Re: [Qemu-devel] [PATCH v3 5/5] qga: return disk device in guest-get-fsinfo

[Tomáš Golembiovský]

On Thu, 27 Sep 2018 13:06:05 +0400
Marc-André Lureau <address@hidden> wrote:

> Hi
> 
> On Fri, Sep 7, 2018 at 3:42 PM Tomáš Golembiovský <address@hidden> wrote:
> >
> > Report device node of the disk. It is implemented for Linux (needs udev)
> > and Windows. The node is reported e.g. as "/dev/sda2" on Linux and as
> > "\\?\PhysicalDriveX" on Windows.
> >
> > As part of this effort the Windows code was changed to probe disk
> > extents and return list of all disks. Originally only first disk of
> > composite volume was returned.
> >
> > Note that the patch changes get_pci_info() from one state of brokenness
> > into a different state of brokenness. In other words it still does not do
> > what it's supposed to do (see comment in code). If anyone knows how to
> > fix it, please step in.
> >
> > Signed-off-by: Tomáš Golembiovský <address@hidden>  
> 
> ack the schema and udev part.
> 
> What's the use-case behind those extra information fields? It there a
> QGA command that requires disk device node as argument for ex?

We use that to find out how the disks attached to VM map to internal
names inside the guest. This information is not something you can
predict and requires assistance from the running guest OS. What we do is
we assign unique serial numbers to disks and query the mapping from the
guest.

    Tomas