Re: [libvirt] [PATCH V4 3/3] Add support for file descriptor sets

Add support for file descriptor sets by converting some of the command line parameters to use /dev/fdset/%d if -add-fd is found to be supported by QEMU. For those devices libvirt now open()s the device to obtain the file descriptor and 'transfers' the fd using virCommand. For the following fragments of domain XML <disk type='file' device='disk'> <driver name='qemu' type='raw'/> <source file='/var/lib/libvirt/images/fc14-x86_64.img'/> <target dev='hda' bus='ide'/> <address type='drive' controller='0' bus='0' target='0' unit='0'/> </disk> <serial type='dev'> <source path='/dev/ttyS0'/> <target port='0'/> </serial> <serial type='pipe'> <source path='/tmp/testpipe'/> <target port='1'/> </serial> libvirt now creates the following parts for the QEMU command line: old: -drive file=/var/lib/libvirt/images/fc14-x86_64.img,if=none,id=drive-ide0-0-0,format=raw new: -add-fd set=1,fd=23,opaque=RDONLY:/var/lib/libvirt/images/fc14-x86_64.img -add-fd set=1,fd=24,opaque=RDWR:/var/lib/libvirt/images/fc14-x86_64.img -drive file=/dev/fdset/1,if=none,id=drive-ide0-0-0,format=raw old: -chardev tty,id=charserial0,path=/dev/ttyS0 new: -add-fd set=1,fd=30,opaque=/dev/ttyS0 -chardev tty,id=charserial0,path=/dev/fdset/1 old: -chardev pipe,id=charserial1,path=/tmp/testpipe new: -add-fd set=2,fd=32,opaque=/tmp/testpipe -chardev pipe,id=charserial1,path=/dev/fdset/2 Test cases are part of this patch now. Signed-off-by: Stefan Berger <stefanb(a)linux.vnet.ibm.com&gt;

@@ -201,6 +206,7 @@ out: virCommandFree(cmd); virDomainDefFree(vmdef); virObjectUnref(conn); + virFdsetClear(&fdset); return ret; } @@ -875,6 +881,11 @@ mymain(void) QEMU_CAPS_DEVICE, QEMU_CAPS_DEVICE_VIDEO_PRIMARY, QEMU_CAPS_DEVICE_QXL, QEMU_CAPS_DEVICE_QXL_VGA); + DO_TEST("no-add-fd", + QEMU_CAPS_CHARDEV, QEMU_CAPS_DEVICE, QEMU_CAPS_DRIVE);

+ DO_TEST("add-fd", QEMU_CAPS_ADD_FD, + QEMU_CAPS_CHARDEV, QEMU_CAPS_DEVICE, QEMU_CAPS_DRIVE);