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[PULL v2 27/30] libvhost-user: implement in-band notifications
From: |
Michael S. Tsirkin |
Subject: |
[PULL v2 27/30] libvhost-user: implement in-band notifications |
Date: |
Wed, 26 Feb 2020 04:07:48 -0500 |
From: Johannes Berg <address@hidden>
Add support for VHOST_USER_PROTOCOL_F_IN_BAND_NOTIFICATIONS, but
as it's not desired by default, don't enable it unless the device
implementation opts in by returning it from its protocol features
callback.
Note that I updated vu_set_vring_err_exec(), but didn't add any
sending of the VHOST_USER_SLAVE_VRING_ERR message as there's no
write to the err_fd today either.
This also adds vu_queue_notify_sync() which can be used to force
a synchronous notification if inband notifications are supported.
Previously, I had left out the slave->master direction handling
of F_REPLY_ACK, this now adds some code to support it as well.
Signed-off-by: Johannes Berg <address@hidden>
Message-Id: <address@hidden>
Reviewed-by: Michael S. Tsirkin <address@hidden>
Signed-off-by: Michael S. Tsirkin <address@hidden>
---
contrib/libvhost-user/libvhost-user.h | 14 ++++
contrib/libvhost-user/libvhost-user.c | 103 +++++++++++++++++++++++++-
2 files changed, 114 insertions(+), 3 deletions(-)
diff --git a/contrib/libvhost-user/libvhost-user.h
b/contrib/libvhost-user/libvhost-user.h
index 5cb7708559..6fc8000e99 100644
--- a/contrib/libvhost-user/libvhost-user.h
+++ b/contrib/libvhost-user/libvhost-user.h
@@ -54,6 +54,7 @@ enum VhostUserProtocolFeature {
VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD = 10,
VHOST_USER_PROTOCOL_F_HOST_NOTIFIER = 11,
VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD = 12,
+ VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS = 14,
VHOST_USER_PROTOCOL_F_MAX
};
@@ -95,6 +96,7 @@ typedef enum VhostUserRequest {
VHOST_USER_GET_INFLIGHT_FD = 31,
VHOST_USER_SET_INFLIGHT_FD = 32,
VHOST_USER_GPU_SET_SOCKET = 33,
+ VHOST_USER_VRING_KICK = 35,
VHOST_USER_MAX
} VhostUserRequest;
@@ -103,6 +105,8 @@ typedef enum VhostUserSlaveRequest {
VHOST_USER_SLAVE_IOTLB_MSG = 1,
VHOST_USER_SLAVE_CONFIG_CHANGE_MSG = 2,
VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG = 3,
+ VHOST_USER_SLAVE_VRING_CALL = 4,
+ VHOST_USER_SLAVE_VRING_ERR = 5,
VHOST_USER_SLAVE_MAX
} VhostUserSlaveRequest;
@@ -528,6 +532,16 @@ bool vu_queue_empty(VuDev *dev, VuVirtq *vq);
*/
void vu_queue_notify(VuDev *dev, VuVirtq *vq);
+/**
+ * vu_queue_notify_sync:
+ * @dev: a VuDev context
+ * @vq: a VuVirtq queue
+ *
+ * Request to notify the queue via callfd (skipped if unnecessary)
+ * or sync message if possible.
+ */
+void vu_queue_notify_sync(VuDev *dev, VuVirtq *vq);
+
/**
* vu_queue_pop:
* @dev: a VuDev context
diff --git a/contrib/libvhost-user/libvhost-user.c
b/contrib/libvhost-user/libvhost-user.c
index 3abc9689e5..3bca996c62 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -136,6 +136,7 @@ vu_request_to_string(unsigned int req)
REQ(VHOST_USER_GET_INFLIGHT_FD),
REQ(VHOST_USER_SET_INFLIGHT_FD),
REQ(VHOST_USER_GPU_SET_SOCKET),
+ REQ(VHOST_USER_VRING_KICK),
REQ(VHOST_USER_MAX),
};
#undef REQ
@@ -163,7 +164,10 @@ vu_panic(VuDev *dev, const char *msg, ...)
dev->panic(dev, buf);
free(buf);
- /* FIXME: find a way to call virtio_error? */
+ /*
+ * FIXME:
+ * find a way to call virtio_error, or perhaps close the connection?
