[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Multiple platform PCI device ID registries?
On Wed, 2013-11-13 at 12:50 +0000, Paul Durrant wrote: > > -----Original Message----- > > From: Ian Campbell > > Sent: 13 November 2013 12:39 > > To: Paul Durrant > > Cc: xen-devel; Ian Jackson; Stefano Stabellini > > Subject: Re: Multiple platform PCI device ID registries? > > > > On Wed, 2013-11-13 at 12:30 +0000, Paul Durrant wrote: > > > > -----Original Message----- > > > > From: Ian Campbell > > > > Sent: 13 November 2013 12:09 > > > > To: Paul Durrant > > > > Cc: xen-devel; Ian Jackson; Stefano Stabellini > > > > Subject: Re: Multiple platform PCI device ID registries? > > > > > > > > On Wed, 2013-11-13 at 11:58 +0000, Paul Durrant wrote: > > > > > > > > > > I'm concerned because that comment refers to XenServer 6.1 but it > > now > > > > > > appears to be being reused as the default device ID for the "Xen > > > > > > pvdevice". > > > > > > > > > > > > Maybe it is safe to reuse this in this way, but the docs should be > > > > > > updated I think. > > > > > > > > > > > > > > > > I believe it is safe. > > > > > > > > How would you describe it in that document? "Xen PV device (extended > > > > platform device). Previously used in XenServer 6.1" ? > > > > > > > > Is there some spec we can link to regarding how this device should be > > > > used? > > > > ??? > > Sorry, missed that. You've missed the part about a link to a spec for what the Xen PV device is, when it should appear, how it relates to the platform device again > No, it wasn't previously used in 6.1 because it's not really the same > (as the pv device doesn't implement the fixed IO ports). I also don't > want to confuse it with the platform device, for that reason. It is a > new distinct and I agree that the fact it defaults to device ID is > confusing although it's safe - I will therefore submit a patch to QEMU > to modify it as I suggested before, so that the id *must* be specified > by the toolstack. Ack. > > > > Best bet is to just document "Don't Do That Then". Is there some > > XenServer way we can tell people to fix this (by changing the ID back?) > > > > Well part of the problem is that we don't support use of PVonHVM linux > in XenServer at all! The best thing is probably to tackle this on the > XenServer forums if and when someone posts the problem there. Adding > the extra blacklisting code to XenServer's QEMU and then getting that > into a hotfix should hopefully avoid future problems too - although we > may get 'why are my PV frontends not working?'-type questions. Ah, I see now why it is a XS side fix. > > I think "no platform device and no pv device" is a valid and useful > > configuration, meaning "use emulated devices". "no platform device, yes > > pv device" is the one to avoid. > > > > Hmm. How about splitting out the fixed IO ports then? That way the > platform device could be safely turned off if the PV device was > present. It seems like a cleaner and safer thing to do. I thought when the PV device was added it was agreed that it would only ever be as an extension to the platform device, not a replacement for it. Otherwise you get into situations where cloud providers need to know which to provide, whereas with a baseline platform device always there things can try and work. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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