On 12/08/2011 05:43 PM, Eric Blake wrote:
> On 12/08/2011 03:08 PM, Laine Stump wrote:
>> (I'm thinking of appying this patch to libvirt in the F15 and F16
>> branches, as well as Rawhide. The intent is to prepare everyone for
>> qemu's removal of support for the "fedora-13" machine type, which will
>> happen in F17 (already done in Rawhide)).
>>
>> This addresses https://bugzilla.redhat.com/show_bug.cgi?id=754772 .
>> It should only be applied to Fedora builds of libvirt (it seems
>> appropriate to apply it to all versions currently in support).
>>
>> ---
>> src/conf/domain_conf.c | 52
>> ++++++++++++++++++-
>> .../qemuxml2argv-encrypted-disk.args | 2 +-
>> .../qemuxml2argv-encrypted-disk.xml | 2 +-
> The 4 line change to the testsuite is probably worth proposing upstream
> (upstream should try to favor upstream qemu names, rather than a
> Fedora-specific name),
I thought of that, but then realized that it's irrelevant, since that
config / commandline is never passed to an actual qemu, and the tests
still pass.
I can still send it separately upstream, but it needs to stay here,
since make check will otherwise fail once the rest of the patch is
applied. (I suppose I can put it in a separate patch, so that the main
patch can be the same for rawhide and F16.)
> but I agree with your decision to make the rest
> of this patch Fedora-specific, and hope that by F18 we will have
> automatically phased out enough of the offenders to not have to carry
> the patch around any longer.
>
>> +++ b/src/conf/domain_conf.c
>> @@ -8061,7 +8061,25 @@ virDomainDefPtr virDomainDefParseString(virCapsPtr
>> caps,
>> unsigned int expectedVirtTypes,
>> unsigned int flags)
>> {
>> - return virDomainDefParse(xmlStr, NULL, caps, expectedVirtTypes, flags);
>> + virDomainDefPtr def
>> + = virDomainDefParse(xmlStr, NULL, caps, expectedVirtTypes, flags);
>> +
>> + /* Fedora-specific HACK - treat fedora-13 and pc-0.13 as equivalent.
>> + * This handles the case of domains that had been saved to an image file
>> + * prior to upgrade (save or snapshot), then restarted/reverted.
>> + */
>> + if (def&& STREQ_NULLABLE(def->os.machine, "fedora-13")) {
> We want the hack to only apply to qemu guests. At first, I wondered if
> maybe we should move this into files in src/qemu/qemu_*.c; but on
> thinking about it more, that would make the problem get bigger, as there
> are multiple code paths that call this function. For the purposes of a
> hack that we don't plan to support in F18, I can live with doing it
> here. But doing it here means we have to worry about this code being
> shared by other drivers. Therefore, I think you need one additional
> piece of logic gating this hack:
>
> if (def->virtType == VIR_DOMAIN_VIRT_QEMU ||
> def->virtType == VIR_DOMAIN_VIRT_KQEMU ||
> def->virtType == VIR_DOMAIN_VIRT_KVM)
This looks really ugly to me. Is it really necessary, seeing that none
of the other hypervisor types uses the machine name "fedora-13"? As a
matter of fact it looks like os.machine is only used in 2 places outside
of domain_conf.c and the qemu directory:
*** src/xenxs/xen_xm.c:
xenParseXM[271] if (!(def->os.machine =
strdup(defaultMachine)))
*** src/vbox/vbox_tmpl.c:
<global>[3746] VIR_DEBUG("def->os.machine %s",
def->os.machine);
>> @@ -11343,8 +11361,20 @@ virDomainDefFormatInternal(virDomainDefPtr def,
>> virBufferAddLit(buf, "<type");
>> if (def->os.arch)
>> virBufferAsprintf(buf, " arch='%s'", def->os.arch);
>> - if (def->os.machine)
>> - virBufferAsprintf(buf, " machine='%s'", def->os.machine);
>> + if (def->os.machine) {
>> + /* Fedora-specific HACK - replace "fedora-13" with "pc-0.13".
>> + * This will catch XML being written to save/migration images
>> + * of domains that were running when libvirtd was restarted at
>> + * the time of upgrade.
>> + */
>> + if (STREQ_NULLABLE(def->os.machine, "fedora-13")) {
>> + virBufferAddLit(buf, " machine='pc-0.13'");
>> + VIR_WARN("substituting machine type 'fedora-13' with 'pc-0.13' "
>> + "in domain %s", def->name);
>> + } else {
>> + virBufferAsprintf(buf, " machine='%s'", def->os.machine);
> Same comment about gating this to just qemu. Also, do we want to print
> the VIR_WARN on every dumpxml, or do we want to modify def->os.machine
> in-place so that the remaining uses of the def are already at pc-0.13?
I had thought about that, but the idea of modifying an object that the
caller is expecting to not change wasn't very appealing to me. I could
be persuaded otherwise, though.
(Actually I thought I'd just removed that VIR_WARN(), because I'd
discovered that during the managedsave of a single 1GB domain,
virDomainFormatDef was called 234 times!)
>> \@@ -11779,6 +11809,22 @@ static virDomainObjPtr
>> virDomainLoadConfig(virCapsPtr caps,
>> VIR_DOMAIN_XML_INACTIVE)))
>> goto error;
>>
>> + /* Fedora-specific HACK - replace "fedora-13" with "pc-0.13".
>> + * This updates all config files at the first restart of libvirt
> s/libvirt/libvirtd/
>
>> + * after upgrade.
>> + */
>> + if (STREQ_NULLABLE(def->os.machine, "fedora-13")) {
> Again, this should be gated to just qemu.
Same comment as above. Does anyone else have an opinion on whether or
not this is necessary/desirable?
If there's one other vote in your suggested direction (or even if
there's no other votes against it), I'll do it.
> Except for the missing gating, it looks reasonable; I'll take some time
> to test a domain snapshot taken before the patch and loaded after and
> report back with that (but at first glance, it should work).
>
It may also be useful to start a domain running prior to the upgrade,
then do a snapshot after the upgrade is finished and see if it gets the
right machine type in the xml that's stored in the snapshot file.
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