qemu/contrib/libvhost-user/libvhost-user-glib.h
Stefan Hajnoczi 6f5fd83788 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>
2019-07-04 17:00:32 -04:00

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/*
* Vhost User library
*
* Copyright (c) 2016 Nutanix Inc. All rights reserved.
* Copyright (c) 2017 Red Hat, Inc.
*
* Authors:
* Marc-André Lureau <mlureau@redhat.com>
* Felipe Franciosi <felipe@nutanix.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* later. See the COPYING file in the top-level directory.
*/
#ifndef LIBVHOST_USER_GLIB_H
#define LIBVHOST_USER_GLIB_H
#include <glib.h>
#include "libvhost-user.h"
typedef struct VugDev {
VuDev parent;
GHashTable *fdmap; /* fd -> gsource */
GSource *src;
} VugDev;
bool vug_init(VugDev *dev, uint16_t max_queues, int socket,
vu_panic_cb panic, const VuDevIface *iface);
void vug_deinit(VugDev *dev);
GSource *vug_source_new(VugDev *dev, int fd, GIOCondition cond,
vu_watch_cb vu_cb, gpointer data);
#endif /* LIBVHOST_USER_GLIB_H */