0400 Date: Tue, 30 May 2017 21:20:45 +0300 From: "Michael S. Tsirkin" Message-ID: <20170530211819-mutt-send-email-mst@kernel.org> References: <20170526142858.19931-1-maxime.coquelin@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20170526142858.19931-1-maxime.coquelin@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v2 0/6] vhost-user: Specify and implement device IOTLB support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Maxime Coquelin Cc: peterx@redhat.com, marcandre.lureau@gmail.com, vkaplans@redhat.com, jasowang@redhat.com, wexu@redhat.com, yuanhan.liu@linux.intel.com, qemu-devel@nongnu.org, jfreiman@redhat.com On Fri, May 26, 2017 at 04:28:52PM +0200, Maxime Coquelin wrote: > This series aims at specifying ans implementing the protocol update > required to support device IOTLB with user backends. >=20 > In this second non-RFC version, main changes are: > - spec fixes and clarification > - rings information update has been restored back to ring enablement t= ime > - Work around GCC 4.4.7 limitation wrt assignment in unnamed union at > declaration time. >=20 > The series can be tested with vhost_iotlb_proto_v2 branch on my gitlab > account[0]. >=20 > The slave requests channel part is re-used from Marc-Andr=E9's series s= ubmitted > last year[1], with main changes from original version being request/fea= ture > names renaming and addition of the REPLY_ACK feature support. >=20 > Regarding IOTLB protocol, one noticeable change is the IOTLB miss reque= st > 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. >=20 > 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. >=20 > [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.htm= l Overall, this looks good to me. I do think patch 3 isn't a good idea though, if slave wants something let it request it. Need to find out why does vhost in kernel want the used ring iotlb at start time - especially considering we aren't even guaranteed one entry covers the whole ring, and invalidates should affect all addresses at least in theory. > Marc-Andr=E9 Lureau (2): > vhost-user: add vhost_user to hold the chr > vhost-user: add slave-req-fd support >=20 > 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 >=20 > 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(-) >=20 > --=20 > 2.9.4