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* [PATCH v6 00/12] Guest LBR Enabling
@ 2019-06-06  7:02 Wei Wang
  2019-06-06  7:02 ` [PATCH v6 01/12] perf/x86: fix the variable type of the LBR MSRs Wei Wang
                   ` (11 more replies)
  0 siblings, 12 replies; 13+ messages in thread
From: Wei Wang @ 2019-06-06  7:02 UTC (permalink / raw)
  To: linux-kernel, kvm, pbonzini, ak, peterz
  Cc: kan.liang, mingo, rkrcmar, like.xu, wei.w.wang, jannh,
	arei.gonglei, jmattson

Last Branch Recording (LBR) is a performance monitor unit (PMU) feature
on Intel CPUs that captures branch related info. This patch series enables
this feature to KVM guests.

Here is a conclusion of the fundamental methods that we use:
1) the LBR feature is enabled per guest via QEMU setting of
   KVM_CAP_X86_GUEST_LBR;
2) the LBR stack is passed through to the guest for direct accesses after
   the guest's first access to any of the lbr related MSRs;
3) the host will help save/resotre the LBR stack when the vCPU is
   scheduled out/in.

ChangeLog:
    - perf/x86:
        - Patch 7:
                - define "no counter" as a new PERF_EV cap and keep it
                  used in the kernel, instead of esposing it in the user
                  ABI (if defined in perf_event_attr)
                - add a new API, perf_event_create, which can be used to
                  create a perf event without counter assignment (e.g.
                  a perf event simply to get the perf core's help of
                  switching lbr stack on thread switching, please see
                  patch 8)
    - KVM/vPMU:
	- Patch 8: use perf_event_create to create a perf event without
                   the need of a perf counter
	- Patch 12: set the GLOBAL_STATUS_COUNTERS_FROZEN bit when
                   injecting a vPMI.
previous:
	https://lkml.org/lkml/2019/2/14/210

Like Xu (1):
  KVM/x86/vPMU: Add APIs to support host save/restore the guest lbr
    stack

Wei Wang (11):
  perf/x86: fix the variable type of the LBR MSRs
  perf/x86: add a function to get the lbr stack
  KVM/x86: KVM_CAP_X86_GUEST_LBR
  KVM/x86: intel_pmu_lbr_enable
  KVM/x86/vPMU: tweak kvm_pmu_get_msr
  KVM/x86: expose MSR_IA32_PERF_CAPABILITIES to the guest
  perf/x86: no counter allocation support
  perf/x86: save/restore LBR_SELECT on vCPU switching
  KVM/x86/lbr: lazy save the guest lbr stack
  KVM/x86: remove the common handling of the debugctl msr
  KVM/VMX/vPMU: support to report GLOBAL_STATUS_LBRS_FROZEN

 arch/x86/events/core.c            |  12 ++
 arch/x86/events/intel/lbr.c       |  43 ++++-
 arch/x86/events/perf_event.h      |   6 +-
 arch/x86/include/asm/kvm_host.h   |   5 +
 arch/x86/include/asm/perf_event.h |  16 ++
 arch/x86/kvm/cpuid.c              |   2 +-
 arch/x86/kvm/cpuid.h              |   8 +
 arch/x86/kvm/pmu.c                |  29 ++-
 arch/x86/kvm/pmu.h                |  12 +-
 arch/x86/kvm/pmu_amd.c            |   7 +-
 arch/x86/kvm/vmx/pmu_intel.c      | 397 +++++++++++++++++++++++++++++++++++++-
 arch/x86/kvm/vmx/vmx.c            |   4 +-
 arch/x86/kvm/vmx/vmx.h            |   2 +
 arch/x86/kvm/x86.c                |  32 +--
 include/linux/perf_event.h        |  13 ++
 include/uapi/linux/kvm.h          |   1 +
 kernel/events/core.c              |  37 ++--
 17 files changed, 574 insertions(+), 52 deletions(-)

-- 
2.7.4


^ permalink raw reply	[flat|nested] 13+ messages in thread
* [PATCH v6 01/12] perf/x86: fix the variable type of the LBR MSRs
  2019-06-06  7:02 [PATCH v6 00/12] Guest LBR Enabling Wei Wang
@ 2019-06-06  7:02 ` Wei Wang
  2019-06-06  7:02 ` [PATCH v6 02/12] perf/x86: add a function to get the lbr stack Wei Wang
                   ` (10 subsequent siblings)
  11 siblings, 0 replies; 13+ messages in thread
From: Wei Wang @ 2019-06-06  7:02 UTC (permalink / raw)
  To: linux-kernel, kvm, pbonzini, ak, peterz
  Cc: kan.liang, mingo, rkrcmar, like.xu, wei.w.wang, jannh,
	arei.gonglei, jmattson

The MSR variable type can be "unsigned int", which uses less memory than
the longer unsigned long. The lbr nr won't be a negative number, so make
it "unsigned int" as well.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
---
 arch/x86/events/perf_event.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index a6ac2f4..186c1c7 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -682,8 +682,8 @@ struct x86_pmu {
 	/*
 	 * Intel LBR
 	 */
-	unsigned long	lbr_tos, lbr_from, lbr_to; /* MSR base regs       */
-	int		lbr_nr;			   /* hardware stack size */
+	unsigned int	lbr_tos, lbr_from, lbr_to,
+			lbr_nr;			   /* lbr stack and size */
 	u64		lbr_sel_mask;		   /* LBR_SELECT valid bits */
 	const int	*lbr_sel_map;		   /* lbr_select mappings */
 	bool		lbr_double_abort;	   /* duplicated lbr aborts */
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v6 02/12] perf/x86: add a function to get the lbr stack
  2019-06-06  7:02 [PATCH v6 00/12] Guest LBR Enabling Wei Wang
  2019-06-06  7:02 ` [PATCH v6 01/12] perf/x86: fix the variable type of the LBR MSRs Wei Wang
@ 2019-06-06  7:02 ` Wei Wang
  2019-06-06  7:02 ` [PATCH v6 03/12] KVM/x86: KVM_CAP_X86_GUEST_LBR Wei Wang
                   ` (9 subsequent siblings)
  11 siblings, 0 replies; 13+ messages in thread
From: Wei Wang @ 2019-06-06  7:02 UTC (permalink / raw)
  To: linux-kernel, kvm, pbonzini, ak, peterz
  Cc: kan.liang, mingo, rkrcmar, like.xu, wei.w.wang, jannh,
	arei.gonglei, jmattson

The LBR stack MSRs are architecturally specific. The perf subsystem has
already assigned the abstracted MSR values based on the CPU architecture.

This patch enables a caller outside the perf subsystem to get the LBR
stack info. This is useful for hyperviosrs to prepare the lbr feature
for the guest.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 arch/x86/events/intel/lbr.c       | 23 +++++++++++++++++++++++
 arch/x86/include/asm/perf_event.h | 14 ++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index 6f814a2..784642a 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -1311,3 +1311,26 @@ void intel_pmu_lbr_init_knl(void)
 	if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_LIP)
 		x86_pmu.intel_cap.lbr_format = LBR_FORMAT_EIP_FLAGS;
 }
+
+/**
+ * x86_perf_get_lbr_stack - get the lbr stack related MSRs
+ *
+ * @stack: the caller's memory to get the lbr stack
+ *
+ * Returns: 0 indicates that the lbr stack has been successfully obtained.
+ */
+int x86_perf_get_lbr_stack(struct x86_perf_lbr_stack *stack)
+{
+	stack->nr = x86_pmu.lbr_nr;
+	stack->tos = x86_pmu.lbr_tos;
+	stack->from = x86_pmu.lbr_from;
+	stack->to = x86_pmu.lbr_to;
+
+	if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO)
+		stack->info = MSR_LBR_INFO_0;
+	else
+		stack->info = 0;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(x86_perf_get_lbr_stack);
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 1392d5e..2606100 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -318,7 +318,16 @@ struct perf_guest_switch_msr {
 	u64 host, guest;
 };
 
+struct x86_perf_lbr_stack {
+	unsigned int	nr;
+	unsigned int	tos;
+	unsigned int	from;
+	unsigned int	to;
+	unsigned int	info;
+};
+
 extern struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr);
+extern int x86_perf_get_lbr_stack(struct x86_perf_lbr_stack *stack);
 extern void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap);
 extern void perf_check_microcode(void);
 extern int x86_perf_rdpmc_index(struct perf_event *event);
@@ -329,6 +338,11 @@ static inline struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr)
 	return NULL;
 }
 
+static inline int x86_perf_get_lbr_stack(struct x86_perf_lbr_stack *stack)
+{
+	return -1;
+}
+
 static inline void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap)
 {
 	memset(cap, 0, sizeof(*cap));
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v6 03/12] KVM/x86: KVM_CAP_X86_GUEST_LBR
  2019-06-06  7:02 [PATCH v6 00/12] Guest LBR Enabling Wei Wang
  2019-06-06  7:02 ` [PATCH v6 01/12] perf/x86: fix the variable type of the LBR MSRs Wei Wang
  2019-06-06  7:02 ` [PATCH v6 02/12] perf/x86: add a function to get the lbr stack Wei Wang
@ 2019-06-06  7:02 ` Wei Wang
  2019-06-06  7:02 ` [PATCH v6 04/12] KVM/x86: intel_pmu_lbr_enable Wei Wang
                   ` (8 subsequent siblings)
  11 siblings, 0 replies; 13+ messages in thread
From: Wei Wang @ 2019-06-06  7:02 UTC (permalink / raw)
  To: linux-kernel, kvm, pbonzini, ak, peterz
  Cc: kan.liang, mingo, rkrcmar, like.xu, wei.w.wang, jannh,
	arei.gonglei, jmattson

