[kvm-unit-tests PATCH] x86: Unmask LVTPC on interrupt

From: nadav.amit@gmail.com
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, Nadav Amit <nadav.amit@gmail.com>
Subject: [kvm-unit-tests PATCH] x86: Unmask LVTPC on interrupt
Date: Thu,  2 May 2019 10:41:25 -0700	[thread overview]
Message-ID: <20190502174125.8706-1-nadav.amit@gmail.com> (raw)

From: Nadav Amit <nadav.amit@gmail.com>

According to the SDM: "When a performance monitoring counters interrupt
is generated, the mask bit for its associated LVT entry is set."

Unmask LVTPC on each interrupt by reprogramming it. As the old value is
known, no need for read-modify-write is needed.

Signed-off-by: Nadav Amit <nadav.amit@gmail.com>
---
 x86/pmu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/x86/pmu.c b/x86/pmu.c
index f7b3010..6658fe9 100644
--- a/x86/pmu.c
+++ b/x86/pmu.c
@@ -184,6 +184,7 @@ static void start_event(pmu_counter_t *evt)
 	    wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, ctrl);
     }
     global_enable(evt);
+    apic_write(APIC_LVTPC, PC_VECTOR);
 }
 
 static void stop_event(pmu_counter_t *evt)
-- 
2.17.1

