On Wed, Mar 16, 2022 at 05:48:04PM +0000, David Edmondson wrote: > On Wednesday, 2022-03-16 at 16:05:01 GMT, Daniel P. Berrangé wrote: > > > On Wed, Mar 16, 2022 at 04:57:39PM +0100, Peter Krempa wrote: > >> On Tue, Mar 08, 2022 at 12:34:38 +0100, Paolo Bonzini wrote: > >> > From: Yang Zhong <yang.zh...@intel.com> > >> > > >> > Kernel allocates 4K xstate buffer by default. For XSAVE features > >> > which require large state component (e.g. AMX), Linux kernel > >> > dynamically expands the xstate buffer only after the process has > >> > acquired the necessary permissions. Those are called dynamically- > >> > enabled XSAVE features (or dynamic xfeatures). > >> > > >> > There are separate permissions for native tasks and guests. > >> > > >> > Qemu should request the guest permissions for dynamic xfeatures > >> > which will be exposed to the guest. This only needs to be done > >> > once before the first vcpu is created. > >> > > >> > KVM implemented one new ARCH_GET_XCOMP_SUPP system attribute API to > >> > get host side supported_xcr0 and Qemu can decide if it can request > >> > dynamically enabled XSAVE features permission. > >> > https://lore.kernel.org/all/20220126152210.3044876-1-pbonz...@redhat.com/ > >> > > >> > Suggested-by: Paolo Bonzini <pbonz...@redhat.com> > >> > Signed-off-by: Yang Zhong <yang.zh...@intel.com> > >> > Signed-off-by: Jing Liu <jing2....@intel.com> > >> > Message-Id: <20220217060434.52460-4-yang.zh...@intel.com> > >> > Signed-off-by: Paolo Bonzini <pbonz...@redhat.com> > >> > --- > >> > target/i386/cpu.c | 7 +++++ > >> > target/i386/cpu.h | 4 +++ > >> > target/i386/kvm/kvm-cpu.c | 12 ++++---- > >> > target/i386/kvm/kvm.c | 57 ++++++++++++++++++++++++++++++++++++++ > >> > target/i386/kvm/kvm_i386.h | 1 + > >> > 5 files changed, 75 insertions(+), 6 deletions(-) > >> > >> With this commit qemu crashes for me when invoking the following > >> QMP command: > > > > It is way worse than that even. If you remove '-S' you get an > > immediate kaboom on startup on AMD hosts > > Which AMD CPU is in this host?
AMD EPYC 7302P With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|