Introduce KVM_CAP_X86_GUEST_LBR to allow per-VM enabling of the guest
lbr feature.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 arch/x86/include/asm/kvm_host.h |  2 ++
 arch/x86/kvm/x86.c              | 14 ++++++++++++++
 include/uapi/linux/kvm.h        |  1 +
 3 files changed, 17 insertions(+)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 450d69a..a6cc967 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -874,6 +874,7 @@ struct kvm_arch {
 	atomic_t vapics_in_nmi_mode;
 	struct mutex apic_map_lock;
 	struct kvm_apic_map *apic_map;
+	struct x86_perf_lbr_stack lbr_stack;
 
 	bool apic_access_page_done;
 
@@ -882,6 +883,7 @@ struct kvm_arch {
 	bool mwait_in_guest;
 	bool hlt_in_guest;
 	bool pause_in_guest;
+	bool lbr_in_guest;
 
 	unsigned long irq_sources_bitmap;
 	s64 kvmclock_offset;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index acb179f..524e663 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3089,6 +3089,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_GET_MSR_FEATURES:
 	case KVM_CAP_MSR_PLATFORM_INFO:
 	case KVM_CAP_EXCEPTION_PAYLOAD:
+	case KVM_CAP_X86_GUEST_LBR:
 		r = 1;
 		break;
 	case KVM_CAP_SYNC_REGS:
@@ -4622,6 +4623,19 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
 		kvm->arch.exception_payload_enabled = cap->args[0];
 		r = 0;
 		break;
+	case KVM_CAP_X86_GUEST_LBR:
+		r = -EINVAL;
+		if (cap->args[0] &&
+		    x86_perf_get_lbr_stack(&kvm->arch.lbr_stack))
+			break;
+
+		if (copy_to_user((void __user *)cap->args[1],
+				 &kvm->arch.lbr_stack,
+				 sizeof(struct x86_perf_lbr_stack)))
+			break;
+		kvm->arch.lbr_in_guest = cap->args[0];
+		r = 0;
+		break;
 	default:
 		r = -EINVAL;
 		break;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 2fe12b4..5391cbc 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -993,6 +993,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_ARM_SVE 170
 #define KVM_CAP_ARM_PTRAUTH_ADDRESS 171
 #define KVM_CAP_ARM_PTRAUTH_GENERIC 172
+#define KVM_CAP_X86_GUEST_LBR 173
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v6 04/12] KVM/x86: intel_pmu_lbr_enable
  2019-06-06  7:02 [PATCH v6 00/12] Guest LBR Enabling Wei Wang
                   ` (2 preceding siblings ...)
  2019-06-06  7:02 ` [PATCH v6 03/12] KVM/x86: KVM_CAP_X86_GUEST_LBR Wei Wang
@ 2019-06-06  7:02 ` Wei Wang
  2019-06-06  7:02 ` [PATCH v6 05/12] KVM/x86/vPMU: tweak kvm_pmu_get_msr Wei Wang
                   ` (7 subsequent siblings)
  11 siblings, 0 replies; 13+ messages in thread
From: Wei Wang @ 2019-06-06  7:02 UTC (permalink / raw)
  To: linux-kernel, kvm, pbonzini, ak, peterz
  Cc: kan.liang, mingo, rkrcmar, like.xu, wei.w.wang, jannh,
	arei.gonglei, jmattson

The lbr stack is architecturally specific, for example, SKX has 32 lbr
stack entries while HSW has 16 entries, so a HSW guest running on a SKX
machine may not get accurate perf results. Currently, we forbid the
guest lbr enabling when the guest and host see different lbr stack
entries or the host and guest see different lbr stack msr indices.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 arch/x86/kvm/cpuid.h         |   8 +++
 arch/x86/kvm/pmu.c           |   8 +++
 arch/x86/kvm/pmu.h           |   2 +
 arch/x86/kvm/vmx/pmu_intel.c | 136 +++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kvm/x86.c           |   3 +-
 5 files changed, 155 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index 9a327d5..92bdc7d 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -123,6 +123,14 @@ static inline bool guest_cpuid_is_amd(struct kvm_vcpu *vcpu)
 	return best && best->ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx;
 }
 
+static inline bool guest_cpuid_is_intel(struct kvm_vcpu *vcpu)
+{
+	struct kvm_cpuid_entry2 *best;
+
+	best = kvm_find_cpuid_entry(vcpu, 0, 0);
+	return best && best->ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx;
+}
+
 static inline int guest_cpuid_family(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpuid_entry2 *best;
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index dd745b5..fea8a67 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -299,6 +299,14 @@ int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
 	return 0;
 }
 
+bool kvm_pmu_lbr_enable(struct kvm_vcpu *vcpu)
+{
+	if (guest_cpuid_is_intel(vcpu))
+		return kvm_x86_ops->pmu_ops->lbr_enable(vcpu);
+
+	return false;
+}
+
 void kvm_pmu_deliver_pmi(struct kvm_vcpu *vcpu)
 {
 	if (lapic_in_kernel(vcpu))
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 22dff66..c099b4b 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -29,6 +29,7 @@ struct kvm_pmu_ops {
 					  u64 *mask);
 	int (*is_valid_msr_idx)(struct kvm_vcpu *vcpu, unsigned idx);
 	bool (*is_valid_msr)(struct kvm_vcpu *vcpu, u32 msr);
+	bool (*lbr_enable)(struct kvm_vcpu *vcpu);
 	int (*get_msr)(struct kvm_vcpu *vcpu, u32 msr, u64 *data);
 	int (*set_msr)(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
 	void (*refresh)(struct kvm_vcpu *vcpu);
@@ -107,6 +108,7 @@ void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel);
 void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 ctrl, int fixed_idx);
 void reprogram_counter(struct kvm_pmu *pmu, int pmc_idx);
 
+bool kvm_pmu_lbr_enable(struct kvm_vcpu *vcpu);
 void kvm_pmu_deliver_pmi(struct kvm_vcpu *vcpu);
 void kvm_pmu_handle_event(struct kvm_vcpu *vcpu);
 int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned pmc, u64 *data);
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index a99613a..b465ff0 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -15,6 +15,7 @@
 #include <linux/kvm_host.h>
 #include <linux/perf_event.h>
 #include <asm/perf_event.h>
+#include <asm/intel-family.h>
 #include "x86.h"
 #include "cpuid.h"
 #include "lapic.h"
@@ -165,6 +166,140 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
 	return ret;
 }
 
