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libvhost-user: support many virtqueues

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Currently libvhost-user is hardcoded to at most 8 virtqueues.  The
device backend should decide the number of virtqueues, not
libvhost-user.  This is important for multiqueue device backends where
the guest driver needs an accurate number of virtqueues.

This change breaks libvhost-user and libvhost-user-glib API stability.
There is no stability guarantee yet, so make this change now and update
all in-tree library users.

This patch touches up vhost-user-blk, vhost-user-gpu, vhost-user-input,
vhost-user-scsi, and vhost-user-bridge.  If the device has a fixed
number of queues that exact number is used.  Otherwise the previous
default of 8 virtqueues is used.

vu_init() and vug_init() can now fail if malloc() returns NULL.  I
considered aborting with an error in libvhost-user but it should be safe
to instantiate new vhost-user instances at runtime without risk of
terminating the process.  Therefore callers need to handle the vu_init()
failure now.

vhost-user-blk and vhost-user-scsi duplicate virtqueue index checks that
are already performed by libvhost-user.  This code would need to be
modified to use max_queues but remove it completely instead since it's
redundant.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20190626074815.19994-3-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2019-06-26 08:48:13 +01:00 • committed by Michael S. Tsirkin
parent db68f4ff06
commit 6f5fd83788
9 changed files with 105 additions and 51 deletions
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33
contrib/libvhost-user/libvhost-user.c
View file

@ -493,9 +493,9 @@ vu_get_features_exec(VuDev *dev, VhostUserMsg *vmsg)
static void
vu_set_enable_all_rings(VuDev *dev, bool enabled)
{
int i;
uint16_t i;
for (i = 0; i < VHOST_MAX_NR_VIRTQUEUE; i++) {
for (i = 0; i < dev->max_queues; i++) {
dev->vq[i].enable = enabled;
}
}
@ -916,7 +916,7 @@ vu_check_queue_msg_file(VuDev *dev, VhostUserMsg *vmsg)
{
int index = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;
if (index >= VHOST_MAX_NR_VIRTQUEUE) {
if (index >= dev->max_queues) {
vmsg_close_fds(vmsg);
vu_panic(dev, "Invalid queue index: %u", index);
return false;
@ -1213,7 +1213,7 @@ vu_set_vring_enable_exec(VuDev *dev, VhostUserMsg *vmsg)
DPRINT("State.index: %d\n", index);
DPRINT("State.enable: %d\n", enable);
if (index >= VHOST_MAX_NR_VIRTQUEUE) {
if (index >= dev->max_queues) {
vu_panic(dev, "Invalid vring_enable index: %u", index);
return false;
}
@ -1582,7 +1582,7 @@ vu_deinit(VuDev *dev)
}
dev->nregions = 0;
for (i = 0; i < VHOST_MAX_NR_VIRTQUEUE; i++) {
for (i = 0; i < dev->max_queues; i++) {
VuVirtq *vq = &dev->vq[i];
if (vq->call_fd != -1) {
@ -1627,18 +1627,23 @@ vu_deinit(VuDev *dev)
if (dev->sock != -1) {
close(dev->sock);
}
free(dev->vq);
dev->vq = NULL;
}
void
bool
vu_init(VuDev *dev,
uint16_t max_queues,
int socket,
vu_panic_cb panic,
vu_set_watch_cb set_watch,
vu_remove_watch_cb remove_watch,
const VuDevIface *iface)
{
int i;
uint16_t i;
assert(max_queues > 0);
assert(socket >= 0);
assert(set_watch);
assert(remove_watch);
@ -1654,18 +1659,28 @@ vu_init(VuDev *dev,
dev->iface = iface;
dev->log_call_fd = -1;
dev->slave_fd = -1;
for (i = 0; i < VHOST_MAX_NR_VIRTQUEUE; i++) {
dev->max_queues = max_queues;
dev->vq = malloc(max_queues * sizeof(dev->vq[0]));
if (!dev->vq) {
DPRINT("%s: failed to malloc virtqueues\n", __func__);
return false;
}
for (i = 0; i < max_queues; i++) {
dev->vq[i] = (VuVirtq) {
.call_fd = -1, .kick_fd = -1, .err_fd = -1,
.notification = true,
};
}
return true;
}
VuVirtq *
vu_get_queue(VuDev *dev, int qidx)
{
assert(qidx < VHOST_MAX_NR_VIRTQUEUE);
assert(qidx < dev->max_queues);
return &dev->vq[qidx];
}