On Fri, Sep 6, 2019 at 1:43 PM Krish Sadhukhan
<krish.sadhukhan@xxxxxxxxxx> wrote:
>
>
> On 9/6/19 1:30 PM, Jim Mattson wrote:
> > On Fri, Sep 6, 2019 at 12:59 PM Krish Sadhukhan
> > <krish.sadhukhan@xxxxxxxxxx> wrote:
> >>
> >> On 9/6/19 9:48 AM, Jim Mattson wrote:
> >>
> >> On Wed, Aug 21, 2019 at 11:20 AM Jim Mattson <jmattson@xxxxxxxxxx> wrote:
> >>
> >> These MSRs should be enumerated by KVM_GET_MSR_INDEX_LIST, so that
> >> userspace knows that these MSRs may be part of the vCPU state.
> >>
> >> Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
> >> Reviewed-by: Eric Hankland <ehankland@xxxxxxxxxx>
> >> Reviewed-by: Peter Shier <pshier@xxxxxxxxxx>
> >>
> >> ---
> >> arch/x86/kvm/x86.c | 41 +++++++++++++++++++++++++++++++++++++++++
> >> 1 file changed, 41 insertions(+)
> >>
> >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> >> index 93b0bd45ac73..ecaaa411538f 100644
> >> --- a/arch/x86/kvm/x86.c
> >> +++ b/arch/x86/kvm/x86.c
> >> @@ -1140,6 +1140,42 @@ static u32 msrs_to_save[] = {
> >> MSR_IA32_RTIT_ADDR1_A, MSR_IA32_RTIT_ADDR1_B,
> >> MSR_IA32_RTIT_ADDR2_A, MSR_IA32_RTIT_ADDR2_B,
> >> MSR_IA32_RTIT_ADDR3_A, MSR_IA32_RTIT_ADDR3_B,
> >> + MSR_ARCH_PERFMON_FIXED_CTR0, MSR_ARCH_PERFMON_FIXED_CTR1,
> >> + MSR_ARCH_PERFMON_FIXED_CTR0 + 2, MSR_ARCH_PERFMON_FIXED_CTR0 + 3,
> >> + MSR_CORE_PERF_FIXED_CTR_CTRL, MSR_CORE_PERF_GLOBAL_STATUS,
> >> + MSR_CORE_PERF_GLOBAL_CTRL, MSR_CORE_PERF_GLOBAL_OVF_CTRL,
> >> + MSR_ARCH_PERFMON_PERFCTR0, MSR_ARCH_PERFMON_PERFCTR1,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 2, MSR_ARCH_PERFMON_PERFCTR0 + 3,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 4, MSR_ARCH_PERFMON_PERFCTR0 + 5,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 6, MSR_ARCH_PERFMON_PERFCTR0 + 7,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 8, MSR_ARCH_PERFMON_PERFCTR0 + 9,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 10, MSR_ARCH_PERFMON_PERFCTR0 + 11,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 12, MSR_ARCH_PERFMON_PERFCTR0 + 13,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 14, MSR_ARCH_PERFMON_PERFCTR0 + 15,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 16, MSR_ARCH_PERFMON_PERFCTR0 + 17,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 18, MSR_ARCH_PERFMON_PERFCTR0 + 19,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 20, MSR_ARCH_PERFMON_PERFCTR0 + 21,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 22, MSR_ARCH_PERFMON_PERFCTR0 + 23,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 24, MSR_ARCH_PERFMON_PERFCTR0 + 25,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 26, MSR_ARCH_PERFMON_PERFCTR0 + 27,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 28, MSR_ARCH_PERFMON_PERFCTR0 + 29,
> >> + MSR_ARCH_PERFMON_PERFCTR0 + 30, MSR_ARCH_PERFMON_PERFCTR0 + 31,