+static bool intel_pmu_lbr_enable(struct kvm_vcpu *vcpu)
+{
+	struct kvm *kvm = vcpu->kvm;
+	u8 vcpu_model = guest_cpuid_model(vcpu);
+	unsigned int vcpu_lbr_from, vcpu_lbr_nr;
+
+	if (x86_perf_get_lbr_stack(&kvm->arch.lbr_stack))
+		return false;
+
+	if (guest_cpuid_family(vcpu) != boot_cpu_data.x86)
+		return false;
+
+	/*
+	 * It could be possible that people have vcpus of old model run on
+	 * physcal cpus of newer model, for example a BDW guest on a SKX
+	 * machine (but not possible to be the other way around).
+	 * The BDW guest may not get accurate results on a SKX machine as it
+	 * only reads 16 entries of the lbr stack while there are 32 entries
+	 * of recordings. We currently forbid the lbr enabling when the vcpu
+	 * and physical cpu see different lbr stack entries or the guest lbr
+	 * msr indices are not compatible with the host.
+	 */
+	switch (vcpu_model) {
+	case INTEL_FAM6_CORE2_MEROM:
+	case INTEL_FAM6_CORE2_MEROM_L:
+	case INTEL_FAM6_CORE2_PENRYN:
+	case INTEL_FAM6_CORE2_DUNNINGTON:
+		/* intel_pmu_lbr_init_core() */
+		vcpu_lbr_nr = 4;
+		vcpu_lbr_from = MSR_LBR_CORE_FROM;
+		break;
+	case INTEL_FAM6_NEHALEM:
+	case INTEL_FAM6_NEHALEM_EP:
+	case INTEL_FAM6_NEHALEM_EX:
+		/* intel_pmu_lbr_init_nhm() */
+		vcpu_lbr_nr = 16;
+		vcpu_lbr_from = MSR_LBR_NHM_FROM;
+		break;
+	case INTEL_FAM6_ATOM_BONNELL:
+	case INTEL_FAM6_ATOM_BONNELL_MID:
+	case INTEL_FAM6_ATOM_SALTWELL:
+	case INTEL_FAM6_ATOM_SALTWELL_MID:
+	case INTEL_FAM6_ATOM_SALTWELL_TABLET:
+		/* intel_pmu_lbr_init_atom() */
+		vcpu_lbr_nr = 8;
+		vcpu_lbr_from = MSR_LBR_CORE_FROM;
+		break;
+	case INTEL_FAM6_ATOM_SILVERMONT:
+	case INTEL_FAM6_ATOM_SILVERMONT_X:
+	case INTEL_FAM6_ATOM_SILVERMONT_MID:
+	case INTEL_FAM6_ATOM_AIRMONT:
+	case INTEL_FAM6_ATOM_AIRMONT_MID:
+		/* intel_pmu_lbr_init_slm() */
+		vcpu_lbr_nr = 8;
+		vcpu_lbr_from = MSR_LBR_CORE_FROM;
+		break;
+	case INTEL_FAM6_ATOM_GOLDMONT:
+	case INTEL_FAM6_ATOM_GOLDMONT_X:
+		/* intel_pmu_lbr_init_skl(); */
+		vcpu_lbr_nr = 32;
+		vcpu_lbr_from = MSR_LBR_NHM_FROM;
+		break;
+	case INTEL_FAM6_ATOM_GOLDMONT_PLUS:
+		/* intel_pmu_lbr_init_skl()*/
+		vcpu_lbr_nr = 32;
+		vcpu_lbr_from = MSR_LBR_NHM_FROM;
+		break;
+	case INTEL_FAM6_WESTMERE:
+	case INTEL_FAM6_WESTMERE_EP:
+	case INTEL_FAM6_WESTMERE_EX:
+		/* intel_pmu_lbr_init_nhm() */
+		vcpu_lbr_nr = 16;
+		vcpu_lbr_from = MSR_LBR_NHM_FROM;
+		break;
+	case INTEL_FAM6_SANDYBRIDGE:
+	case INTEL_FAM6_SANDYBRIDGE_X:
+		/* intel_pmu_lbr_init_snb() */
+		vcpu_lbr_nr = 16;
+		vcpu_lbr_from = MSR_LBR_NHM_FROM;
+		break;
+	case INTEL_FAM6_IVYBRIDGE:
+	case INTEL_FAM6_IVYBRIDGE_X:
+		/* intel_pmu_lbr_init_snb() */
+		vcpu_lbr_nr = 16;
+		vcpu_lbr_from = MSR_LBR_NHM_FROM;
+		break;
+	case INTEL_FAM6_HASWELL_CORE:
+	case INTEL_FAM6_HASWELL_X:
+	case INTEL_FAM6_HASWELL_ULT:
+	case INTEL_FAM6_HASWELL_GT3E:
+		/* intel_pmu_lbr_init_hsw() */
+		vcpu_lbr_nr = 16;
+		vcpu_lbr_from = MSR_LBR_NHM_FROM;
+		break;
+	case INTEL_FAM6_BROADWELL_CORE:
+	case INTEL_FAM6_BROADWELL_XEON_D:
+	case INTEL_FAM6_BROADWELL_GT3E:
+	case INTEL_FAM6_BROADWELL_X:
+		/* intel_pmu_lbr_init_hsw() */
+		vcpu_lbr_nr = 16;
+		vcpu_lbr_from = MSR_LBR_NHM_FROM;
+		break;
+	case INTEL_FAM6_XEON_PHI_KNL:
+	case INTEL_FAM6_XEON_PHI_KNM:
+		/* intel_pmu_lbr_init_knl() */
+		vcpu_lbr_nr = 8;
+		vcpu_lbr_from = MSR_LBR_NHM_FROM;
+		break;
+	case INTEL_FAM6_SKYLAKE_MOBILE:
+	case INTEL_FAM6_SKYLAKE_DESKTOP:
+	case INTEL_FAM6_SKYLAKE_X:
+	case INTEL_FAM6_KABYLAKE_MOBILE:
+	case INTEL_FAM6_KABYLAKE_DESKTOP:
+		/* intel_pmu_lbr_init_skl() */
+		vcpu_lbr_nr = 32;
+		vcpu_lbr_from = MSR_LBR_NHM_FROM;
+		break;
+	default:
+		vcpu_lbr_nr = 0;
+		vcpu_lbr_from = 0;
+		pr_warn("%s: vcpu model not supported %d\n", __func__,
+			vcpu_model);
+	}
+
+	if (vcpu_lbr_nr != kvm->arch.lbr_stack.nr ||
+	    vcpu_lbr_from != kvm->arch.lbr_stack.from) {
+		pr_warn("%s: vcpu model %x incompatible to pcpu %x\n",
+			__func__, vcpu_model, boot_cpu_data.x86_model);
+		return false;
+	}
+
+	return true;
+}
+
 static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -364,6 +499,7 @@ struct kvm_pmu_ops intel_pmu_ops = {
 	.msr_idx_to_pmc = intel_msr_idx_to_pmc,
 	.is_valid_msr_idx = intel_is_valid_msr_idx,
 	.is_valid_msr = intel_is_valid_msr,
+	.lbr_enable = intel_pmu_lbr_enable,
 	.get_msr = intel_pmu_get_msr,
 	.set_msr = intel_pmu_set_msr,
 	.refresh = intel_pmu_refresh,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 524e663..44a300f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4625,8 +4625,7 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
 		break;
 	case KVM_CAP_X86_GUEST_LBR:
 		r = -EINVAL;
-		if (cap->args[0] &&
-		    x86_perf_get_lbr_stack(&kvm->arch.lbr_stack))
+		if (cap->args[0] && !kvm_pmu_lbr_enable(kvm->vcpus[0]))
 			break;
 
 		if (copy_to_user((void __user *)cap->args[1],
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v6 05/12] KVM/x86/vPMU: tweak kvm_pmu_get_msr
  2019-06-06  7:02 [PATCH v6 00/12] Guest LBR Enabling Wei Wang
                   ` (3 preceding siblings ...)
  2019-06-06  7:02 ` [PATCH v6 04/12] KVM/x86: intel_pmu_lbr_enable Wei Wang
@ 2019-06-06  7:02 ` Wei Wang
  2019-06-06  7:02 ` [PATCH v6 06/12] KVM/x86: expose MSR_IA32_PERF_CAPABILITIES to the guest Wei Wang
                   ` (6 subsequent siblings)
  11 siblings, 0 replies; 13+ messages in thread
From: Wei Wang @ 2019-06-06  7:02 UTC (permalink / raw)
  To: linux-kernel, kvm, pbonzini, ak, peterz
  Cc: kan.liang, mingo, rkrcmar, like.xu, wei.w.wang, jannh,
	arei.gonglei, jmattson

This patch changes kvm_pmu_get_msr to get the msr_data struct, because
The host_initiated field from the struct could be used by get_msr. This
also makes this API be consistent with kvm_pmu_set_msr.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
---
 arch/x86/kvm/pmu.c           |  4 ++--
 arch/x86/kvm/pmu.h           |  4 ++--
 arch/x86/kvm/pmu_amd.c       |  7 ++++---
 arch/x86/kvm/vmx/pmu_intel.c | 19 +++++++++++--------
 arch/x86/kvm/x86.c           |  4 ++--
 5 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index fea8a67..6d4d1cb 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -318,9 +318,9 @@ bool kvm_pmu_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
 	return kvm_x86_ops->pmu_ops->is_valid_msr(vcpu, msr);
 }
 
-int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
+int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 {
-	return kvm_x86_ops->pmu_ops->get_msr(vcpu, msr, data);
+	return kvm_x86_ops->pmu_ops->get_msr(vcpu, msr_info);
 }
 
 int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index c099b4b..7926b65 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -30,7 +30,7 @@ struct kvm_pmu_ops {
 	int (*is_valid_msr_idx)(struct kvm_vcpu *vcpu, unsigned idx);
 	bool (*is_valid_msr)(struct kvm_vcpu *vcpu, u32 msr);
 	bool (*lbr_enable)(struct kvm_vcpu *vcpu);
-	int (*get_msr)(struct kvm_vcpu *vcpu, u32 msr, u64 *data);
+	int (*get_msr)(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
 	int (*set_msr)(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
 	void (*refresh)(struct kvm_vcpu *vcpu);
 	void (*init)(struct kvm_vcpu *vcpu);
@@ -114,7 +114,7 @@ void kvm_pmu_handle_event(struct kvm_vcpu *vcpu);
 int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned pmc, u64 *data);
 int kvm_pmu_is_valid_msr_idx(struct kvm_vcpu *vcpu, unsigned idx);
 bool kvm_pmu_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr);
-int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data);
+int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
 int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
 void kvm_pmu_refresh(struct kvm_vcpu *vcpu);
 void kvm_pmu_reset(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/pmu_amd.c b/arch/x86/kvm/pmu_amd.c
index d311808..5dda598 100644
--- a/arch/x86/kvm/pmu_amd.c
+++ b/arch/x86/kvm/pmu_amd.c
@@ -210,21 +210,22 @@ static bool amd_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
 	return ret;
 }
 
-static int amd_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
+static int amd_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 	struct kvm_pmc *pmc;
+	u32 msr = msr_info->index;
 
