From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55347) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d8nHn-0002jx-G7 for qemu-devel@nongnu.org; Thu, 11 May 2017 08:33:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d8nHm-0004wu-5X for qemu-devel@nongnu.org; Thu, 11 May 2017 08:33:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53034) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1d8nHl-0004wR-T2 for qemu-devel@nongnu.org; Thu, 11 May 2017 08:33:38 -0400 From: Maxime Coquelin Date: Thu, 11 May 2017 14:32:45 +0200 Message-Id: <20170511123246.31308-6-maxime.coquelin@redhat.com> In-Reply-To: <20170511123246.31308-1-maxime.coquelin@redhat.com> References: <20170511123246.31308-1-maxime.coquelin@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH 5/6] vhost-user: add slave-req-fd support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: mst@redhat.com, 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 Cc: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Maxime Coquelin From: Marc-Andr=C3=A9 Lureau Learn to give a socket to the slave to let him make requests to the master. Signed-off-by: Marc-Andr=C3=A9 Lureau Signed-off-by: Maxime Coquelin --- docs/specs/vhost-user.txt | 32 +++++++++++- hw/virtio/vhost-user.c | 127 ++++++++++++++++++++++++++++++++++++++++= ++++++ 2 files changed, 157 insertions(+), 2 deletions(-) diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt index 036890f..5fa7016 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 =20 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 implemen= ted. @@ -252,6 +253,18 @@ Once the source has finished migration, rings will b= e stopped by the source. No further update must be done before rings are restarted. =20 +Slave communication +------------------- + +An optional communication channel is provided if the slave declares +VHOST_USER_PROTOCOL_F_SLAVE_REQ protocol feature, to allow the slave to = make +requests to the master. + +The fd is provided via VHOST_USER_SET_SLAVE_REQ_FD ancillary data. + +A slave may then send VHOST_USER_SLAVE_* messages to the master +using this fd communication channel. + Protocol features ----------------- =20 @@ -260,9 +273,10 @@ 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 =20 -Message types -------------- +Master message types +-------------------- =20 * VHOST_USER_GET_FEATURES =20 @@ -486,6 +500,20 @@ 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. =20 + * VHOST_USER_SET_SLAVE_REQ_FD + + Id: 21 + Equivalent ioctl: N/A + Master payload: N/A + + Set the socket file descriptor for slave initiated requests. It is= passed + in the ancillary data. + 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. + If VHOST_USER_PROTOCOL_F_REPLY_ACK is negotiated, slave must respo= nd + with zero for success, non-zero otherwise. + VHOST_USER_PROTOCOL_F_REPLY_ACK: ------------------------------- The original vhost-user specification only demands replies for certain diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index f0e10d0..fbc09fa 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -33,6 +33,7 @@ enum VhostUserProtocolFeature { VHOST_USER_PROTOCOL_F_RARP =3D 2, VHOST_USER_PROTOCOL_F_REPLY_ACK =3D 3, VHOST_USER_PROTOCOL_F_NET_MTU =3D 4, + VHOST_USER_PROTOCOL_F_SLAVE_REQ =3D 5, =20 VHOST_USER_PROTOCOL_F_MAX }; @@ -61,9 +62,15 @@ typedef enum VhostUserRequest { VHOST_USER_SET_VRING_ENABLE =3D 18, VHOST_USER_SEND_RARP =3D 19, VHOST_USER_NET_SET_MTU =3D 20, + VHOST_USER_SET_SLAVE_REQ_FD =3D 21, VHOST_USER_MAX } VhostUserRequest; =20 +typedef enum VhostUserSlaveRequest { + VHOST_USER_SLAVE_NONE =3D 0, + VHOST_USER_SLAVE_MAX +} VhostUserSlaveRequest; + typedef struct VhostUserMemoryRegion { uint64_t guest_phys_addr; uint64_t memory_size; @@ -113,6 +120,7 @@ static VhostUserMsg m __attribute__ ((unused)); =20 struct vhost_user { CharBackend *chr; + int slave_fd; }; =20 static bool ioeventfd_enabled(void) @@ -574,6 +582,115 @@ static int vhost_user_reset_device(struct vhost_dev= *dev) return 0; } =20 +static void slave_read(void *opaque) +{ + struct vhost_dev *dev =3D opaque; + struct vhost_user *u =3D dev->opaque; + VhostUserMsg msg =3D { 0, }; + int size, ret =3D 0; + + /* Read header */ + size =3D read(u->slave_fd, &msg, VHOST_USER_HDR_SIZE); + if (size !=3D VHOST_USER_HDR_SIZE) { + error_report("Failed to read from slave."); + goto err; + } + + if (msg.size > VHOST_USER_PAYLOAD_SIZE) { + error_report("Failed to read msg header." + " Size %d exceeds the maximum %zu.", msg.size, + VHOST_USER_PAYLOAD_SIZE); + goto err; + } + + /* Read payload */ + size =3D read(u->slave_fd, &msg.payload, msg.size); + if (size !=3D msg.size) { + error_report("Failed to read payload from slave."); + goto err; + } + + switch (msg.request) { + default: + error_report("Received unexpected msg type."); + ret =3D -EINVAL; + } + + /* + * REPLY_ACK feature handling. Other reply types has to be managed + * directly in their request handlers. + */ + if (msg.flags & VHOST_USER_NEED_REPLY_MASK) { + msg.flags &=3D ~VHOST_USER_NEED_REPLY_MASK; + msg.flags |=3D VHOST_USER_REPLY_MASK; + + msg.payload.u64 =3D !!ret; + msg.size =3D sizeof(msg.payload.u64); + + size =3D write(u->slave_fd, &msg, VHOST_USER_HDR_SIZE + msg.size= ); + if (size !=3D VHOST_USER_HDR_SIZE + msg.size) { + error_report("Failed to send msg reply to slave."); + goto err; + } + } + + return; + +err: + qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL); + close(u->slave_fd); + u->slave_fd =3D -1; + return; +} + +static int vhost_setup_slave_channel(struct vhost_dev *dev) +{ + VhostUserMsg msg =3D { + .request =3D VHOST_USER_SET_SLAVE_REQ_FD, + .flags =3D VHOST_USER_VERSION, + }; + struct vhost_user *u =3D dev->opaque; + int sv[2], ret =3D 0; + bool reply_supported =3D virtio_has_feature(dev->protocol_features, + VHOST_USER_PROTOCOL_F_REPL= Y_ACK); + + if (!virtio_has_feature(dev->protocol_features, + VHOST_USER_PROTOCOL_F_SLAVE_REQ)) { + return 0; + } + + if (socketpair(PF_UNIX, SOCK_STREAM, 0, sv) =3D=3D -1) { + error_report("socketpair() failed"); + return -1; + } + + u->slave_fd =3D sv[0]; + qemu_set_fd_handler(u->slave_fd, slave_read, NULL, dev); + + if (reply_supported) { + msg.flags |=3D VHOST_USER_NEED_REPLY_MASK; + } + + ret =3D vhost_user_write(dev, &msg, &sv[1], 1); + if (ret) { + goto out; + } + + if (reply_supported) { + ret =3D process_message_reply(dev, msg.request); + } + +out: + close(sv[1]); + if (ret) { + qemu_set_fd_handler(u->slave_fd, NULL, NULL, NULL); + close(u->slave_fd); + u->slave_fd =3D -1; + } + + return ret; +} + static int vhost_user_init(struct vhost_dev *dev, void *opaque) { uint64_t features; @@ -584,6 +701,7 @@ static int vhost_user_init(struct vhost_dev *dev, voi= d *opaque) =20 u =3D g_new0(struct vhost_user, 1); u->chr =3D opaque; + u->slave_fd =3D -1; dev->opaque =3D u; =20 err =3D vhost_user_get_features(dev, &features); @@ -624,6 +742,11 @@ static int vhost_user_init(struct vhost_dev *dev, vo= id *opaque) "VHOST_USER_PROTOCOL_F_LOG_SHMFD feature."); } =20 + err =3D vhost_setup_slave_channel(dev); + if (err < 0) { + return err; + } + return 0; } =20 @@ -634,6 +757,10 @@ static int vhost_user_cleanup(struct vhost_dev *dev) assert(dev->vhost_ops->backend_type =3D=3D VHOST_BACKEND_TYPE_USER); =20 u =3D dev->opaque; + if (u->slave_fd >=3D 0) { + close(u->slave_fd); + u->slave_fd =3D -1; + } g_free(u); dev->opaque =3D 0; =20 --=20 2.9.3