> >> + MSR_ARCH_PERFMON_EVENTSEL0, MSR_ARCH_PERFMON_EVENTSEL1,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 2, MSR_ARCH_PERFMON_EVENTSEL0 + 3,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 4, MSR_ARCH_PERFMON_EVENTSEL0 + 5,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 6, MSR_ARCH_PERFMON_EVENTSEL0 + 7,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 8, MSR_ARCH_PERFMON_EVENTSEL0 + 9,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 10, MSR_ARCH_PERFMON_EVENTSEL0 + 11,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 12, MSR_ARCH_PERFMON_EVENTSEL0 + 13,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 14, MSR_ARCH_PERFMON_EVENTSEL0 + 15,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 16, MSR_ARCH_PERFMON_EVENTSEL0 + 17,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 18, MSR_ARCH_PERFMON_EVENTSEL0 + 19,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 20, MSR_ARCH_PERFMON_EVENTSEL0 + 21,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 22, MSR_ARCH_PERFMON_EVENTSEL0 + 23,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 24, MSR_ARCH_PERFMON_EVENTSEL0 + 25,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 26, MSR_ARCH_PERFMON_EVENTSEL0 + 27,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 28, MSR_ARCH_PERFMON_EVENTSEL0 + 29,
> >> + MSR_ARCH_PERFMON_EVENTSEL0 + 30, MSR_ARCH_PERFMON_EVENTSEL0 + 31,
> >> };
> >>
> >>
> >> Should we have separate #defines for the MSRs that are at offset from the base MSR?
> > How about macros that take an offset argument, rather than a whole
> > slew of new macros?
>
>
> Yes, that works too.
>
>
> >
> >> static unsigned num_msrs_to_save;
> >> @@ -4989,6 +5025,11 @@ static void kvm_init_msr_list(void)
> >> u32 dummy[2];
> >> unsigned i, j;
> >>
> >> + BUILD_BUG_ON_MSG(INTEL_PMC_MAX_FIXED != 4,
> >> + "Please update the fixed PMCs in msrs_to_save[]");
> >> + BUILD_BUG_ON_MSG(INTEL_PMC_MAX_GENERIC != 32,
> >> + "Please update the generic perfctr/eventsel MSRs in msrs_to_save[]");
> >>
> >>
> >> Just curious how the condition can ever become false because we are comparing two static numbers here.
> > Someone just has to change the macros. In fact, I originally developed
> > this change on a version of the kernel where INTEL_PMC_MAX_FIXED was
> > 3, and so I had:
> >
> >> + BUILD_BUG_ON_MSG(INTEL_PMC_MAX_FIXED != 3,
> >> + "Please update the fixed PMCs in msrs_to_save[]")
> > When I cherry-picked the change to Linux tip, the BUILD_BUG_ON fired,
> > and I updated the fixed PMCs in msrs_to_save[].
> >
> >> +
> >> for (i = j = 0; i < ARRAY_SIZE(msrs_to_save); i++) {
> >> if (rdmsr_safe(msrs_to_save[i], &dummy[0], &dummy[1]) < 0)
> >> continue;
> >> --
> >> 2.23.0.187.g17f5b7556c-goog
> >>
> >> Ping.
> >>
> >>
> >> Also, since these MSRs are Intel-specific, should these be enumerated via 'intel_pmu_ops' ?
> > msrs_to_save[] is filtered to remove MSRs that aren't supported on the
> > host. Or are you asking something else?
>
>
> I am referring to the fact that we are enumerating Intel-specific MSRs
> in the generic KVM code. Should there be some sort of #define guard to
> not compile the code on AMD ?
No. msrs_to_save[] contains *all* MSRs that may be relevant on some
platform. Notice that it already includes AMD-only MSRs (e.g.
MSR_VM_HSAVE_PA) and Intel-only MSRs (e.g. MSR_IA32_BNDCFGS). The MSRs
that are not relevant are filtered out in kvm_init_msr_list().
This list probably should include the AMD equivalents as well, but I
haven't looked into the AMD vPMU yet.