 	/* MSR_PERFCTRn */
 	pmc = get_gp_pmc_amd(pmu, msr, PMU_TYPE_COUNTER);
 	if (pmc) {
-		*data = pmc_read_counter(pmc);
+		msr_info->data = pmc_read_counter(pmc);
 		return 0;
 	}
 	/* MSR_EVNTSELn */
 	pmc = get_gp_pmc_amd(pmu, msr, PMU_TYPE_EVNTSEL);
 	if (pmc) {
-		*data = pmc->eventsel;
+		msr_info->data = pmc->eventsel;
 		return 0;
 	}
 
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index b465ff0..f14e764 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -300,35 +300,38 @@ static bool intel_pmu_lbr_enable(struct kvm_vcpu *vcpu)
 	return true;
 }
 
-static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
+static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 	struct kvm_pmc *pmc;
+	u32 msr = msr_info->index;
 
 	switch (msr) {
 	case MSR_CORE_PERF_FIXED_CTR_CTRL:
-		*data = pmu->fixed_ctr_ctrl;
+		msr_info->data = pmu->fixed_ctr_ctrl;
 		return 0;
 	case MSR_CORE_PERF_GLOBAL_STATUS:
-		*data = pmu->global_status;
+		msr_info->data = pmu->global_status;
 		return 0;
 	case MSR_CORE_PERF_GLOBAL_CTRL:
-		*data = pmu->global_ctrl;
+		msr_info->data = pmu->global_ctrl;
 		return 0;
 	case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
-		*data = pmu->global_ovf_ctrl;
+		msr_info->data = pmu->global_ovf_ctrl;
 		return 0;
 	default:
 		if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0))) {
 			u64 val = pmc_read_counter(pmc);
-			*data = val & pmu->counter_bitmask[KVM_PMC_GP];
+			msr_info->data =
+				val & pmu->counter_bitmask[KVM_PMC_GP];
 			return 0;
 		} else if ((pmc = get_fixed_pmc(pmu, msr))) {
 			u64 val = pmc_read_counter(pmc);
-			*data = val & pmu->counter_bitmask[KVM_PMC_FIXED];
+			msr_info->data =
+				val & pmu->counter_bitmask[KVM_PMC_FIXED];
 			return 0;
 		} else if ((pmc = get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0))) {
-			*data = pmc->eventsel;
+			msr_info->data = pmc->eventsel;
 			return 0;
 		}
 	}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 44a300f..c7ec6aa 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2793,7 +2793,7 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	case MSR_P6_PERFCTR0 ... MSR_P6_PERFCTR1:
 	case MSR_P6_EVNTSEL0 ... MSR_P6_EVNTSEL1:
 		if (kvm_pmu_is_valid_msr(vcpu, msr_info->index))
-			return kvm_pmu_get_msr(vcpu, msr_info->index, &msr_info->data);
+			return kvm_pmu_get_msr(vcpu, msr_info);
 		msr_info->data = 0;
 		break;
 	case MSR_IA32_UCODE_REV:
@@ -2945,7 +2945,7 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		break;
 	default:
 		if (kvm_pmu_is_valid_msr(vcpu, msr_info->index))
-			return kvm_pmu_get_msr(vcpu, msr_info->index, &msr_info->data);
+			return kvm_pmu_get_msr(vcpu, msr_info);
 		if (!ignore_msrs) {
 			vcpu_debug_ratelimited(vcpu, "unhandled rdmsr: 0x%x\n",
 					       msr_info->index);
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v6 06/12] KVM/x86: expose MSR_IA32_PERF_CAPABILITIES to the guest
  2019-06-06  7:02 [PATCH v6 00/12] Guest LBR Enabling Wei Wang
                   ` (4 preceding siblings ...)
  2019-06-06  7:02 ` [PATCH v6 05/12] KVM/x86/vPMU: tweak kvm_pmu_get_msr Wei Wang
@ 2019-06-06  7:02 ` Wei Wang
  2019-06-06  7:02 ` [PATCH v6 07/12] perf/x86: no counter allocation support Wei Wang
                   ` (5 subsequent siblings)
  11 siblings, 0 replies; 13+ messages in thread
From: Wei Wang @ 2019-06-06  7:02 UTC (permalink / raw)
  To: linux-kernel, kvm, pbonzini, ak, peterz
  Cc: kan.liang, mingo, rkrcmar, like.xu, wei.w.wang, jannh,
	arei.gonglei, jmattson

Bits [0, 5] of MSR_IA32_PERF_CAPABILITIES tell about the format of
the addresses stored in the LBR stack. Expose those bits to the guest
when the guest lbr feature is enabled.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
---
 arch/x86/include/asm/perf_event.h |  2 ++
 arch/x86/kvm/cpuid.c              |  2 +-
 arch/x86/kvm/vmx/pmu_intel.c      | 16 ++++++++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 2606100..aa77da2 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -95,6 +95,8 @@
 #define PEBS_DATACFG_LBRS	BIT_ULL(3)
 #define PEBS_DATACFG_LBR_SHIFT	24
 
+#define X86_PERF_CAP_MASK_LBR_FMT			0x3f
+
 /*
  * Intel "Architectural Performance Monitoring" CPUID
  * detection/enumeration details:
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index e18a9f9..c5b4264 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -364,7 +364,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 		F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ |
 		0 /* DS-CPL, VMX, SMX, EST */ |
 		0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
-		F(FMA) | F(CX16) | 0 /* xTPR Update, PDCM */ |
+		F(FMA) | F(CX16) | 0 /* xTPR Update*/ | F(PDCM) |
 		F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) |
 		F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
 		0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index f14e764..8df5e97 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -154,6 +154,7 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
 	case MSR_CORE_PERF_GLOBAL_STATUS:
 	case MSR_CORE_PERF_GLOBAL_CTRL:
 	case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
+	case MSR_IA32_PERF_CAPABILITIES:
 		ret = pmu->version > 1;
 		break;
 	default:
@@ -319,6 +320,19 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
 		msr_info->data = pmu->global_ovf_ctrl;
 		return 0;
+	case MSR_IA32_PERF_CAPABILITIES: {
+		u64 data;
+
+		if (!boot_cpu_has(X86_FEATURE_PDCM) ||
+		    (!msr_info->host_initiated &&
+		     !guest_cpuid_has(vcpu, X86_FEATURE_PDCM)))
+			return 1;
+		data = native_read_msr(MSR_IA32_PERF_CAPABILITIES);
+		msr_info->data = 0;
+		if (vcpu->kvm->arch.lbr_in_guest)
+			msr_info->data |= (data & X86_PERF_CAP_MASK_LBR_FMT);
+		return 0;
+	}
 	default:
 		if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0))) {
 			u64 val = pmc_read_counter(pmc);
@@ -377,6 +391,8 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			return 0;
 		}
 		break;
+	case MSR_IA32_PERF_CAPABILITIES:
+		return 1; /* RO MSR */
 	default:
 		if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0))) {
 			if (msr_info->host_initiated)
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v6 07/12] perf/x86: no counter allocation support
  2019-06-06  7:02 [PATCH v6 00/12] Guest LBR Enabling Wei Wang
                   ` (5 preceding siblings ...)
  2019-06-06  7:02 ` [PATCH v6 06/12] KVM/x86: expose MSR_IA32_PERF_CAPABILITIES to the guest Wei Wang
@ 2019-06-06  7:02 ` Wei Wang
  2019-06-06  7:02 ` [PATCH v6 08/12] KVM/x86/vPMU: Add APIs to support host save/restore the guest lbr stack Wei Wang
                   ` (4 subsequent siblings)
  11 siblings, 0 replies; 13+ messages in thread
From: Wei Wang @ 2019-06-06  7:02 UTC (permalink / raw)
  To: linux-kernel, kvm, pbonzini, ak, peterz
  Cc: kan.liang, mingo, rkrcmar, like.xu, wei.w.wang, jannh,
	arei.gonglei, jmattson

In some cases, an event may be created without needing a counter
allocation. For example, an lbr event may be created by the host
only to help save/restore the lbr stack on the vCPU context switching.

