Re: [PATCH 20/29] tools: add 9pfs device to xenstore-stubdom

[Juergen Gross <jgross@xxxxxxxx>]

On 07.11.23 20:18, Jason Andryuk wrote:
> On Wed, Nov 1, 2023 at 8:23 AM Juergen Gross <jgross@xxxxxxxx> wrote:
> > Add a 9pfs device to Xenstore stubdom in order to allow it to do e.g.
> > logging into a dom0 file.
> >
> > Use the following parameters for the new device:
> >
> > - tag = "xen"
> > - type = "xenlogd"
> > - path = "/var/lib/xen/xenstore"
> >
> > For now don't limit allowed file space or number of files.
> >
> > Add a new libxl function for adding it similar to the function for
> > adding the console device.
> >
> > Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> > diff --git a/tools/libs/light/libxl_9pfs.c b/tools/libs/light/libxl_9pfs.c
> > index 0b9d84dce9..3297389493 100644
> > --- a/tools/libs/light/libxl_9pfs.c
> > +++ b/tools/libs/light/libxl_9pfs.c
> > @@ -174,6 +174,35 @@ static void libxl__device_p9_add(libxl__egc *egc, uint32_t 
> > domid,
> >           aodev->callback(egc, aodev);
> >   }
> >
> > +int libxl_p9_add_xenstore(libxl_ctx *ctx, uint32_t domid, uint32_t backend,
> > +                          libxl_p9_type type, char *tag, char *path,
> > +                          unsigned int max_space, unsigned int max_files,
> > +                          unsigned int max_open_files, bool auto_delete,
> > +                          const libxl_asyncop_how *ao_how)
> > +{
> > +    AO_CREATE(ctx, domid, ao_how);
> > +    libxl__ao_device *aodev;
> > +    libxl_device_p9 p9 = { .backend_domid = backend,
> > +                           .tag = tag,
> > +                           .path = path,
> > +                           .security_model = "none",
> While the xl.cfg man page states that only security_model="none" is
> supported, it is possible to use other ones.    The value isn't
> inspected and it is just passed through Xenstore to QEMU.  QEMU can
> then operate however it operates.  I just tested mapped-xattr and it's
> working from some quick testing.  So maybe libxl_p9_add_xenstore()
> should take security_model as an argument, and then
> init-xenstore-domain can pass in "none"?
Yes, good idea.

> Everything else looks good, so either way:
> Reviewed-by: Jason Andryuk <jandryuk@xxxxxxxxx>
Thanks,

Juergen

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