Adds the following missing CPUID bits:
perfctr-core : core performance counter extensions support. Enables the VM
to use extended performance counter support. It enables six
programmable counters instead of 4 counters.
clzero : instruction zeroes out the 64 byte cache line specified in RAX.
xsaveerptr : XSAVE, XSAVE, FXSAVEOPT, XSAVEC, XSAVES always save error
pointers and FXRSTOR, XRSTOR, XRSTORS always restore error
pointers.
ibpb : Indirect Branch Prediction Barrie.
xsaves : XSAVES, XRSTORS and IA32_XSS supported.
Depends on following kernel commits:
40bc47b08b6e ("kvm: x86: Enumerate support for CLZERO instruction")
504ce1954fba ("KVM: x86: Expose XSAVEERPTR to the guest")
52297436199d ("kvm: svm: Update svm_xsaves_supported")
These new features will be added in EPYC-v3. The -cpu help output after the change.
x86 EPYC-v1 AMD EPYC Processor
x86 EPYC-v2 AMD EPYC Processor (with IBPB)
x86 EPYC-v3 AMD EPYC Processor
Backports commit a16e8dbc043720abcb37fc7dca313e720b4e0f0c from qemu
ced1be70e2