This patch adds a new interface to allow users to create a perf event
without the need of counter assignment.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 arch/x86/events/core.c     | 12 ++++++++++++
 include/linux/perf_event.h | 13 +++++++++++++
 kernel/events/core.c       | 37 +++++++++++++++++++++++++------------
 3 files changed, 50 insertions(+), 12 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index f315425..eebbd65 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -410,6 +410,9 @@ int x86_setup_perfctr(struct perf_event *event)
 	struct hw_perf_event *hwc = &event->hw;
 	u64 config;
 
+	if (is_no_counter_event(event))
+		return 0;
+
 	if (!is_sampling_event(event)) {
 		hwc->sample_period = x86_pmu.max_period;
 		hwc->last_period = hwc->sample_period;
@@ -1248,6 +1251,12 @@ static int x86_pmu_add(struct perf_event *event, int flags)
 	hwc = &event->hw;
 
 	n0 = cpuc->n_events;
+
+	if (is_no_counter_event(event)) {
+		n = n0;
+		goto done_collect;
+	}
+
 	ret = n = collect_events(cpuc, event, false);
 	if (ret < 0)
 		goto out;
@@ -1422,6 +1431,9 @@ static void x86_pmu_del(struct perf_event *event, int flags)
 	if (cpuc->txn_flags & PERF_PMU_TXN_ADD)
 		goto do_del;
 
+	if (is_no_counter_event(event))
+		goto do_del;
+
 	/*
 	 * Not a TXN, therefore cleanup properly.
 	 */
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 0ab99c7..19e6593 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -528,6 +528,7 @@ typedef void (*perf_overflow_handler_t)(struct perf_event *,
  */
 #define PERF_EV_CAP_SOFTWARE		BIT(0)
 #define PERF_EV_CAP_READ_ACTIVE_PKG	BIT(1)
+#define PERF_EV_CAP_NO_COUNTER		BIT(2)
 
 #define SWEVENT_HLIST_BITS		8
 #define SWEVENT_HLIST_SIZE		(1 << SWEVENT_HLIST_BITS)
@@ -895,6 +896,13 @@ extern int perf_event_refresh(struct perf_event *event, int refresh);
 extern void perf_event_update_userpage(struct perf_event *event);
 extern int perf_event_release_kernel(struct perf_event *event);
 extern struct perf_event *
+perf_event_create(struct perf_event_attr *attr,
+		  int cpu,
+		  struct task_struct *task,
+		  perf_overflow_handler_t overflow_handler,
+		  void *context,
+		  bool counter_assignment);
+extern struct perf_event *
 perf_event_create_kernel_counter(struct perf_event_attr *attr,
 				int cpu,
 				struct task_struct *task,
@@ -1032,6 +1040,11 @@ static inline bool is_sampling_event(struct perf_event *event)
 	return event->attr.sample_period != 0;
 }
 
+static inline bool is_no_counter_event(struct perf_event *event)
+{
+	return !!(event->event_caps & PERF_EV_CAP_NO_COUNTER);
+}
+
 /*
  * Return 1 for a software event, 0 for a hardware event
  */
diff --git a/kernel/events/core.c b/kernel/events/core.c
index abbd4b3..70884df 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11162,18 +11162,10 @@ SYSCALL_DEFINE5(perf_event_open,
 	return err;
 }
 
-/**
- * perf_event_create_kernel_counter
- *
- * @attr: attributes of the counter to create
- * @cpu: cpu in which the counter is bound
- * @task: task to profile (NULL for percpu)
- */
-struct perf_event *
-perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
-				 struct task_struct *task,
-				 perf_overflow_handler_t overflow_handler,
-				 void *context)
+struct perf_event *perf_event_create(struct perf_event_attr *attr, int cpu,
+				     struct task_struct *task,
+				     perf_overflow_handler_t overflow_handler,
+				     void *context, bool need_counter)
 {
 	struct perf_event_context *ctx;
 	struct perf_event *event;
@@ -11193,6 +11185,9 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
 	/* Mark owner so we could distinguish it from user events. */
 	event->owner = TASK_TOMBSTONE;
 
+	if (!need_counter)
+		event->event_caps |= PERF_EV_CAP_NO_COUNTER;
+
 	ctx = find_get_context(event->pmu, task, event);
 	if (IS_ERR(ctx)) {
 		err = PTR_ERR(ctx);
@@ -11241,6 +11236,24 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
 err:
 	return ERR_PTR(err);
 }
+EXPORT_SYMBOL_GPL(perf_event_create);
+
+/**
+ * perf_event_create_kernel_counter
+ *
+ * @attr: attributes of the counter to create
+ * @cpu: cpu in which the counter is bound
+ * @task: task to profile (NULL for percpu)
+ */
+struct perf_event *
+perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
+				 struct task_struct *task,
+				 perf_overflow_handler_t overflow_handler,
+				 void *context)
+{
+	return perf_event_create(attr, cpu, task, overflow_handler,
+				 context, true);
+}
 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
 
 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v6 08/12] KVM/x86/vPMU: Add APIs to support host save/restore the guest lbr stack
  2019-06-06  7:02 [PATCH v6 00/12] Guest LBR Enabling Wei Wang
                   ` (6 preceding siblings ...)
  2019-06-06  7:02 ` [PATCH v6 07/12] perf/x86: no counter allocation support Wei Wang
@ 2019-06-06  7:02 ` Wei Wang
  2019-06-06  7:02 ` [PATCH v6 09/12] perf/x86: save/restore LBR_SELECT on vCPU switching Wei Wang
                   ` (3 subsequent siblings)
  11 siblings, 0 replies; 13+ messages in thread
From: Wei Wang @ 2019-06-06  7:02 UTC (permalink / raw)
  To: linux-kernel, kvm, pbonzini, ak, peterz
  Cc: kan.liang, mingo, rkrcmar, like.xu, wei.w.wang, jannh,
	arei.gonglei, jmattson

From: Like Xu <like.xu@intel.com>

This patch adds support to enable/disable the host side save/restore
for the guest lbr stack on vCPU switching. To enable that, the host
creates a perf event for the vCPU, and the event attributes are set
to the user callstack mode lbr so that all the conditions are meet in
the host perf subsystem to save the lbr stack on task switching.

The host side lbr perf event are created only for the purpose of saving
and restoring the lbr stack. There is no need to enable the lbr
functionality for this perf event, because the feature is essentially
used in the vCPU. So perf_event_create is invoked with need_counter=false
to get no counter assigned for the perf event.

The vcpu_lbr field is added to cpuc, to indicate if the lbr perf event is
used by the vCPU only for context switching. When the perf subsystem
handles this event (e.g. lbr enable or read lbr stack on PMI) and finds
it's non-zero, it simply returns.

Signed-off-by: Like Xu <like.xu@intel.com>
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 arch/x86/events/intel/lbr.c     | 13 +++++++--
 arch/x86/events/perf_event.h    |  1 +
 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/kvm/pmu.h              |  3 ++
 arch/x86/kvm/vmx/pmu_intel.c    | 61 +++++++++++++++++++++++++++++++++++++++++
 5 files changed, 76 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index 784642a..118764b 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -462,6 +462,9 @@ void intel_pmu_lbr_add(struct perf_event *event)
 	if (!x86_pmu.lbr_nr)
 		return;
 
+	if (event->attr.exclude_guest && is_no_counter_event(event))
+		cpuc->vcpu_lbr = 1;
+
 	cpuc->br_sel = event->hw.branch_reg.reg;
 
 	if (branch_user_callstack(cpuc->br_sel) && event->ctx->task_ctx_data) {
@@ -509,6 +512,9 @@ void intel_pmu_lbr_del(struct perf_event *event)
 		task_ctx->lbr_callstack_users--;
 	}
 
+	if (event->attr.exclude_guest && is_no_counter_event(event))
+		cpuc->vcpu_lbr = 0;
+
 	if (x86_pmu.intel_cap.pebs_baseline && event->attr.precise_ip > 0)
 		cpuc->lbr_pebs_users--;
 	cpuc->lbr_users--;
@@ -521,7 +527,7 @@ void intel_pmu_lbr_enable_all(bool pmi)
 {
 	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
 
-	if (cpuc->lbr_users)
+	if (cpuc->lbr_users && !cpuc->vcpu_lbr)
 		__intel_pmu_lbr_enable(pmi);
 }
 
@@ -529,7 +535,7 @@ void intel_pmu_lbr_disable_all(void)
 {
 	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
 
-	if (cpuc->lbr_users)
+	if (cpuc->lbr_users && !cpuc->vcpu_lbr)
 		__intel_pmu_lbr_disable();
 }
 
@@ -669,7 +675,8 @@ void intel_pmu_lbr_read(void)
 	 * This could be smarter and actually check the event,
 	 * but this simple approach seems to work for now.
 	 */
-	if (!cpuc->lbr_users || cpuc->lbr_users == cpuc->lbr_pebs_users)
+	if (!cpuc->lbr_users || cpuc->vcpu_lbr ||
+	    cpuc->lbr_users == cpuc->lbr_pebs_users)
 		return;
 
 	if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_32)
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 186c1c7..86605d1 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -238,6 +238,7 @@ struct cpu_hw_events {
 	/*
 	 * Intel LBR bits
 	 */
+	u8				vcpu_lbr;
 	int				lbr_users;
 	int				lbr_pebs_users;
 	struct perf_branch_stack	lbr_stack;
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index a6cc967..d0f59ea 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -477,6 +477,7 @@ struct kvm_pmu {
 	struct kvm_pmc fixed_counters[INTEL_PMC_MAX_FIXED];
 	struct irq_work irq_work;
 	u64 reprogram_pmi;
+	struct perf_event *vcpu_lbr_event;
 };
 
 struct kvm_pmu_ops;
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 7926b65..384a0b7 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -123,6 +123,9 @@ void kvm_pmu_destroy(struct kvm_vcpu *vcpu);
 
 bool is_vmware_backdoor_pmc(u32 pmc_idx);
 
+extern int intel_pmu_enable_save_guest_lbr(struct kvm_vcpu *vcpu);
+extern void intel_pmu_disable_save_guest_lbr(struct kvm_vcpu *vcpu);
+
 extern struct kvm_pmu_ops intel_pmu_ops;
 extern struct kvm_pmu_ops amd_pmu_ops;
 #endif /* __KVM_X86_PMU_H */
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 8df5e97..ca7a914 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -510,6 +510,67 @@ static void intel_pmu_reset(struct kvm_vcpu *vcpu)
 		pmu->global_ovf_ctrl = 0;
 }
 
