Re: [PATCH v2 2/3] libxl: Allow Phy backend for CDROM devices

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

On Thu, Feb 01, 2024 at 04:40:03PM -0500, Jason Andryuk wrote:
> A Linux HVM domain ignores PV block devices with type cdrom.  The
> Windows PV drivers also ignore device-type != "disk".  Therefore QEMU's
> emulated CD-ROM support is used.  This allows ejection and other CD-ROM
> features to work.
> 
> With a stubdom, QEMU is running in the stubdom.  A PV disk is still
> connected into the stubdom, and then QEMU can emulate the CD-ROM into
> the guest.  Phy support has been enhanced to provide a placeholder file
> forempty disks, so it is usable as a CDROM backend as well.  Allow Phy
> to pass the check as well.
> 
> (Bypassing just for a linux-based stubdom doesn't work because
> libxl__device_disk_setdefault() gets called early in domain creation
> before xenstore is populated with relevant information for the stubdom
> type.  The build information isn't readily available and won't exist in
> some call trees, so it isn't usable either.)
> 
> Let disk_try_backend() allow format empty for Phy cdrom drives.
> 
> Signed-off-by: Jason Andryuk <jandryuk@xxxxxxxxx>

Reviewed-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>

Thanks,

-- 
Anthony PERARD