On Fri, May 16, 2014 at 06:29:36PM +0200, Andreas Färber wrote: > Am 16.05.2014 18:13, schrieb Eduardo Habkost: > > On Fri, May 16, 2014 at 12:12:18AM +0200, Andreas Färber wrote: > >> Am 15.05.2014 22:26, schrieb Eduardo Habkost: > >>> On Thu, May 15, 2014 at 09:44:49PM +0200, Andreas Färber wrote: > >>>> Am 30.04.2014 18:48, schrieb Eduardo Habkost: > >>>>> This flag will allow the user to choose between two modes: > >>>>> * All flags that can be enabled on the host, even if unmigratable > >>>>> (migratable=no); > >>>>> * All flags that can be enabled on the host, known to QEMU, > >>>>> and migratable (migratable=yes). > >>>>> > >>>>> The default is still migratable=false, to keep current behavior, but > >>>>> this will be changed to migratable=true by another patch. > >>>>> > >>>>> My plan was to support the "migratable" flag on all CPU classes, but > >>>>> have the default to "false" on all CPU models except "host". However, > >>>>> DeviceClass has no mechanism to allow a child class to have a different > >>>>> property default from the parent class yet, so by now only the "host" > >>>>> CPU model will support the "migratable" flag. > >>>> > >>>> Just set the new default in the derived type's instance_init? > >>> > >>> That would work. I am still assuming that one day we will allow > >>> management to query for class property defaults without instantiating > >>> objects. But even if we do it, "host" is already an exception (because > >>> the defaults depend on KVM initialization), so in this case it will be > >>> OK. > >>> > >>> So, this patch can be dropped because it will be replaced. I will also > >>> implement the other changes you requested for this patch. > >> > >> Before you make yourself too much work, have a peek at qom-cpu. :) > >> I should have all except 15 and 18, with some cleanups TBD. > > > > Thsnk! But I see two problems on current qom-cpu: > > > > * The "migratable" flag is now not affecting the results of "-cpu host" > > (host_x86_cpu_initfn()), which was the whole point of adding the > > property. > > Where did I break that? Renaming the variable and reordering it with a > comment shouldn't be a functional change... Note that some patches > needed to be applied with patch -p1 due to rebased qom-next, so maybe > there's a mismerge somewhere?
Oh, the problem is not on this specific patch, but the fact that the patch doesn't make sense without applying "Support '-cpu host' in TCG mode" first (which changes host_x86_cpu_initfn() to use x86_cpu_get_supported_feature_word() instead of kvm_arch_get_supported_cpuid() directly). > > OTOH maybe we should start writing qtests for the CPU? I've been meaning > to write one for cpu-add but didn't get to it yet. Main difficulty with writing tests for those host/check/enforce changes is that the results depend on the GET_SUPPORTED_CPUID values returned by the kernel. This may be addressed by writing a configurable fake kvm_arch_get_supported_cpuid(). Another difficulty is that the new code is about handling unknown flags, and any unknown flag may become a known one in future QEMU versions (which would then break the test). This may be addressed by adding a hack to clear an arbitrary item on a *_feature_name[] array during testing. -- Eduardo