+int intel_pmu_enable_save_guest_lbr(struct kvm_vcpu *vcpu)
+{
+	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+	struct perf_event *event;
+
+	/*
+	 * The main purpose of this perf event is to have the host perf core
+	 * help save/restore the guest lbr stack on vcpu switching. There is
+	 * no perf counters allocated for the event.
+	 *
+	 * About the attr:
+	 * exclude_guest: set to true to indicate that the event runs on the
+	 *                host only.
+	 * pinned:        set to false, so that the FLEXIBLE events will not
+	 *                be rescheduled for this event which actually doesn't
+	 *                need a perf counter.
+	 * config:        Actually this field won't be used by the perf core
+	 *                as this event doesn't have a perf counter.
+	 * sample_period: Same as above.
+	 * sample_type:   tells the perf core that it is an lbr event.
+	 * branch_sample_type: tells the perf core that the lbr event works in
+	 *                the user callstack mode so that the lbr stack will be
+	 *                saved/restored on vCPU switching.
+	 */
+	struct perf_event_attr attr = {
+		.type = PERF_TYPE_RAW,
+		.size = sizeof(attr),
+		.exclude_guest = true,
+		.pinned = false,
+		.config = 0,
+		.sample_period = 0,
+		.sample_type = PERF_SAMPLE_BRANCH_STACK,
+		.branch_sample_type = PERF_SAMPLE_BRANCH_CALL_STACK |
+				      PERF_SAMPLE_BRANCH_USER,
+	};
+
+	if (pmu->vcpu_lbr_event)
+		return 0;
+
+	event = perf_event_create(&attr, -1, current, NULL, NULL, false);
+	if (IS_ERR(event)) {
+		pr_err("%s: failed %ld\n", __func__, PTR_ERR(event));
+		return -ENOENT;
+	}
+	pmu->vcpu_lbr_event = event;
+
+	return 0;
+}
+
+void intel_pmu_disable_save_guest_lbr(struct kvm_vcpu *vcpu)
+{
+	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+	struct perf_event *event = pmu->vcpu_lbr_event;
+
+	if (!event)
+		return;
+
+	perf_event_release_kernel(event);
+	pmu->vcpu_lbr_event = NULL;
+}
+
 struct kvm_pmu_ops intel_pmu_ops = {
 	.find_arch_event = intel_find_arch_event,
 	.find_fixed_event = intel_find_fixed_event,
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v6 09/12] perf/x86: save/restore LBR_SELECT on vCPU switching
  2019-06-06  7:02 [PATCH v6 00/12] Guest LBR Enabling Wei Wang
                   ` (7 preceding siblings ...)
  2019-06-06  7:02 ` [PATCH v6 08/12] KVM/x86/vPMU: Add APIs to support host save/restore the guest lbr stack Wei Wang
@ 2019-06-06  7:02 ` Wei Wang
  2019-06-06  7:02 ` [PATCH v6 10/12] KVM/x86/lbr: lazy save the guest lbr stack Wei Wang
                   ` (2 subsequent siblings)
  11 siblings, 0 replies; 13+ messages in thread
From: Wei Wang @ 2019-06-06  7:02 UTC (permalink / raw)
  To: linux-kernel, kvm, pbonzini, ak, peterz
  Cc: kan.liang, mingo, rkrcmar, like.xu, wei.w.wang, jannh,
	arei.gonglei, jmattson

The vCPU lbr event relies on the host to save/restore all the lbr
related MSRs. So add the LBR_SELECT save/restore to the related
functions for the vCPU case.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
---
 arch/x86/events/intel/lbr.c  | 7 +++++++
 arch/x86/events/perf_event.h | 1 +
 2 files changed, 8 insertions(+)

diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index 118764b..4861a9d 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -383,6 +383,9 @@ static void __intel_pmu_lbr_restore(struct x86_perf_task_context *task_ctx)
 
 	wrmsrl(x86_pmu.lbr_tos, tos);
 	task_ctx->lbr_stack_state = LBR_NONE;
+
+	if (cpuc->vcpu_lbr)
+		wrmsrl(MSR_LBR_SELECT, task_ctx->lbr_sel);
 }
 
 static void __intel_pmu_lbr_save(struct x86_perf_task_context *task_ctx)
@@ -409,6 +412,10 @@ static void __intel_pmu_lbr_save(struct x86_perf_task_context *task_ctx)
 		if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO)
 			rdmsrl(MSR_LBR_INFO_0 + lbr_idx, task_ctx->lbr_info[i]);
 	}
+
+	if (cpuc->vcpu_lbr)
+		rdmsrl(MSR_LBR_SELECT, task_ctx->lbr_sel);
+
 	task_ctx->valid_lbrs = i;
 	task_ctx->tos = tos;
 	task_ctx->lbr_stack_state = LBR_VALID;
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 86605d1..e37ff82 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -721,6 +721,7 @@ struct x86_perf_task_context {
 	u64 lbr_from[MAX_LBR_ENTRIES];
 	u64 lbr_to[MAX_LBR_ENTRIES];
 	u64 lbr_info[MAX_LBR_ENTRIES];
+	u64 lbr_sel;
 	int tos;
 	int valid_lbrs;
 	int lbr_callstack_users;
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v6 10/12] KVM/x86/lbr: lazy save the guest lbr stack
  2019-06-06  7:02 [PATCH v6 00/12] Guest LBR Enabling Wei Wang
                   ` (8 preceding siblings ...)
  2019-06-06  7:02 ` [PATCH v6 09/12] perf/x86: save/restore LBR_SELECT on vCPU switching Wei Wang
@ 2019-06-06  7:02 ` Wei Wang
  2019-06-06  7:02 ` [PATCH v6 11/12] KVM/x86: remove the common handling of the debugctl msr Wei Wang
  2019-06-06  7:02 ` [PATCH v6 12/12] KVM/VMX/vPMU: support to report GLOBAL_STATUS_LBRS_FROZEN Wei Wang
  11 siblings, 0 replies; 13+ messages in thread
From: Wei Wang @ 2019-06-06  7:02 UTC (permalink / raw)
  To: linux-kernel, kvm, pbonzini, ak, peterz
  Cc: kan.liang, mingo, rkrcmar, like.xu, wei.w.wang, jannh,
	arei.gonglei, jmattson

When the vCPU is scheduled in:
- if the lbr feature was used in the last vCPU time slice, set the lbr
  stack to be interceptible, so that the host can capture whether the
  lbr feature will be used in this time slice;
- if the lbr feature wasn't used in the last vCPU time slice, disable
  the vCPU support of the guest lbr switching.

Upon the first access to one of the lbr related MSRs (since the vCPU was
scheduled in):
- record that the guest has used the lbr;
- create a host perf event to help save/restore the guest lbr stack;
- pass the stack through to the guest.

Suggested-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 arch/x86/include/asm/kvm_host.h |   2 +
 arch/x86/kvm/pmu.c              |   6 ++
 arch/x86/kvm/pmu.h              |   2 +
 arch/x86/kvm/vmx/pmu_intel.c    | 146 ++++++++++++++++++++++++++++++++++++++++
 arch/x86/kvm/vmx/vmx.c          |   4 +-
 arch/x86/kvm/vmx/vmx.h          |   2 +
 arch/x86/kvm/x86.c              |   2 +
 7 files changed, 162 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index d0f59ea..93957a7 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -472,6 +472,8 @@ struct kvm_pmu {
 	u64 global_ctrl_mask;
 	u64 global_ovf_ctrl_mask;
 	u64 reserved_bits;
+	/* Indicate if the lbr msrs were accessed in this vCPU time slice */
+	bool lbr_used;
 	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 6d4d1cb..1e313f3 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -328,6 +328,12 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	return kvm_x86_ops->pmu_ops->set_msr(vcpu, msr_info);
 }
 
+void kvm_pmu_sched_in(struct kvm_vcpu *vcpu, int cpu)
+{
+	if (kvm_x86_ops->pmu_ops->sched_in)
+		kvm_x86_ops->pmu_ops->sched_in(vcpu, cpu);
+}
+
 /* refresh PMU settings. This function generally is called when underlying
  * settings are changed (such as changes of PMU CPUID by guest VMs), which
  * should rarely happen.
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 384a0b7..cadf91a 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -32,6 +32,7 @@ struct kvm_pmu_ops {
 	bool (*lbr_enable)(struct kvm_vcpu *vcpu);
 	int (*get_msr)(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
 	int (*set_msr)(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
+	void (*sched_in)(struct kvm_vcpu *vcpu, int cpu);
 	void (*refresh)(struct kvm_vcpu *vcpu);
 	void (*init)(struct kvm_vcpu *vcpu);
 	void (*reset)(struct kvm_vcpu *vcpu);
@@ -116,6 +117,7 @@ int kvm_pmu_is_valid_msr_idx(struct kvm_vcpu *vcpu, unsigned idx);
 bool kvm_pmu_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr);
 int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
 int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
+void kvm_pmu_sched_in(struct kvm_vcpu *vcpu, int cpu);
 void kvm_pmu_refresh(struct kvm_vcpu *vcpu);
 void kvm_pmu_reset(struct kvm_vcpu *vcpu);
 void kvm_pmu_init(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index ca7a914..c60f564 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -16,10 +16,12 @@
 #include <linux/perf_event.h>
 #include <asm/perf_event.h>
 #include <asm/intel-family.h>
+#include <asm/vmx.h>
 #include "x86.h"
 #include "cpuid.h"
 #include "lapic.h"
 #include "pmu.h"
+#include "vmx.h"
 
 static struct kvm_event_hw_type_mapping intel_arch_events[] = {
 	/* Index must match CPUID 0x0A.EBX bit vector */
@@ -144,6 +146,17 @@ static struct kvm_pmc *intel_msr_idx_to_pmc(struct kvm_vcpu *vcpu,
 	return &counters[idx];
 }
 
