linux-kernel - [PATCH 4/9] perf/x86/intel/pt: add Intel processor trace virtualization call backs

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Date:   Mon, 16 Oct 2017 20:13:10 +0800
From:   Luwei Kang <luwei.kang@...el.com>
To:     kvm@...r.kernel.org
Cc:     pbonzini@...hat.com, rkrcmar@...hat.com, tglx@...utronix.de,
        mingo@...hat.com, hpa@...or.com, x86@...nel.org,
        linux-kernel@...r.kernel.org,
        Chao Peng <chao.p.peng@...ux.intel.com>,
        Luwei Kang <luwei.kang@...el.com>
Subject: [PATCH 4/9] perf/x86/intel/pt: add Intel processor trace virtualization call backs

From: Chao Peng <chao.p.peng@...ux.intel.com>

Add Intel processor trace virtualization call backs to
suppress host event in guest only mode.

Signed-off-by: Chao Peng <chao.p.peng@...ux.intel.com>
Signed-off-by: Luwei Kang <luwei.kang@...el.com>
---
 arch/x86/events/intel/pt.c      | 21 +++++++++++++++++++++
 arch/x86/include/asm/intel_pt.h |  9 +++++++++
 2 files changed, 30 insertions(+)

diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
index a5a7e44..ec54bba 100644
--- a/arch/x86/events/intel/pt.c
+++ b/arch/x86/events/intel/pt.c
@@ -36,6 +36,7 @@
 static DEFINE_PER_CPU(struct pt, pt_ctx);
 
 static struct pt_pmu pt_pmu;
+static struct pt_virt_ops *virt_ops;
 
 /*
  * Capabilities of Intel PT hardware, such as number of address bits or
@@ -177,6 +178,18 @@ static ssize_t pt_cap_show(struct device *cdev,
 	NULL,
 };
 
+void pt_register_virt_ops(struct pt_virt_ops *ops)
+{
+	virt_ops = ops;
+}
+EXPORT_SYMBOL_GPL(pt_register_virt_ops);
+
+void pt_unregister_virt_ops(void)
+{
+	virt_ops = NULL;
+}
+EXPORT_SYMBOL_GPL(pt_unregister_virt_ops);
+
 static int __init pt_pmu_hw_init(void)
 {
 	struct dev_ext_attribute *de_attrs;
@@ -1244,6 +1257,9 @@ void intel_pt_interrupt(void)
 	struct pt_buffer *buf;
 	struct perf_event *event = pt->handle.event;
 
+	if (virt_ops && virt_ops->pmi && virt_ops->pmi())
+		return;
+
 	/*
 	 * There may be a dangling PT bit in the interrupt status register
 	 * after PT has been disabled by pt_event_stop(). Make sure we don't
@@ -1444,6 +1460,11 @@ static void pt_event_destroy(struct perf_event *event)
 
 static int pt_event_init(struct perf_event *event)
 {
+	/* suppress host event in guest only mode */
+	if (virt_ops && virt_ops->get_mode &&
+		virt_ops->get_mode() == PT_MODE_GUEST)
+		return -EPERM;
+
 	if (event->attr.type != pt_pmu.pmu.type)
 		return -ENOENT;
 
diff --git a/arch/x86/include/asm/intel_pt.h b/arch/x86/include/asm/intel_pt.h
index b5dd33c..6a5d475 100644
--- a/arch/x86/include/asm/intel_pt.h
+++ b/arch/x86/include/asm/intel_pt.h
@@ -26,12 +26,21 @@ enum pt_capabilities {
 	PT_CAP_psb_periods,
 };
 
+struct pt_virt_ops {
+	enum pt_mode (*get_mode)(void);
+	bool (*pmi)(void);
+};
+
 #if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_INTEL)
 void cpu_emergency_stop_pt(void);
 extern u32 pt_cap_get(enum pt_capabilities cap);
+extern void pt_register_virt_ops(struct pt_virt_ops *ops);
+extern void pt_unregister_virt_ops(void);
 #else
 static inline void cpu_emergency_stop_pt(void) {}
 static inline u32 pt_cap_get(enum pt_capabilities cap) { return 0; }
+static void pt_register_virt_ops(struct pt_virt_ops *ops) { }
+static void pt_unregister_virt_ops(void) { }
 #endif
 
 #endif /* _ASM_X86_INTEL_PT_H */
-- 
1.8.3.1