Re: [Qemu-devel] last one question about VirtFS

[П , Алексей]

Thanks!

ср, 27 мар. 2019 г. в 16:41, Greg Kurz <address@hidden>:

> On Wed, 27 Mar 2019 16:22:33 +0200
> "П, Алексей" <address@hidden> 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 <address@hidden>
> 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 <address@hidden>
>
>
> 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
>