Re: [HVM} xen_platform_pci=0 doesn't prevent platform device creation and disk and nic take over by PV drivers.

[Sander Eikelenboom <linux@eikelenboom.it>]

Wednesday, October 9, 2013, 2:00:02 PM, you wrote:

> create ^
> title it xen_platform_pci=0 doesn't work with qemu-xen
> owner it Anthony Perard <anthony.perard@citrix.com>
> thanks

Perhaps in general looking at the libxl and xend .. and .. qemu-xen and qemu-xen-traditonal compatibility shoud be added too.

Perhaps i'm a bit blunt ..
but for users it's quite a mess and PITA now for quite some time, the transition of both is now smeared out over quite some major and minor releases.

With some features not working since .. some features are working again but have a gap of not working,
since old features becoming usable again are (understandably) not backported.

This seems to be at a level that it is even undocumentable ... you would need a spreadsheet
with every minor version to try to document that ... it seems to be leading to a lot of user questions as well.

I'm not blaming any one personally or anything like that .. just expressing my worries and the threat i see for Xen as a project in general.
Namely users sop

I understand that new features like the arm port are interesting .. but i think that has the cost of both
IanC and Stefano time to work on libxl and qemu-upstream seems to be quite limited, and perhaps developer time in general is.

But getting these major transitions smeared out over several major and minor releases doesn't seem to be very desirable.
This will be enlarged since distro's like debian are going to stop packaging the xen-forks. But since they will be using a "stable" release for these
projects like qemu, i will take some time for xen patches to for instance qemu to trickle down into the qemu-upstream stable.

(BTW debian unstable already seems to be not packaging qemu-traditional anymore but rely on the upstream qemu package entirely,
leading to questions on IRC already )

KVM seems to have it's act quite together with their virtio drivers at the moment and i must say i'm getting
attracted to try to switch (although i generally like Xen so i'm still in denial :-) ).

Just my few cents and a call out as a user ..
(and perhaps a topic for the developer conference to address .. also in the light of the short discussion about a long term stable release
which in my opinion can't be done before both are resolved)

Don't know how Pasi thinks about this and if he has any comments, since he seems to be quite involved in (helping) the user community ..

--
Sander



> On Wed, 2013-10-09 at 00:09 +0200, Sander Eikelenboom wrote:
>> Hi,
>> 
>> While trying to get to the bottom of my passthrough problem with the rom bar,
>> i noticed that specifiying "xen_platform_pci=0" in the config file does not prevent
>> the platform device to appear in my HVM guest and consequently the disk and nic are taken over.
>> 
>> Running latest xen-unstable, together with upstream qemu and upstream seabios.
>> 
>> --
>> 
>> Sander
>>