+static inline bool msr_is_lbr_stack(struct kvm_vcpu *vcpu, u32 index)
+{
+	struct x86_perf_lbr_stack *stack = &vcpu->kvm->arch.lbr_stack;
+	int nr = stack->nr;
+
+	return !!(index == stack->tos ||
+		 (index >= stack->from && index < stack->from + nr) ||
+		 (index >= stack->to && index < stack->to + nr) ||
+		 (index >= stack->info && index < stack->info));
+}
+
 static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -155,9 +168,13 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
 	case MSR_CORE_PERF_GLOBAL_CTRL:
 	case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
 	case MSR_IA32_PERF_CAPABILITIES:
+	case MSR_IA32_DEBUGCTLMSR:
+	case MSR_LBR_SELECT:
 		ret = pmu->version > 1;
 		break;
 	default:
+		if (msr_is_lbr_stack(vcpu, msr))
+			return pmu->version > 1;
 		ret = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0) ||
 			get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0) ||
 			get_fixed_pmc(pmu, msr);
@@ -301,6 +318,109 @@ static bool intel_pmu_lbr_enable(struct kvm_vcpu *vcpu)
 	return true;
 }
 
+static void intel_pmu_set_intercept_for_lbr_msrs(struct kvm_vcpu *vcpu,
+						 bool set)
+{
+	unsigned long *msr_bitmap = to_vmx(vcpu)->vmcs01.msr_bitmap;
+	struct x86_perf_lbr_stack *stack = &vcpu->kvm->arch.lbr_stack;
+	int nr = stack->nr;
+	int i;
+
+	vmx_set_intercept_for_msr(msr_bitmap, stack->tos, MSR_TYPE_RW, set);
+	for (i = 0; i < nr; i++) {
+		vmx_set_intercept_for_msr(msr_bitmap, stack->from + i,
+					  MSR_TYPE_RW, set);
+		vmx_set_intercept_for_msr(msr_bitmap, stack->to + i,
+					  MSR_TYPE_RW, set);
+		if (stack->info)
+			vmx_set_intercept_for_msr(msr_bitmap, stack->info + i,
+						  MSR_TYPE_RW, set);
+	}
+}
+
+static bool intel_pmu_get_lbr_msr(struct kvm_vcpu *vcpu,
+			      struct msr_data *msr_info)
+{
+	u32 index = msr_info->index;
+	bool ret = false;
+
+	switch (index) {
+	case MSR_IA32_DEBUGCTLMSR:
+		msr_info->data = vmcs_read64(GUEST_IA32_DEBUGCTL);
+		ret = true;
+		break;
+	case MSR_LBR_SELECT:
+		ret = true;
+		rdmsrl(index, msr_info->data);
+		break;
+	default:
+		if (msr_is_lbr_stack(vcpu, index)) {
+			ret = true;
+			rdmsrl(index, msr_info->data);
+		}
+	}
+
+	return ret;
+}
+
+static bool intel_pmu_set_lbr_msr(struct kvm_vcpu *vcpu,
+				  struct msr_data *msr_info)
+{
+	u32 index = msr_info->index;
+	u64 data = msr_info->data;
+	bool ret = false;
+
+	switch (index) {
+	case MSR_IA32_DEBUGCTLMSR:
+		ret = true;
+		/*
+		 * Currently, only FREEZE_LBRS_ON_PMI and DEBUGCTLMSR_LBR are
+		 * supported.
+		 */
+		data &= (DEBUGCTLMSR_FREEZE_LBRS_ON_PMI | DEBUGCTLMSR_LBR);
+		vmcs_write64(GUEST_IA32_DEBUGCTL, data);
+		break;
+	case MSR_LBR_SELECT:
+		ret = true;
+		wrmsrl(index, data);
+		break;
+	default:
+		if (msr_is_lbr_stack(vcpu, index)) {
+			ret = true;
+			wrmsrl(index, data);
+		}
+	}
+
+	return ret;
+}
+
+static bool intel_pmu_access_lbr_msr(struct kvm_vcpu *vcpu,
+				 struct msr_data *msr_info,
+				 bool set)
+{
+	bool ret = false;
+
+	/*
+	 * Some userspace implementations (e.g. QEMU) expects the msrs to be
+	 * always accesible.
+	 */
+	if (!msr_info->host_initiated && !vcpu->kvm->arch.lbr_in_guest)
+		return false;
+
+	if (set)
+		ret = intel_pmu_set_lbr_msr(vcpu, msr_info);
+	else
+		ret = intel_pmu_get_lbr_msr(vcpu, msr_info);
+
+	if (ret && !vcpu->arch.pmu.lbr_used) {
+		vcpu->arch.pmu.lbr_used = true;
+		intel_pmu_set_intercept_for_lbr_msrs(vcpu, false);
+		intel_pmu_enable_save_guest_lbr(vcpu);
+	}
+
+	return ret;
+}
+
 static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -347,6 +467,8 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		} else if ((pmc = get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0))) {
 			msr_info->data = pmc->eventsel;
 			return 0;
+		} else if (intel_pmu_access_lbr_msr(vcpu, msr_info, false)) {
+			return 0;
 		}
 	}
 
@@ -410,12 +532,33 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 				reprogram_gp_counter(pmc, data);
 				return 0;
 			}
+		} else if (intel_pmu_access_lbr_msr(vcpu, msr_info, true)) {
+			return 0;
 		}
 	}
 
 	return 1;
 }
 
+static void intel_pmu_sched_in(struct kvm_vcpu *vcpu, int cpu)
+{
+	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
+	u64 guest_debugctl;
+
+	if (pmu->lbr_used) {
+		pmu->lbr_used = false;
+		intel_pmu_set_intercept_for_lbr_msrs(vcpu, true);
+	} else if (pmu->vcpu_lbr_event) {
+		/*
+		 * The lbr feature wasn't used during that last vCPU time
+		 * slice, so it's time to disable the vCPU side save/restore.
+		 */
+		guest_debugctl = vmcs_read64(GUEST_IA32_DEBUGCTL);
+		if (!(guest_debugctl & DEBUGCTLMSR_LBR))
+			intel_pmu_disable_save_guest_lbr(vcpu);
+	}
+}
+
 static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -508,6 +651,8 @@ static void intel_pmu_reset(struct kvm_vcpu *vcpu)
 
 	pmu->fixed_ctr_ctrl = pmu->global_ctrl = pmu->global_status =
 		pmu->global_ovf_ctrl = 0;
+
+	intel_pmu_disable_save_guest_lbr(vcpu);
 }
 
 int intel_pmu_enable_save_guest_lbr(struct kvm_vcpu *vcpu)
@@ -582,6 +727,7 @@ struct kvm_pmu_ops intel_pmu_ops = {
 	.lbr_enable = intel_pmu_lbr_enable,
 	.get_msr = intel_pmu_get_msr,
 	.set_msr = intel_pmu_set_msr,
+	.sched_in = intel_pmu_sched_in,
 	.refresh = intel_pmu_refresh,
 	.init = intel_pmu_init,
 	.reset = intel_pmu_reset,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index b93e36d..191d4b9 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -3526,8 +3526,8 @@ static __always_inline void vmx_enable_intercept_for_msr(unsigned long *msr_bitm
 	}
 }
 
-static __always_inline void vmx_set_intercept_for_msr(unsigned long *msr_bitmap,
-			     			      u32 msr, int type, bool value)
+void vmx_set_intercept_for_msr(unsigned long *msr_bitmap, u32 msr, int type,
+			       bool value)
 {
 	if (value)
 		vmx_enable_intercept_for_msr(msr_bitmap, msr, type);
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 61128b4..ed94909 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -317,6 +317,8 @@ void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu);
 bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu);
 void vmx_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked);
 void vmx_set_virtual_apic_mode(struct kvm_vcpu *vcpu);
+void vmx_set_intercept_for_msr(unsigned long *msr_bitmap, u32 msr, int type,
+			       bool value);
 struct shared_msr_entry *find_msr_entry(struct vcpu_vmx *vmx, u32 msr);
 void pt_update_intercept_for_msr(struct vcpu_vmx *vmx);
 void vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c7ec6aa..1ae5916 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9233,6 +9233,8 @@ void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
 void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu)
 {
 	vcpu->arch.l1tf_flush_l1d = true;
+
+	kvm_pmu_sched_in(vcpu, cpu);
 	kvm_x86_ops->sched_in(vcpu, cpu);
 }
 
