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From: Wei Wang <wei.w.wang@intel.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	pbonzini@redhat.com, ak@linux.intel.com, peterz@infradead.org
Cc: kan.liang@intel.com, mingo@redhat.com, rkrcmar@redhat.com,
	like.xu@intel.com, wei.w.wang@intel.com, jannh@google.com,
	arei.gonglei@huawei.com, jmattson@google.com
Subject: [PATCH v5 02/12] perf/x86: add a function to get the lbr stack
Date: Thu, 14 Feb 2019 17:06:04 +0800	[thread overview]
Message-ID: <1550135174-5423-3-git-send-email-wei.w.wang@intel.com> (raw)
In-Reply-To: <1550135174-5423-1-git-send-email-wei.w.wang@intel.com>

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 c88ed39..594a91b 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -1277,3 +1277,26 @@ 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 8bdf749..2f82795 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -275,7 +275,16 @@ 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);
@@ -286,6 +295,11 @@ 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


  parent reply	other threads:[~2019-02-14  9:44 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-14  9:06 [PATCH v5 00/12] Guest LBR Enabling Wei Wang
2019-02-14  9:06 ` [PATCH v5 01/12] perf/x86: fix the variable type of the LBR MSRs Wei Wang
2019-02-14  9:06 ` Wei Wang [this message]
2019-02-14  9:06 ` [PATCH v5 03/12] KVM/x86: KVM_CAP_X86_GUEST_LBR Wei Wang
2019-02-14 16:21   ` Andi Kleen
2019-02-14  9:06 ` [PATCH v5 04/12] KVM/x86: intel_pmu_lbr_enable Wei Wang
2019-02-14  9:06 ` [PATCH v5 05/12] KVM/x86/vPMU: tweak kvm_pmu_get_msr Wei Wang
2019-02-14  9:06 ` [PATCH v5 06/12] KVM/x86: expose MSR_IA32_PERF_CAPABILITIES to the guest Wei Wang
2019-02-14  9:06 ` [PATCH v5 07/12] perf/x86: no counter allocation support Wei Wang
2019-02-14 16:26   ` Andi Kleen
2019-02-15  8:49     ` Wang, Wei W
2019-02-14  9:06 ` [PATCH v5 08/12] KVM/x86/vPMU: Add APIs to support host save/restore the guest lbr stack Wei Wang
2019-02-14  9:06 ` [PATCH v5 09/12] perf/x86: save/restore LBR_SELECT on vCPU switching Wei Wang
2019-02-14  9:06 ` [PATCH v5 10/12] KVM/x86/lbr: lazy save the guest lbr stack Wei Wang
2019-02-15  1:49   ` Like Xu
2019-02-15  9:00     ` Wang, Wei W
2019-02-14  9:06 ` [PATCH v5 11/12] KVM/x86: remove the common handling of the debugctl msr Wei Wang
2019-02-14  9:06 ` [PATCH v5 12/12] KVM/VMX/vPMU: support to report GLOBAL_STATUS_LBRS_FROZEN Wei Wang
2019-02-14 16:31   ` Andi Kleen
2019-02-15  8:56     ` Wang, Wei W
2019-02-15 13:10       ` Andi Kleen
2019-02-18  1:59         ` Wei Wang

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