+ */
}
/* Translate guest physical address to our virtual address. */
@@ -1203,6 +1207,14 @@ vu_set_vring_err_exec(VuDev *dev, VhostUserMsg *vmsg)
static bool
vu_get_protocol_features_exec(VuDev *dev, VhostUserMsg *vmsg)
{
+ /*
+ * Note that we support, but intentionally do not set,
+ * VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS. This means that
+ * a device implementation can return it in its callback
+ * (get_protocol_features) if it wants to use this for
+ * simulation, but it is otherwise not desirable (if even
+ * implemented by the master.)
+ */
uint64_t features = 1ULL << VHOST_USER_PROTOCOL_F_MQ |
1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD |
1ULL << VHOST_USER_PROTOCOL_F_SLAVE_REQ |
@@ -1235,6 +1247,25 @@ vu_set_protocol_features_exec(VuDev *dev, VhostUserMsg
*vmsg)
dev->protocol_features = vmsg->payload.u64;
+ if (vu_has_protocol_feature(dev,
+ VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS) &&
+ (!vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_SLAVE_REQ) ||
+ !vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_REPLY_ACK))) {
+ /*
+ * The use case for using messages for kick/call is simulation, to make
+ * the kick and call synchronous. To actually get that behaviour, both
+ * of the other features are required.
+ * Theoretically, one could use only kick messages, or do them without
+ * having F_REPLY_ACK, but too many (possibly pending) messages on the
+ * socket will eventually cause the master to hang, to avoid this in
+ * scenarios where not desired enforce that the settings are in a way
+ * that actually enables the simulation case.
+ */
+ vu_panic(dev,
+ "F_IN_BAND_NOTIFICATIONS requires F_SLAVE_REQ &&
F_REPLY_ACK");
+ return false;
+ }
+
if (dev->iface->set_protocol_features) {
dev->iface->set_protocol_features(dev, features);
}
@@ -1495,6 +1526,34 @@ vu_set_inflight_fd(VuDev *dev, VhostUserMsg *vmsg)
return false;
}
+static bool
+vu_handle_vring_kick(VuDev *dev, VhostUserMsg *vmsg)
+{
+ unsigned int index = vmsg->payload.state.index;
+
+ if (index >= dev->max_queues) {
+ vu_panic(dev, "Invalid queue index: %u", index);
+ return false;
+ }
+
+ DPRINT("Got kick message: handler:%p idx:%d\n",
+ dev->vq[index].handler, index);
+
+ if (!dev->vq[index].started) {
+ dev->vq[index].started = true;
+
+ if (dev->iface->queue_set_started) {
+ dev->iface->queue_set_started(dev, index, true);
+ }
+ }
+
+ if (dev->vq[index].handler) {
+ dev->vq[index].handler(dev, index);
+ }
+
+ return false;
+}
+
static bool
vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
{
@@ -1577,6 +1636,8 @@ vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
return vu_get_inflight_fd(dev, vmsg);
case VHOST_USER_SET_INFLIGHT_FD:
return vu_set_inflight_fd(dev, vmsg);
+ case VHOST_USER_VRING_KICK:
+ return vu_handle_vring_kick(dev, vmsg);
default:
vmsg_close_fds(vmsg);
vu_panic(dev, "Unhandled request: %d", vmsg->request);
