Thanks. I have sent a patch based off the tip here: https://www.redhat.com/archives/libvir-list/2019-December/msg00086.html I also have a patch off libvirt-4.5 which I have tested on our HW. If needed, I can send that patch as well. Ani On Dec 2, 2019, 5:22 PM +0530, Daniel P. Berrangé <berrange(a)redhat.com&gt;, wrote: On Wed, Nov 27, 2019 at 11:10:21AM +0000, Ani Sinha wrote: Hi : I see a commit in qemu that adds support for CLZERO but in CPUIDs. : commit e900135dcfb676a4019dc206395e02db5d1de0d6 Author: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de&gt; Date: Wed Sep 25 23:49:48 2019 +0200 i386: Add CPUID bit for CLZERO and XSAVEERPTR The CPUID bits CLZERO and XSAVEERPTR are availble on AMD's ZEN platform and could be passed to the guest. Signed-off-by: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de&gt; Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com&gt; Is there a corresponding change in libvirt adding this capability? Libvirt complains when I add it manually in the vm xml: # virsh create newvm.xml error: Failed to create domain from newvm.xml error: unsupported configuration: unknown CPU feature: clzero # grep clzero newvm.xml <feature policy='require' name='clzero'/> Should we add it? Yes, if it is supported by QEMU to expose to a guest, then it should be added to libvirt too. Presumably only needs add an addition to src/cpu_maps/x86_features.xml Regards, Daniel -- |: https://urldefense.proofpoint.com/v2/url?u=https-3A__berrange.com&d=D... -o- https://urldefense.proofpoint.com/v2/url?u=https-3A__www.flickr.com_photo... :| |: https://urldefense.proofpoint.com/v2/url?u=https-3A__libvirt.org&d=Dw... -o- https://urldefense.proofpoint.com/v2/url?u=https-3A__fstop138.berrange.co... :| |: https://urldefense.proofpoint.com/v2/url?u=https-3A__entangle-2Dphoto.org... -o- https://urldefense.proofpoint.com/v2/url?u=https-3A__www.instagram.com_db... :|