KVM: x86/pmu: Do not speculatively query Intel GP PMCs that don't exist yet

The SDM lists an architectural MSR IA32_CORE_CAPABILITIES (0xCF)
that limits the theoretical maximum value of the Intel GP PMC MSRs
allocated at 0xC1 to 14; likewise the Intel April 2022 SDM adds
IA32_OVERCLOCKING_STATUS at 0x195 which limits the number of event
selection MSRs to 15 (0x186-0x194).

Limiting the maximum number of counters to 14 or 18 based on the currently
allocated MSRs is clearly fragile, and it seems likely that Intel will
even place PMCs 8-15 at a completely different range of MSR indices.
So stop at the maximum number of GP PMCs supported today on Intel
processors.

There are some machines, like Intel P4 with non Architectural PMU, that
may indeed have 18 counters, but those counters are in a completely
different MSR address range and are not supported by KVM.

Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Fixes: cf05a67b68b8 ("KVM: x86: omit "impossible" pmu MSRs from MSR list")
Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20220919091008.60695-1-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5f5eb577d583cec1aeb0a51711c963c9828e4877..73716fab120f750be686ddcb5b0cddae49896f77 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1442,20 +1442,10 @@ static const u32 msrs_to_save_all[] = {
        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_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_IA32_PEBS_ENABLE, MSR_IA32_DS_AREA, MSR_PEBS_DATA_CFG,
 
        MSR_K7_EVNTSEL0, MSR_K7_EVNTSEL1, MSR_K7_EVNTSEL2, MSR_K7_EVNTSEL3,
@@ -7041,12 +7031,12 @@ static void kvm_init_msr_list(void)
                                intel_pt_validate_hw_cap(PT_CAP_num_address_ranges) * 2)
                                continue;
                        break;
-               case MSR_ARCH_PERFMON_PERFCTR0 ... MSR_ARCH_PERFMON_PERFCTR0 + 17:
+               case MSR_ARCH_PERFMON_PERFCTR0 ... MSR_ARCH_PERFMON_PERFCTR0 + 7:
                        if (msrs_to_save_all[i] - MSR_ARCH_PERFMON_PERFCTR0 >=
                            min(INTEL_PMC_MAX_GENERIC, kvm_pmu_cap.num_counters_gp))
                                continue;
                        break;
-               case MSR_ARCH_PERFMON_EVENTSEL0 ... MSR_ARCH_PERFMON_EVENTSEL0 + 17:
+               case MSR_ARCH_PERFMON_EVENTSEL0 ... MSR_ARCH_PERFMON_EVENTSEL0 + 7:
                        if (msrs_to_save_all[i] - MSR_ARCH_PERFMON_EVENTSEL0 >=
                            min(INTEL_PMC_MAX_GENERIC, kvm_pmu_cap.num_counters_gp))
                                continue;