On 11/17/2017 5:44 AM, Borislav Petkov wrote:
On Thu, Nov 16, 2017 at 12:00:11PM -0600, Natarajan, Janakarajan wrote:
Ah my apologies. So when the pmu is initialized the cpuid entries
aren't available then.
So let's see:
... kvm_arch_vcpu_create() ->
svm_create_vcpu() ->
kvm_vcpu_init() ->
kvm_arch_vcpu_init() ->
<--- HERE
kvm_pmu_init()
But at HERE in kvm_arch_vcpu_init() right before kvm_pmu_init() we do already query
cpuid:
vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
so it's not like we don't know about cpuid leafs at that point. Which
would mean that the code can be made to set the CPU family earlier,
before kvm_pmu_init() runs so that you have the proper CPU family and
thus have this thing properly designed.
Maybe Paolo and Radim have a better suggestion here...
Paolo, Radim any suggestions about this. I feel that the number of
counters initialized can be 6
and the subsequent code (kvm_pmu_refresh()) takes care of the number of
counters to be used (4 or 6)
based on the vcpu family.
