This commit introduces a vhost-user-scsi backend sample application. It
must be linked with libiscsi and libvhost-user.
To use it, compile with:
$ make vhost-user-scsi
And run as follows:
$ ./vhost-user-scsi -u vus.sock -i iscsi://uri_to_target/
$ qemu-system-x86_64 --enable-kvm -m 512 \
-object memory-backend-file,id=mem,size=512m,share=on,mem-path=guestmem \
-numa node,memdev=mem \
-chardev socket,id=vhost-user-scsi,path=vus.sock \
-device vhost-user-scsi-pci,chardev=vhost-user-scsi \
The application is currently limited at one LUN only and it processes
requests synchronously (therefore only achieving QD1). The purpose of
the code is to show how a backend can be implemented and to test the
vhost-user-scsi Qemu implementation.
If a different instance of this vhost-user-scsi application is executed
at a remote host, a VM can be live migrated to such a host.
Signed-off-by: Felipe Franciosi <felipe@nutanix.com>
Message-Id: <1488479153-21203-5-git-send-email-felipe@nutanix.com>
Calling libvhost-user functions like vu_queue_get_avail_bytes() when the
queue doesn't yet have addresses will result in the crashes like the
following:
Program received signal SIGSEGV, Segmentation fault.
0x000055c414112ce4 in vring_avail_idx (vq=0x55c41582fd68, vq=0x55c41582fd68)
at /home/dgilbert/git/qemu/contrib/libvhost-user/libvhost-user.c:940
940 vq->shadow_avail_idx = vq->vring.avail->idx;
(gdb) p vq
$1 = (VuVirtq *) 0x55c41582fd68
(gdb) p vq->vring
$2 = {num = 0, desc = 0x0, avail = 0x0, used = 0x0, log_guest_addr = 0, flags = 0}
at /home/dgilbert/git/qemu/contrib/libvhost-user/libvhost-user.c:940
No locals.
at /home/dgilbert/git/qemu/contrib/libvhost-user/libvhost-user.c:960
num_heads = <optimized out>
out_bytes=out_bytes@entry=0x7fffd035d7c4, max_in_bytes=max_in_bytes@entry=0,
max_out_bytes=max_out_bytes@entry=0) at /home/dgilbert/git/qemu/contrib/libvhost-user/libvhost-user.c:1034
Add a pre-condition checks on vring.avail before accessing it.
Fix documentation and return type of vu_queue_empty() while at it.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Tested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
On gcc 3.4 and newer, simply using (void) in front of WUR functions is
not sufficient to ignore the return value. That prevents a build when
handling warnings as errors.
libvhost-user had a usage of (void)vasprintf() which triggered such a
condition. This fixes it by replacing this call with g_strdup_vprintf()
which aborts on OOM.
Signed-off-by: Felipe Franciosi <felipe@nutanix.com>
Message-Id: <1488479153-21203-2-git-send-email-felipe@nutanix.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Add a library to help implementing vhost-user backend (or slave).
Dealing with vhost-user as an application developer isn't so easy: you
have all the trouble with any protocol: validation, unix ancillary data,
shared memory, eventfd, logging, and on top of that you need to deal
with virtio queues, if possible efficiently.
qemu test has a nice vhost-user testing application vhost-user-bridge,
which implements most of vhost-user, and virtio.c which implements
virtqueues manipulation. Based on these two, I tried to make a simple
library, reusable for tests or development of new vhost-user scenarios.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
[Felipe: set used_idx copy on SET_VRING_ADDR and update shadow avail idx
on SET_VRING_BASE]
Signed-off-by: Felipe Franciosi <felipe@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
