Re: [PATCH v4 01/16] perf/x86/intel: Add x86_pmu.pebs_vmx for Ice Lake Servers

[Liuxiangdong (Aven, Cloud Infrastructure Service Product Dept.)]

On 2021/4/6 20:47, Andi Kleen wrote:
> > AFAIK， Icelake supports adaptive PEBS and extended PEBS which Skylake
> > doesn't.
> > But we can still use IA32_PEBS_ENABLE MSR to indicate general-purpose
> > counter in Skylake.
> > Is there anything else that only Icelake supports in this patches set?
> Only Icelake server has the support for recovering from a EPT violation
> on the PEBS data structures. To use it on Skylake server you would
> need to pin the whole guest, but that is currently not done.
Sorry. Some questions about "Pin the whole guest". Do you mean VmPin 
equals VmSize
in "/proc/$(pidof qemu-kvm)/status"? Or just VmLck equals VmSize? Or 
something else?
> > Besides, we have tried this patches set in Icelake.  We can use pebs(eg:
> > "perf record -e cycles:pp")
> > when guest is kernel-5.11, but can't when kernel-4.18.  Is there a minimum
> > guest kernel version requirement?
> You would need a guest kernel that supports Icelake server PEBS. 4.18
> would need backports for tht.
>
>
> -Andi