Re: [PATCH 05/32] perf, kvm: Support the intx/intx_cp modifiers in KVM arch perfmon emulation v4

[Gleb Natapov <gleb@redhat.com>]

On Fri, Nov 09, 2012 at 05:27:21PM -0800, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
> 
> This is not arch perfmon, but older CPUs will just ignore it. This makes
> it possible to do at least some TSX measurements from a KVM guest
> 
> Cc: avi@redhat.com
> Cc: gleb@redhat.com
> v2: Various fixes to address review feedback
> v3: Ignore the bits when no CPUID. No #GP. Force raw events with TSX bits.
> v4: Use reserved bits for #GP
> Cc: gleb@redhat.com
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
> ---
>  arch/x86/include/asm/kvm_host.h |    1 +
>  arch/x86/kvm/pmu.c              |   32 ++++++++++++++++++++++++--------
>  2 files changed, 25 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index b2e11f4..63d4be4 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -318,6 +318,7 @@ struct kvm_pmu {
>  	u64 global_ovf_ctrl;
>  	u64 counter_bitmask[2];
>  	u64 global_ctrl_mask;
> +	u64 reserved_bits;
>  	u8 version;
>  	struct kvm_pmc gp_counters[INTEL_PMC_MAX_GENERIC];
>  	struct kvm_pmc fixed_counters[INTEL_PMC_MAX_FIXED];
> diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
> index cfc258a..89405d0 100644
> --- a/arch/x86/kvm/pmu.c
> +++ b/arch/x86/kvm/pmu.c
> @@ -160,7 +160,7 @@ static void stop_counter(struct kvm_pmc *pmc)
>  
>  static void reprogram_counter(struct kvm_pmc *pmc, u32 type,
>  		unsigned config, bool exclude_user, bool exclude_kernel,
> -		bool intr)
> +		bool intr, bool intx, bool intx_cp)
>  {
>  	struct perf_event *event;
>  	struct perf_event_attr attr = {
> @@ -173,6 +173,10 @@ static void reprogram_counter(struct kvm_pmc *pmc, u32 type,
>  		.exclude_kernel = exclude_kernel,
>  		.config = config,
>  	};
> +	if (intx)
> +		attr.config |= HSW_INTX;
> +	if (intx_cp)
> +		attr.config |= HSW_INTX_CHECKPOINTED;
>  
>  	attr.sample_period = (-pmc->counter) & pmc_bitmask(pmc);
>  
> @@ -206,7 +210,8 @@ static unsigned find_arch_event(struct kvm_pmu *pmu, u8 event_select,
>  	return arch_events[i].event_type;
>  }
>  
> -static void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel)
> +static void reprogram_gp_counter(struct kvm_pmu *pmu, struct kvm_pmc *pmc, 
> +				 u64 eventsel)
>  {
pmu parameter is no longer used in this patch version. Otherwise looks
good.

>  	unsigned config, type = PERF_TYPE_RAW;
>  	u8 event_select, unit_mask;
> @@ -226,7 +231,9 @@ static void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel)
>  
>  	if (!(eventsel & (ARCH_PERFMON_EVENTSEL_EDGE |
>  				ARCH_PERFMON_EVENTSEL_INV |
> -				ARCH_PERFMON_EVENTSEL_CMASK))) {
> +				ARCH_PERFMON_EVENTSEL_CMASK |
> +				HSW_INTX |
> +				HSW_INTX_CHECKPOINTED))) {
>  		config = find_arch_event(&pmc->vcpu->arch.pmu, event_select,
>  				unit_mask);
>  		if (config != PERF_COUNT_HW_MAX)
> @@ -239,7 +246,9 @@ static void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel)
>  	reprogram_counter(pmc, type, config,
>  			!(eventsel & ARCH_PERFMON_EVENTSEL_USR),
>  			!(eventsel & ARCH_PERFMON_EVENTSEL_OS),
> -			eventsel & ARCH_PERFMON_EVENTSEL_INT);
> +			eventsel & ARCH_PERFMON_EVENTSEL_INT,
> +			(eventsel & HSW_INTX),
> +			(eventsel & HSW_INTX_CHECKPOINTED));
>  }
>  
>  static void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 en_pmi, int idx)
> @@ -256,7 +265,7 @@ static void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 en_pmi, int idx)
>  			arch_events[fixed_pmc_events[idx]].event_type,
>  			!(en & 0x2), /* exclude user */
>  			!(en & 0x1), /* exclude kernel */
> -			pmi);
> +			pmi, false, false);
>  }
>  
>  static inline u8 fixed_en_pmi(u64 ctrl, int idx)
> @@ -289,7 +298,7 @@ static void reprogram_idx(struct kvm_pmu *pmu, int idx)
>  		return;
>  
>  	if (pmc_is_gp(pmc))
> -		reprogram_gp_counter(pmc, pmc->eventsel);
> +		reprogram_gp_counter(pmu, pmc, pmc->eventsel);
>  	else {
>  		int fidx = idx - INTEL_PMC_IDX_FIXED;
>  		reprogram_fixed_counter(pmc,
> @@ -400,8 +409,8 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data)
>  		} else if ((pmc = get_gp_pmc(pmu, index, MSR_P6_EVNTSEL0))) {
>  			if (data == pmc->eventsel)
>  				return 0;
> -			if (!(data & 0xffffffff00200000ull)) {
> -				reprogram_gp_counter(pmc, data);
> +			if (!(data & pmu->reserved_bits)) {
> +				reprogram_gp_counter(pmu, pmc, data);
>  				return 0;
>  			}
>  		}
> @@ -442,6 +451,7 @@ void kvm_pmu_cpuid_update(struct kvm_vcpu *vcpu)
>  	pmu->counter_bitmask[KVM_PMC_GP] = 0;
>  	pmu->counter_bitmask[KVM_PMC_FIXED] = 0;
>  	pmu->version = 0;
> +	pmu->reserved_bits = 0xffffffff00200000ull;
>  
>  	entry = kvm_find_cpuid_entry(vcpu, 0xa, 0);
>  	if (!entry)
> @@ -470,6 +480,12 @@ void kvm_pmu_cpuid_update(struct kvm_vcpu *vcpu)
>  	pmu->global_ctrl = ((1 << pmu->nr_arch_gp_counters) - 1) |
>  		(((1ull << pmu->nr_arch_fixed_counters) - 1) << INTEL_PMC_IDX_FIXED);
>  	pmu->global_ctrl_mask = ~pmu->global_ctrl;
> +
> +	entry = kvm_find_cpuid_entry(vcpu, 7, 0);
> +	if (entry &&
> +	    (boot_cpu_has(X86_FEATURE_HLE) || boot_cpu_has(X86_FEATURE_RTM)) &&
> +	    (entry->ebx & (X86_FEATURE_HLE|X86_FEATURE_RTM)))
> +		pmu->reserved_bits ^= HSW_INTX|HSW_INTX_CHECKPOINTED;
>  }
>  
>  void kvm_pmu_init(struct kvm_vcpu *vcpu)
> -- 
> 1.7.7.6

--
			Gleb.