1 files changed, 14 insertions, 15 deletions

diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
index b4aa8daa4773..fd4670a6694e 100644
--- a/arch/x86/events/intel/pt.c
+++ b/arch/x86/events/intel/pt.c
@@ -416,7 +416,7 @@ static bool pt_event_valid(struct perf_event *event)
 static void pt_config_start(struct perf_event *event)
 {
 	struct pt *pt = this_cpu_ptr(&pt_ctx);
-	u64 ctl = event->hw.config;
+	u64 ctl = event->hw.aux_config;
 
 	ctl |= RTIT_CTL_TRACEEN;
 	if (READ_ONCE(pt->vmx_on))
@@ -424,7 +424,7 @@ static void pt_config_start(struct perf_event *event)
 	else
 		wrmsrl(MSR_IA32_RTIT_CTL, ctl);
 
-	WRITE_ONCE(event->hw.config, ctl);
+	WRITE_ONCE(event->hw.aux_config, ctl);
 }
 
 /* Address ranges and their corresponding msr configuration registers */
@@ -503,7 +503,7 @@ static void pt_config(struct perf_event *event)
 	u64 reg;
 
 	/* First round: clear STATUS, in particular the PSB byte counter. */
-	if (!event->hw.config) {
+	if (!event->hw.aux_config) {
 		perf_event_itrace_started(event);
 		wrmsrl(MSR_IA32_RTIT_STATUS, 0);
 	}
@@ -533,14 +533,14 @@ static void pt_config(struct perf_event *event)
 
 	reg |= (event->attr.config & PT_CONFIG_MASK);
 
-	event->hw.config = reg;
+	event->hw.aux_config = reg;
 	pt_config_start(event);
 }
 
 static void pt_config_stop(struct perf_event *event)
 {
 	struct pt *pt = this_cpu_ptr(&pt_ctx);
-	u64 ctl = READ_ONCE(event->hw.config);
+	u64 ctl = READ_ONCE(event->hw.aux_config);
 
 	/* may be already stopped by a PMI */
 	if (!(ctl & RTIT_CTL_TRACEEN))
@@ -550,7 +550,7 @@ static void pt_config_stop(struct perf_event *event)
 	if (!READ_ONCE(pt->vmx_on))
 		wrmsrl(MSR_IA32_RTIT_CTL, ctl);
 
-	WRITE_ONCE(event->hw.config, ctl);
+	WRITE_ONCE(event->hw.aux_config, ctl);
 
 	/*
 	 * A wrmsr that disables trace generation serializes other PT
@@ -1557,7 +1557,7 @@ void intel_pt_handle_vmx(int on)
 
 	/* Turn PTs back on */
 	if (!on && event)
-		wrmsrl(MSR_IA32_RTIT_CTL, event->hw.config);
+		wrmsrl(MSR_IA32_RTIT_CTL, event->hw.aux_config);
 
 	local_irq_restore(flags);
 }
@@ -1606,6 +1606,7 @@ static void pt_event_stop(struct perf_event *event, int mode)
 	 * see comment in intel_pt_interrupt().
 	 */
 	WRITE_ONCE(pt->handle_nmi, 0);
+	barrier();
 
 	pt_config_stop(event);
 
@@ -1657,11 +1658,10 @@ static long pt_event_snapshot_aux(struct perf_event *event,
 		return 0;
 
 	/*
-	 * Here, handle_nmi tells us if the tracing is on
+	 * There is no PT interrupt in this mode, so stop the trace and it will
+	 * remain stopped while the buffer is copied.
 	 */
-	if (READ_ONCE(pt->handle_nmi))
-		pt_config_stop(event);
-
+	pt_config_stop(event);
 	pt_read_offset(buf);
 	pt_update_head(pt);
 
@@ -1673,11 +1673,10 @@ static long pt_event_snapshot_aux(struct perf_event *event,
 	ret = perf_output_copy_aux(&pt->handle, handle, from, to);
 
 	/*
-	 * If the tracing was on when we turned up, restart it.
-	 * Compiler barrier not needed as we couldn't have been
-	 * preempted by anything that touches pt->handle_nmi.
+	 * Here, handle_nmi tells us if the tracing was on.
+	 * If the tracing was on, restart it.
 	 */
-	if (pt->handle_nmi)
+	if (READ_ONCE(pt->handle_nmi))
 		pt_config_start(event);
 
 	return ret;