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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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42
tests/vhost-user-bridge.c
View file

@ -45,6 +45,10 @@
} \
} while (0)
enum {
VHOST_USER_BRIDGE_MAX_QUEUES = 8,
};
typedef void (*CallbackFunc)(int sock, void *ctx);
typedef struct Event {
@ -512,12 +516,16 @@ vubr_accept_cb(int sock, void *ctx)
}
DPRINT("Got connection from remote peer on sock %d\n", conn_fd);
vu_init(&dev->vudev,
conn_fd,
vubr_panic,
vubr_set_watch,
vubr_remove_watch,
&vuiface);
if (!vu_init(&dev->vudev,
VHOST_USER_BRIDGE_MAX_QUEUES,
conn_fd,
vubr_panic,
vubr_set_watch,
vubr_remove_watch,
&vuiface)) {
fprintf(stderr, "Failed to initialize libvhost-user\n");
exit(1);
}
dispatcher_add(&dev->dispatcher, conn_fd, ctx, vubr_receive_cb);
dispatcher_remove(&dev->dispatcher, sock);
@ -560,12 +568,18 @@ vubr_new(const char *path, bool client)
if (connect(dev->sock, (struct sockaddr *)&un, len) == -1) {
vubr_die("connect");
}
vu_init(&dev->vudev,
dev->sock,
vubr_panic,
vubr_set_watch,
vubr_remove_watch,
&vuiface);
if (!vu_init(&dev->vudev,
VHOST_USER_BRIDGE_MAX_QUEUES,
dev->sock,
vubr_panic,
vubr_set_watch,
vubr_remove_watch,
&vuiface)) {
fprintf(stderr, "Failed to initialize libvhost-user\n");
exit(1);
}
cb = vubr_receive_cb;
}
@ -584,7 +598,7 @@ static void *notifier_thread(void *arg)
int qidx;
while (true) {
for (qidx = 0; qidx < VHOST_MAX_NR_VIRTQUEUE; qidx++) {
for (qidx = 0; qidx < VHOST_USER_BRIDGE_MAX_QUEUES; qidx++) {
uint16_t *n = vubr->notifier.addr + pagesize * qidx;
if (*n == qidx) {
@ -616,7 +630,7 @@ vubr_host_notifier_setup(VubrDev *dev)
void *addr;
int fd;
length = getpagesize() * VHOST_MAX_NR_VIRTQUEUE;
length = getpagesize() * VHOST_USER_BRIDGE_MAX_QUEUES;
fd = mkstemp(template);
if (fd < 0) {