On 2020/7/8 21:36, Andi Kleen wrote:
+ /*
+ * As a first step, a guest could only enable LBR feature if its cpu
+ * model is the same as the host because the LBR registers would
+ * be pass-through to the guest and they're model specific.
+ */
+ if (boot_cpu_data.x86_model != guest_cpuid_model(vcpu))
+ return false;
Could we relax this in a followon patch? (after this series is merged)
Sure, there would be a follow-on patch to relax this check after it's merged.
It's enough of the perf cap LBR version matches, don't need full model
number match.
I assume you are referring to the LBR_FMT value in the perf_capabilities.
This would require a way to configure the LBR version
from qemu.
Sure, I may propose this configuration in the QEMU community.
This would allow more flexibility, for example migration from
Icelake to Skylake and vice versa.
Yes, we need this flexibility to cover as many platforms as possible.
Thanks,
Like Xu
-Andi