@@ -2038,8 +2099,7 @@ vring_notify(VuDev *dev, VuVirtq *vq)
return !v || vring_need_event(vring_get_used_event(vq), new, old);
}
-void
-vu_queue_notify(VuDev *dev, VuVirtq *vq)
+static void _vu_queue_notify(VuDev *dev, VuVirtq *vq, bool sync)
{
if (unlikely(dev->broken) ||
unlikely(!vq->vring.avail)) {
@@ -2051,11 +2111,48 @@ vu_queue_notify(VuDev *dev, VuVirtq *vq)
return;
}
+ if (vq->call_fd < 0 &&
+ vu_has_protocol_feature(dev,
+ VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS) &&
+ vu_has_protocol_feature(dev, VHOST_USER_PROTOCOL_F_SLAVE_REQ)) {
+ VhostUserMsg vmsg = {
+ .request = VHOST_USER_SLAVE_VRING_CALL,
+ .flags = VHOST_USER_VERSION,
+ .size = sizeof(vmsg.payload.state),
+ .payload.state = {
+ .index = vq - dev->vq,
+ },
+ };
+ bool ack = sync &&
+ vu_has_protocol_feature(dev,
+ VHOST_USER_PROTOCOL_F_REPLY_ACK);
+
+ if (ack) {
+ vmsg.flags |= VHOST_USER_NEED_REPLY_MASK;
+ }
+
+ vu_message_write(dev, dev->slave_fd, &vmsg);
+ if (ack) {
+ vu_message_read(dev, dev->slave_fd, &vmsg);
+ }
+ return;
+ }
+
if (eventfd_write(vq->call_fd, 1) < 0) {
vu_panic(dev, "Error writing eventfd: %s", strerror(errno));
}
}
+void vu_queue_notify(VuDev *dev, VuVirtq *vq)
+{
+ _vu_queue_notify(dev, vq, false);
+}
+
+void vu_queue_notify_sync(VuDev *dev, VuVirtq *vq)
+{
+ _vu_queue_notify(dev, vq, true);
+}
+
static inline void
vring_used_flags_set_bit(VuVirtq *vq, int mask)
{
--
MST
- [PULL v2 17/30] virtio-iommu: Implement fault reporting, (continued)
- [PULL v2 17/30] virtio-iommu: Implement fault reporting, Michael S. Tsirkin, 2020/02/26
- [PULL v2 18/30] virtio-iommu: Support migration, Michael S. Tsirkin, 2020/02/26
- [PULL v2 19/30] virtio-iommu-pci: Add virtio iommu pci support, Michael S. Tsirkin, 2020/02/26
- [PULL v2 20/30] hw/arm/virt: Add the virtio-iommu device tree mappings, Michael S. Tsirkin, 2020/02/26
- [PULL v2 21/30] MAINTAINERS: add virtio-iommu related files, Michael S. Tsirkin, 2020/02/26
- [PULL v2 22/30] libvhost-user: implement VHOST_USER_PROTOCOL_F_REPLY_ACK, Michael S. Tsirkin, 2020/02/26
- [PULL v2 23/30] libvhost-user-glib: fix VugDev main fd cleanup, Michael S. Tsirkin, 2020/02/26
- [PULL v2 24/30] libvhost-user-glib: use g_main_context_get_thread_default(), Michael S. Tsirkin, 2020/02/26
- [PULL v2 25/30] libvhost-user: handle NOFD flag in call/kick/err better, Michael S. Tsirkin, 2020/02/26
- [PULL v2 26/30] docs: vhost-user: add in-band kick/call messages, Michael S. Tsirkin, 2020/02/26
- [PULL v2 27/30] libvhost-user: implement in-band notifications,
Michael S. Tsirkin <=
- [PULL v2 28/30] acpi: cpuhp: document CPHP_GET_CPU_ID_CMD command, Michael S. Tsirkin, 2020/02/26
- [PULL v2 29/30] vhost-user: only set slave channel for first vq, Michael S. Tsirkin, 2020/02/26
- [PULL v2 30/30] Fixed assert in vhost_user_set_mem_table_postcopy, Michael S. Tsirkin, 2020/02/26
- Re: [PULL v2 00/30] virtio, pc: fixes, features, Michael S. Tsirkin, 2020/02/27