From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47862) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cxvVs-0005C8-HF for qemu-devel@nongnu.org; Tue, 11 Apr 2017 09:07:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cxvVq-0003Gu-7E for qemu-devel@nongnu.org; Tue, 11 Apr 2017 09:07:16 -0400 Received: from mail-lf0-x241.google.com ([2a00:1450:4010:c07::241]:35934) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1cxvVp-0003GL-Fg for qemu-devel@nongnu.org; Tue, 11 Apr 2017 09:07:13 -0400 Received: by mail-lf0-x241.google.com with SMTP id 75so5780063lfs.3 for ; Tue, 11 Apr 2017 06:07:11 -0700 (PDT) MIME-Version: 1.0 References: <20170411101002.28451-1-maxime.coquelin@redhat.com> <20170411101002.28451-2-maxime.coquelin@redhat.com> In-Reply-To: <20170411101002.28451-2-maxime.coquelin@redhat.com> From: =?UTF-8?B?TWFyYy1BbmRyw6kgTHVyZWF1?= Date: Tue, 11 Apr 2017 13:06:59 +0000 Message-ID: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [RFC 1/2] spec/vhost-user: Introduce secondary channel for slave initiated requests List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Maxime Coquelin , mst@redhat.com, vkaplans@redhat.com, jasowang@redhat.com, wexu@redhat.com, peterx@redhat.com, yuanhan.liu@linux.intel.com, virtio-comment@lists.oasis-open.org, qemu-devel@nongnu.org Hi On Tue, Apr 11, 2017 at 12:10 PM Maxime Coquelin wrote: > This vhost-user specification update aims at enabling the > slave to send requests to the master using a dedicated socket > created by the master. > > It can be used for example when the slave implements a device > IOTLB to send cache miss requests to the master. > > The message types list is updated with an "Initiator" field to > indicate for each type whether the master and/or slave can > initiate the request. > > Signed-off-by: Maxime Coquelin > This is very similar to a patch I proposed for shutdown slave initiated requests: https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg00095.html > --- > docs/specs/vhost-user.txt | 38 ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 38 insertions(+) > > diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt > index 036890f..b365047 100644 > --- a/docs/specs/vhost-user.txt > +++ b/docs/specs/vhost-user.txt > @@ -139,6 +139,7 @@ in the ancillary data: > * VHOST_USER_SET_VRING_KICK > * VHOST_USER_SET_VRING_CALL > * VHOST_USER_SET_VRING_ERR > + * VHOST_USER_SET_SLAVE_REQ_FD > > I like "slave-req-fd" better than "slave-fd" > If Master is unable to send the full message or receives a wrong reply i= t > will > close the connection. An optional reconnection mechanism can be > implemented. > @@ -150,6 +151,11 @@ As older slaves don't support negotiating protocol > features, > a feature bit was dedicated for this purpose: > #define VHOST_USER_F_PROTOCOL_FEATURES 30 > > +If the slave supports VHOST_USER_PROTOCOL_F_SLAVE_REQ protocol feature, > the > +master may create a secondary Unix domain socket and send its file > descriptor > +to the slave using VHOST_USER_SET_SLAVE_REQ_FD request. This new channel > enables > +the slave to send message requests and master to send message replies. > + > Starting and stopping rings > ---------------------- > Client must only process each ring when it is started. > @@ -260,6 +266,7 @@ Protocol features > #define VHOST_USER_PROTOCOL_F_RARP 2 > #define VHOST_USER_PROTOCOL_F_REPLY_ACK 3 > #define VHOST_USER_PROTOCOL_F_MTU 4 > +#define VHOST_USER_PROTOCOL_F_SLAVE_REQ 5 > > Message types > ------------- > @@ -268,6 +275,7 @@ Message types > > Id: 1 > Equivalent ioctl: VHOST_GET_FEATURES > + Initiator: Master > Master payload: N/A > Slave payload: u64 > > @@ -279,6 +287,7 @@ Message types > > Id: 2 > Ioctl: VHOST_SET_FEATURES > + Initiator: Master > Master payload: u64 > > Enable features in the underlying vhost implementation using a > bitmask. > @@ -289,6 +298,7 @@ Message types > > Id: 15 > Equivalent ioctl: VHOST_GET_FEATURES > + Initiator: Master > Master payload: N/A > Slave payload: