On Wed, Aug 29, 2012 at 08:36:30AM -0500, Anthony Liguori wrote: > "Michael S. Tsirkin" <mst@xxxxxxxxxx> writes: > > > In preparation for adding PV EOI support, disable PV EOI by default for > > 1.1 and older machine types, to avoid CPUID changing during migration. > > > > PV EOI can still be enabled/disabled by specifying it explicitly. > > Enable for 1.1 > > -M pc-1.1 -cpu kvm64,+kvm_pv_eoi > > Disable for 1.2 > > -M pc-1.2 -cpu kvm64,-kvm_pv_eoi > > > > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > > As best I can tell, we're papering over an ABI breakage in KVM. > > If an old QEMU attempts to do a live migration on a new kernel, > migrating to an QEMU on a different box with an older kernel, it will > fail because there is state that isn't being migrated. > > This ought to be fixed in the kernel by making these features > whitelisted by userspace. > What do you mean. Userspace and only userspace decides what cpuid bits will be seen by a guest. Currently userspace enables all PV cpuid bits it finds. -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
