Messages in this thread Patch in this message | | | From | Like Xu <> | Subject | [PATCH] kvm: x86: limit the maximum number of vPMU fixed counters to 3 | Date | Wed, 24 Jun 2020 09:59:28 +0800 |
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Some new Intel platforms (such as TGL) already have the fourth fixed counter TOPDOWN.SLOTS, but it has not been fully enabled on KVM and the host.
Therefore, we limit edx.split.num_counters_fixed to 3, so that it does not break the kvm-unit-tests PMU test case and bad-handled userspace.
Signed-off-by: Like Xu <like.xu@linux.intel.com> --- arch/x86/kvm/cpuid.c | 2 +- arch/x86/kvm/pmu.h | 2 ++ 2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 8a294f9747aa..0a2c6d2b4650 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -604,7 +604,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function) eax.split.bit_width = cap.bit_width_gp; eax.split.mask_length = cap.events_mask_len; - edx.split.num_counters_fixed = cap.num_counters_fixed; + edx.split.num_counters_fixed = min(cap.num_counters_fixed, MAX_FIXED_COUNTERS); edx.split.bit_width_fixed = cap.bit_width_fixed; edx.split.reserved = 0; diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h index ab85eed8a6cc..067fef51760c 100644 --- a/arch/x86/kvm/pmu.h +++ b/arch/x86/kvm/pmu.h @@ -15,6 +15,8 @@ #define VMWARE_BACKDOOR_PMC_REAL_TIME 0x10001 #define VMWARE_BACKDOOR_PMC_APPARENT_TIME 0x10002 +#define MAX_FIXED_COUNTERS 3 + struct kvm_event_hw_type_mapping { u8 eventsel; u8 unit_mask; -- 2.21.3
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