u64 > > @@ -302,6 +312,7 @@ Message types > > Id: 16 > Ioctl: VHOST_SET_FEATURES > + Initiator: Master > Master payload: u64 > > Enable protocol features in the underlying vhost implementation. > @@ -314,6 +325,7 @@ Message types > > Id: 3 > Equivalent ioctl: VHOST_SET_OWNER > + Initiator: Master > Master payload: N/A > > Issued when a new connection is established. It sets the current > Master > @@ -323,6 +335,7 @@ Message types > * VHOST_USER_RESET_OWNER > > Id: 4 > + Initiator: Master > Master payload: N/A > > This is no longer used. Used to be sent to request disabling > @@ -335,6 +348,7 @@ Message types > > Id: 5 > Equivalent ioctl: VHOST_SET_MEM_TABLE > + Initiator: Master > Master payload: memory regions description > > Sets the memory map regions on the slave so it can translate the > vring > @@ -346,6 +360,7 @@ Message types > > Id: 6 > Equivalent ioctl: VHOST_SET_LOG_BASE > + Initiator: Master > Master payload: u64 > Slave payload: N/A > > @@ -360,6 +375,7 @@ Message types > > Id: 7 > Equivalent ioctl: VHOST_SET_LOG_FD > + Initiator: Master > Master payload: N/A > > Sets the logging file descriptor, which is passed as ancillary dat= a. > @@ -368,6 +384,7 @@ Message types > > Id: 8 > Equivalent ioctl: VHOST_SET_VRING_NUM > + Initiator: Master > Master payload: vring state description > > Set the size of the queue. > @@ -376,6 +393,7 @@ Message types > > Id: 9 > Equivalent ioctl: VHOST_SET_VRING_ADDR > + Initiator: Master > Master payload: vring address description > Slave payload: N/A > > @@ -385,6 +403,7 @@ Message types > > Id: 10 > Equivalent ioctl: VHOST_SET_VRING_BASE > + Initiator: Master > Master payload: vring state description > > Sets the base offset in the available vring. > @@ -393,6 +412,7 @@ Message types > > Id: 11 > Equivalent ioctl: VHOST_USER_GET_VRING_BASE > + Initiator: Master > Master payload: vring state description > Slave payload: vring state description > > @@ -402,6 +422,7 @@ Message types > > Id: 12 > Equivalent ioctl: VHOST_SET_VRING_KICK > + Initiator: Master > Master payload: u64 > > Set the event file descriptor for adding buffers to the vring. It > @@ -415,6 +436,7 @@ Message types > > Id: 13 > Equivalent ioctl: VHOST_SET_VRING_CALL > + Initiator: Master > Master payload: u64 > > Set the event file descriptor to signal when buffers are used. It > @@ -428,6 +450,7 @@ Message types > > Id: 14 > Equivalent ioctl: VHOST_SET_VRING_ERR > + Initiator: Master > Master payload: u64 > > Set the event file descriptor to signal when error occurs. It > @@ -440,6 +463,7 @@ Message types > > Id: 17 > Equivalent ioctl: N/A > + Initiator: Master > Master payload: N/A > Slave payload: u64 > > @@ -451,6 +475,7 @@ Message types > > Id: 18 > Equivalent ioctl: N/A > + Initiator: Master > Master payload: vring state description > > Signal slave to enable or disable corresponding vring. > @@ -461,6 +486,7 @@ Message types > > Id: 19 > Equivalent ioctl: N/A > + Initiator: Master > Master payload: u64 > > Ask vhost user backend to broadcast a fake RARP to notify the > migration > @@ -475,6 +501,7 @@ Message types > > Id: 20 > Equivalent ioctl: N/A > + Initiator: Master > Master payload: u64 > > Set host MTU value exposed to the guest. > @@ -486,6 +513,17 @@ Message types > If VHOST_USER_PROTOCOL_F_REPLY_ACK is negotiated, slave must respo= nd > with zero in case the specified MTU is valid, or non-zero otherwis= e. > > + * VHOST_USER_SET_SLAVE_REQ_FD > + > + Id: 21 > + Equivalent ioctl: N/A > + Initiator: Master > + > + Set the socket file descriptor for slave initiated requests. > + This request should be sent only when VHOST_USER_F_PROTOCOL_FEATUR= ES > + has been negotiated, and protocol feature bit > VHOST_USER_PROTOCOL_F_SLAVE_REQ > + bit is present in VHOST_USER_GET_PROTOCOL_FEATURES. > + > looks good to me > VHOST_USER_PROTOCOL_F_REPLY_ACK: > ------------------------------- > The original vhost-user specification only demands replies for certain > -- > 2.9.3 > > > -- Marc-Andr=C3=A9 Lureau