On Sun, Mar 20, 2022 at 20:39:14 +0100, Paolo Bonzini wrote: > KVM support for AMX includes a new system attribute, KVM_X86_XCOMP_GUEST_SUPP. > Commit 19db68ca68 ("x86: Grant AMX permission for guest", 2022-03-15) however > did not fully consider the behavior on older kernels. First, it warns > too aggressively. Second, it invokes the KVM_GET_DEVICE_ATTR ioctl > unconditionally and then uses the "bitmask" variable, which remains > uninitialized if the ioctl fails. Third, kvm_ioctl returns -errno rather > than -1 on errors. > > While at it, explain why the ioctl is needed and KVM_GET_SUPPORTED_CPUID > is not enough. > > Signed-off-by: Paolo Bonzini <pbonz...@redhat.com> > --- > v1->v2: for error condition for kvm_ioctl [Volker] > target/i386/kvm/kvm.c | 17 +++++++++++++---- > 1 file changed, 13 insertions(+), 4 deletions(-)
Based on the commit message it seems that this is only for the problem that Michal reported, right? Because it doesn't still fix the assertion failure on my AMD box: $ ./build/qemu-system-x86_64 -accel kvm qemu-system-x86_64: ../target/i386/kvm/kvm-cpu.c:105: kvm_cpu_xsave_init: Assertion `esa->size == eax' failed. Aborted (core dumped)