[libvirt] [PATCH v2 11/11] qemu: auto-add pci-root controller for pc machine types

[Ján Tomko]

On 04/18/2013 04:38 PM, Laine Stump wrote:
> On 04/18/2013 08:09 AM, Ján Tomko wrote:
>> On 04/18/2013 07:22 AM, Laine Stump wrote:
>>> On 04/17/2013 03:00 PM, Ján Tomko wrote:
>>>> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
>>>> index 68518a7..a2179aa 100644
>>>> --- a/src/conf/domain_conf.c
>>>> +++ b/src/conf/domain_conf.c
>>>> @@ -10849,9 +10849,15 @@ virDomainDefParseXML(xmlDocPtr xml,
>>>>  
>>>>      if (def->virtType == VIR_DOMAIN_VIRT_QEMU ||
>>>>          def->virtType == VIR_DOMAIN_VIRT_KQEMU ||
>>>> -        def->virtType == VIR_DOMAIN_VIRT_KVM)
>>>> +        def->virtType == VIR_DOMAIN_VIRT_KVM) {
>>>>          if (virDomainDefMaybeAddController(def, VIR_DOMAIN_CONTROLLER_TYPE_USB, 0, -1) < 0)
>>>>              goto error;
>>>> +        if (STRPREFIX(def->os.machine,"pc")) {
>>>
>>> You also need to do this for all rhel-* machine types. Even though that
>>> machine type only shows up in RHEL-specific versions of qemu, it is
>>> possible for someone with a stock RHEL qemu to install upstream libvirt,
>>> and we don't want to break that.
>> It seems these are not the only machines with a PCI bus (PPC for example
>> has one), which makes me wonder how many things this will break.
> 
> 
> Well, we're going to need to figure those out. We can either do it for
> all, and let people interested in particular machinetypes explicitly
> exclude theirs, or we can do it only for those machinetypes that we know
> have a PCI bus, and wait for the others to complain; I guess it all
> depends on if we want to minimize pain, or minimize the amount of time
> that passes before we get it right.
> 
> I'm not sure if the presence of "PCI" in the output of qemu-system-*
> -help is an accurate indicator of which platforms have a PCI bus, but I
> tried running that on all the qemu emulators on my Fedora 18 system and
> got the following list of qemu binaries that have devices claiming to
> live on a PCI bus:
> 
> for e in qemu-system-*; do if $e -device \? 2>&1| grep -q PCI; then echo
> "YES - $e"; else echo "NO  - $e"; fi; done
> YES - qemu-system-alpha
> YES - qemu-system-arm
> NO  - qemu-system-cris
> YES - qemu-system-i386
> NO  - qemu-system-lm32
> YES - qemu-system-m68k
> NO  - qemu-system-microblaze
> NO  - qemu-system-microblazeel
> YES - qemu-system-mips
> YES - qemu-system-mips64
> YES - qemu-system-mips64el
> YES - qemu-system-mipsel
> NO  - qemu-system-or32
> YES - qemu-system-ppc
> YES - qemu-system-ppc64
> YES - qemu-system-ppcemb
> NO  - qemu-system-s390x
> YES - qemu-system-sh4
> YES - qemu-system-sh4eb
> NO  - qemu-system-sparc
> YES - qemu-system-sparc64
> NO  - qemu-system-unicore32
> YES - qemu-system-x86_64
> NO  - qemu-system-xtensa
> NO  - qemu-system-xtensaeb
> 
> So within any binary that supports PCI devices, does that necessarily
> mean it's supported for *all* machinetypes? If so, we've got a pretty
> long list of machinetypes to check for:
> 
> ( for e in qemu-system-*; do if $e -device \? 2>&1| grep -q PCI; then $e
> -M ? | cut -f1 -d' ' | grep -v Supported | grep -v none; fi; done ) |
> sort | uniq | wc
>      72      72     590
> 
> (note that it's bad enough we have to eliminate the opacity of
> machinetype; we *certainly* don't want to start trying to make decisions
> based on the emulator binary name!)
> 
> And of course, just because a machinetype can support pci devices,
> doesn't necessarily mean that it has a builtin pci-root bus :-O
> 


It seems the way to figure it out is to run:

$qemu -M $machine -nodefaults -nodefconfig -monitor stdio <<< "info
qtree" | grep "bus:"