libvhost-user: support many virtqueues
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>
diff --git a/contrib/vhost-user-blk/vhost-user-blk.c b/contrib/vhost-user-blk/vhost-user-blk.c
index 86a3987..ae61034 100644
--- a/contrib/vhost-user-blk/vhost-user-blk.c
+++ b/contrib/vhost-user-blk/vhost-user-blk.c
@@ -25,6 +25,10 @@
#include <sys/ioctl.h>
#endif
+enum {
+ VHOST_USER_BLK_MAX_QUEUES = 8,
+};
+
struct virtio_blk_inhdr {
unsigned char status;
};
@@ -334,12 +338,6 @@
VuVirtq *vq;
int ret;
- if ((idx < 0) || (idx >= VHOST_MAX_NR_VIRTQUEUE)) {
- fprintf(stderr, "VQ Index out of range: %d\n", idx);
- vub_panic_cb(vu_dev, NULL);
- return;
- }
-
gdev = container_of(vu_dev, VugDev, parent);
vdev_blk = container_of(gdev, VubDev, parent);
assert(vdev_blk);
@@ -631,7 +629,11 @@
vdev_blk->enable_ro = true;
}
- vug_init(&vdev_blk->parent, csock, vub_panic_cb, &vub_iface);
+ if (!vug_init(&vdev_blk->parent, VHOST_USER_BLK_MAX_QUEUES, csock,
+ vub_panic_cb, &vub_iface)) {
+ fprintf(stderr, "Failed to initialized libvhost-user-glib\n");
+ goto err;
+ }
g_main_loop_run(vdev_blk->loop);
