On Wed, 27 Mar 2019 16:22:33 +0200 "П, Алексей" <[email protected]> wrote:
> Please excuse any errors on my part and for my insistense, i had closed my > research in case of "handle" backend, the last case which i cannot resolve > is to find purpose of "synthetic 9p file system". I'm stuck in testing with > command below: > > > > qemu-system-x86_64 -cpu max \ > -accel kvm \ > -m size=512M \ > -blockdev driver=file,node-name=hdd,filename=debian.img \ > -device driver=ide-hd,drive=hdd \ > -virtfs_synth > > I mean i cannot find any example of using command mentioned above. > > Please provide me If there are any material to study. > > Thanks. The original purpose of the synth backend is best explained in the changelog of the patch that introduced it: commit 9db221ae73a18e0bd2b1ee6c7dc1904ed06fb464 Author: Aneesh Kumar K.V <[email protected]> Date: Tue Oct 25 12:10:40 2011 +0530 hw/9pfs: Add synthetic file system support using 9p This patch create a synthetic file system with mount tag v_synth when -virtfs_synth command line option is specified in qemu. The synthetic file system can be mounted in guest using 9p using the below command line mount -t 9p -oversion=9p2000.L,trans=virtio v_synth <mountpint> Synthetic file system enabled different qemu subsystem to register callbacks for read and write events from guest. The subsystem can create directories and files in the synthetic file system as show in ex below qemu_v9fs_synth_mkdir(NULL, 0777, "test2", &node); qemu_v9fs_synth_add_file(node, 0777, "testfile", my_test_read, NULL, NULL); Signed-off-by: Aneesh Kumar K.V <[email protected]> This never took momentum really and no QEMU subsystem ever registered anything. I finally found some use for it in order to test the core 9p code with qtest (see 2893ddd5988a3). Cheers, -- Greg
