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>
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

View file

@ -19,6 +19,10 @@
#define VUS_ISCSI_INITIATOR "iqn.2016-11.com.nutanix:vhost-user-scsi"
enum {
VHOST_USER_SCSI_MAX_QUEUES = 8,
};
typedef struct VusIscsiLun {
struct iscsi_context *iscsi_ctx;
int iscsi_lun;
@ -231,11 +235,6 @@ static void vus_proc_req(VuDev *vu_dev, int idx)
gdev = container_of(vu_dev, VugDev, parent);
vdev_scsi = container_of(gdev, VusDev, parent);
if (idx < 0 || idx >= VHOST_MAX_NR_VIRTQUEUE) {
g_warning("VQ Index out of range: %d", idx);
vus_panic_cb(vu_dev, NULL);
return;
}
vq = vu_get_queue(vu_dev, idx);
if (!vq) {
@ -295,12 +294,6 @@ static void vus_queue_set_started(VuDev *vu_dev, int idx, bool started)
assert(vu_dev);
if (idx < 0 || idx >= VHOST_MAX_NR_VIRTQUEUE) {
g_warning("VQ Index out of range: %d", idx);
vus_panic_cb(vu_dev, NULL);
return;
}
vq = vu_get_queue(vu_dev, idx);
if (idx == 0 || idx == 1) {
@ -398,7 +391,11 @@ int main(int argc, char **argv)
goto err;
}
vug_init(&vdev_scsi->parent, csock, vus_panic_cb, &vus_iface);
if (!vug_init(&vdev_scsi->parent, VHOST_USER_SCSI_MAX_QUEUES, csock,
vus_panic_cb, &vus_iface)) {
g_printerr("Failed to initialize libvhost-user-glib\n");
goto err;
}
g_main_loop_run(vdev_scsi->loop);