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? > $ ./build/qemu-system-x86_64 -accel kvm > Unable to init server: Could not connect: Connection refused > qemu-system-x86_64: ../target/i386/kvm/kvm-cpu.c:105: kvm_cpu_xsave_init: > Assertion `esa->size == eax' failed. > Aborted (core dumped) > > With regards, > Daniel dme. -- My girl Friday, she no square.