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v6 11/12] KVM/x86: remove the common handling of the debugctl msr
  2019-06-06  7:02 [PATCH v6 00/12] Guest LBR Enabling Wei Wang
                   ` (9 preceding siblings ...)
  2019-06-06  7:02 ` [PATCH v6 10/12] KVM/x86/lbr: lazy save the guest lbr stack Wei Wang
@ 2019-06-06  7:02 ` Wei Wang
  2019-06-06  7:02 ` [PATCH v6 12/12] KVM/VMX/vPMU: support to report GLOBAL_STATUS_LBRS_FROZEN Wei Wang
  11 siblings, 0 replies; 13+ messages in thread
From: Wei Wang @ 2019-06-06  7:02 UTC (permalink / raw)
  To: linux-kernel, kvm, pbonzini, ak, peterz
  Cc: kan.liang, mingo, rkrcmar, like.xu, wei.w.wang, jannh,
	arei.gonglei, jmattson

The debugctl msr is not completely identical on AMD and Intel CPUs, for
example, FREEZE_LBRS_ON_PMI is supported by Intel CPUs only. Now, this
msr is handled separatedly in svm.c and intel_pmu.c. So remove the
common debugctl msr handling code in kvm_get/set_msr_common.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 arch/x86/kvm/x86.c | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1ae5916..94ebb2a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2516,18 +2516,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			return 1;
 		}
 		break;
-	case MSR_IA32_DEBUGCTLMSR:
-		if (!data) {
-			/* We support the non-activated case already */
-			break;
-		} else if (data & ~(DEBUGCTLMSR_LBR | DEBUGCTLMSR_BTF)) {
-			/* Values other than LBR and BTF are vendor-specific,
-			   thus reserved and should throw a #GP */
-			return 1;
-		}
-		vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
-			    __func__, data);
-		break;
 	case 0x200 ... 0x2ff:
 		return kvm_mtrr_set_msr(vcpu, msr, data);
 	case MSR_IA32_APICBASE:
@@ -2769,7 +2757,6 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	switch (msr_info->index) {
 	case MSR_IA32_PLATFORM_ID:
 	case MSR_IA32_EBL_CR_POWERON:
-	case MSR_IA32_DEBUGCTLMSR:
 	case MSR_IA32_LASTBRANCHFROMIP:
 	case MSR_IA32_LASTBRANCHTOIP:
 	case MSR_IA32_LASTINTFROMIP:
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v6 12/12] KVM/VMX/vPMU: support to report GLOBAL_STATUS_LBRS_FROZEN
  2019-06-06  7:02 [PATCH v6 00/12] Guest LBR Enabling Wei Wang
                   ` (10 preceding siblings ...)
  2019-06-06  7:02 ` [PATCH v6 11/12] KVM/x86: remove the common handling of the debugctl msr Wei Wang
@ 2019-06-06  7:02 ` Wei Wang
  11 siblings, 0 replies; 13+ messages in thread
From: Wei Wang @ 2019-06-06  7:02 UTC (permalink / raw)
  To: linux-kernel, kvm, pbonzini, ak, peterz
  Cc: kan.liang, mingo, rkrcmar, like.xu, wei.w.wang, jannh,
	arei.gonglei, jmattson

Arch v4 supports streamlined Freeze_LBR_on_PMI. According to the SDM,
the LBR_FRZ bit is set to global status when debugctl.freeze_lbr_on_pmi
has been set and a PMI is generated. The CTR_FRZ bit is set when
debugctl.freeze_perfmon_on_pmi is set and a PMI is generated.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
---
 arch/x86/kvm/pmu.c           | 11 +++++++++--
 arch/x86/kvm/pmu.h           |  1 +
 arch/x86/kvm/vmx/pmu_intel.c | 19 +++++++++++++++++++
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 1e313f3..f5f1f46 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -55,6 +55,13 @@ static void kvm_pmi_trigger_fn(struct irq_work *irq_work)
 	kvm_pmu_deliver_pmi(vcpu);
 }
 
+static void kvm_perf_set_global_status(struct kvm_pmu *pmu, u8 idx)
+{
+	__set_bit(idx, (unsigned long *)&pmu->global_status);
+	if (kvm_x86_ops->pmu_ops->set_global_status)
+		kvm_x86_ops->pmu_ops->set_global_status(pmu, idx);
+}
+
 static void kvm_perf_overflow(struct perf_event *perf_event,
 			      struct perf_sample_data *data,
 			      struct pt_regs *regs)
@@ -64,7 +71,7 @@ static void kvm_perf_overflow(struct perf_event *perf_event,
 
 	if (!test_and_set_bit(pmc->idx,
 			      (unsigned long *)&pmu->reprogram_pmi)) {
-		__set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
+		kvm_perf_set_global_status(pmu, pmc->idx);
 		kvm_make_request(KVM_REQ_PMU, pmc->vcpu);
 	}
 }
@@ -78,7 +85,7 @@ static void kvm_perf_overflow_intr(struct perf_event *perf_event,
 
 	if (!test_and_set_bit(pmc->idx,
 			      (unsigned long *)&pmu->reprogram_pmi)) {
-		__set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
+		kvm_perf_set_global_status(pmu, pmc->idx);
 		kvm_make_request(KVM_REQ_PMU, pmc->vcpu);
 
 		/*
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index cadf91a..408ddc2 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -24,6 +24,7 @@ struct kvm_pmu_ops {
 				    u8 unit_mask);
 	unsigned (*find_fixed_event)(int idx);
 	bool (*pmc_is_enabled)(struct kvm_pmc *pmc);
+	void (*set_global_status)(struct kvm_pmu *pmu, u8 idx);
 	struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx);
 	struct kvm_pmc *(*msr_idx_to_pmc)(struct kvm_vcpu *vcpu, unsigned idx,
 					  u64 *mask);
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index c60f564..62e7bcd 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -421,6 +421,24 @@ static bool intel_pmu_access_lbr_msr(struct kvm_vcpu *vcpu,
 	return ret;
 }
 
+static void intel_pmu_set_global_status(struct kvm_pmu *pmu, u8 idx)
+{
+	u64 guest_debugctl;
+
+	if (pmu->version >= 4) {
+		guest_debugctl = vmcs_read64(GUEST_IA32_DEBUGCTL);
+
+		if ((guest_debugctl & GLOBAL_STATUS_LBRS_FROZEN) ==
+		    DEBUGCTLMSR_FREEZE_LBRS_ON_PMI)
+			__set_bit(GLOBAL_STATUS_LBRS_FROZEN,
+				  (unsigned long *)&pmu->global_status);
+		if ((guest_debugctl & GLOBAL_STATUS_LBRS_FROZEN) ==
+		    DEBUGCTLMSR_FREEZE_PERFMON_ON_PMI)
+			__set_bit(GLOBAL_STATUS_COUNTERS_FROZEN,
+				  (unsigned long *)&pmu->global_status);
+	}
+}
+
 static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -719,6 +737,7 @@ void intel_pmu_disable_save_guest_lbr(struct kvm_vcpu *vcpu)
 struct kvm_pmu_ops intel_pmu_ops = {
 	.find_arch_event = intel_find_arch_event,
 	.find_fixed_event = intel_find_fixed_event,
+	.set_global_status = intel_pmu_set_global_status,
 	.pmc_is_enabled = intel_pmc_is_enabled,
 	.pmc_idx_to_pmc = intel_pmc_idx_to_pmc,
 	.msr_idx_to_pmc = intel_msr_idx_to_pmc,
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 13+ messages in thread
end of thread, other threads:[~2019-06-06  7:45 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-06-06  7:02 [PATCH v6 00/12] Guest LBR Enabling Wei Wang
2019-06-06  7:02 ` [PATCH v6 01/12] perf/x86: fix the variable type of the LBR MSRs Wei Wang
2019-06-06  7:02 ` [PATCH v6 02/12] perf/x86: add a function to get the lbr stack Wei Wang
2019-06-06  7:02 ` [PATCH v6 03/12] KVM/x86: KVM_CAP_X86_GUEST_LBR Wei Wang
2019-06-06  7:02 ` [PATCH v6 04/12] KVM/x86: intel_pmu_lbr_enable Wei Wang
2019-06-06  7:02 ` [PATCH v6 05/12] KVM/x86/vPMU: tweak kvm_pmu_get_msr Wei Wang
2019-06-06  7:02 ` [PATCH v6 06/12] KVM/x86: expose MSR_IA32_PERF_CAPABILITIES to the guest Wei Wang
2019-06-06  7:02 ` [PATCH v6 07/12] perf/x86: no counter allocation support Wei Wang
2019-06-06  7:02 ` [PATCH v6 08/12] KVM/x86/vPMU: Add APIs to support host save/restore the guest lbr stack Wei Wang
2019-06-06  7:02 ` [PATCH v6 09/12] perf/x86: save/restore LBR_SELECT on vCPU switching Wei Wang
2019-06-06  7:02 ` [PATCH v6 10/12] KVM/x86/lbr: lazy save the guest lbr stack Wei Wang
2019-06-06  7:02 ` [PATCH v6 11/12] KVM/x86: remove the common handling of the debugctl msr Wei Wang
2019-06-06  7:02 ` [PATCH v6 12/12] KVM/VMX/vPMU: support to report GLOBAL_STATUS_LBRS_FROZEN Wei Wang

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