qemu-e2k/hw/virtio/vhost-backend.c
Nikolay Nikolaev 5f6f6664bf Add vhost-user as a vhost backend.
The initialization takes a chardev backed by a unix domain socket.
It should implement qemu_fe_set_msgfds in order to be able to pass
file descriptors to the remote process.

Each ioctl request of vhost-kernel has a vhost-user message equivalent,
which is sent over the control socket.

The general approach is to copy the data from the supplied argument
pointer to a designated field in the message. If a file descriptor is
to be passed it will be placed in the fds array for inclusion in
the sendmsg control header.

VHOST_SET_MEM_TABLE ignores the supplied vhost_memory structure and scans
the global ram_list for ram blocks with a valid fd field set. This would
be set when the '-object memory-file' option with share=on property is used.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-06-19 16:41:56 +03:00

72 lines
1.6 KiB
C

/*
* vhost-backend
*
* Copyright (c) 2013 Virtual Open Systems Sarl.
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#include "hw/virtio/vhost.h"
#include "hw/virtio/vhost-backend.h"
#include "qemu/error-report.h"
#include <sys/ioctl.h>
extern const VhostOps user_ops;
static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request,
void *arg)
{
int fd = (uintptr_t) dev->opaque;
assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
return ioctl(fd, request, arg);
}
static int vhost_kernel_init(struct vhost_dev *dev, void *opaque)
{
assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
dev->opaque = opaque;
return 0;
}
static int vhost_kernel_cleanup(struct vhost_dev *dev)
{
int fd = (uintptr_t) dev->opaque;
assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_KERNEL);
return close(fd);
}
static const VhostOps kernel_ops = {
.backend_type = VHOST_BACKEND_TYPE_KERNEL,
.vhost_call = vhost_kernel_call,
.vhost_backend_init = vhost_kernel_init,
.vhost_backend_cleanup = vhost_kernel_cleanup
};
int vhost_set_backend_type(struct vhost_dev *dev, VhostBackendType backend_type)
{
int r = 0;
switch (backend_type) {
case VHOST_BACKEND_TYPE_KERNEL:
dev->vhost_ops = &kernel_ops;
break;
case VHOST_BACKEND_TYPE_USER:
dev->vhost_ops = &user_ops;
break;
default:
error_report("Unknown vhost backend type\n");
r = -1;
}
return r;
}