Re: [PATCH] libxl: No emulated disk driver for xvdX disk

[Boris Ostrovsky <boris.ostrovsky@oracle.com>]

On 10/27/2015 09:19 AM, Ian Jackson wrote:
> George Dunlap writes ("Re: [Xen-devel] [PATCH] libxl: No emulated disk driver for xvdX disk"):
>> On Tue, Oct 27, 2015 at 11:11 AM, Stefano Stabellini
>> <stefano.stabellini@eu.citrix.com> wrote:
>>> The guest can access xvdX disks via the PV block protocol, or via
>>> UEFI firmare using EFI BootServices.
>> But it introduces a sort of regression in some setups -- namely,
>> before you could use exactly the same disk and config file for either
>> a PV or HVM guest, simply adding builder=hvm (either to the file or
>> the command line) to switch between the two.
> The purpose of the `vdev' in the xl disk specification is to say how
> the disk should be presented to the guest.
>
> Did you look at docs/misc/vbd-interface.txt ?
>
> If you want something that is accessible via the BIOS etc. in HVM
> guests, why not use vdev=hda rather than vdev=xvda ?

Yes, but since we've discovered that people do use xvda (and have been 
doing this for long time --- our test framework has been running for 
many years configured like that) --- do we want this to suddenly break?

-boris