[RFC PATCH 10/43] powerpc/64s: Always set PMU control registers to frozen/disabled when not in use

[Nicholas Piggin]

KVM PMU management code looks for particular frozen/disabled bits in
the PMU registers so it knows whether it must clear them when coming
out of a guest or not. Setting this up helps KVM make these optimisations
without getting confused. Longer term the better approach might be to
move guest/host PMU switching to the perf subsystem.

Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 arch/powerpc/kernel/cpu_setup_power.c | 4 ++--
 arch/powerpc/kernel/dt_cpu_ftrs.c     | 6 +++---
 arch/powerpc/kvm/book3s_hv.c          | 5 +++++
 arch/powerpc/perf/core-book3s.c       | 7 +++++++
 4 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/cpu_setup_power.c b/arch/powerpc/kernel/cpu_setup_power.c
index a29dc8326622..3dc61e203f37 100644
--- a/arch/powerpc/kernel/cpu_setup_power.c
+++ b/arch/powerpc/kernel/cpu_setup_power.c
@@ -109,7 +109,7 @@ static void init_PMU_HV_ISA207(void)
 static void init_PMU(void)
 {
 	mtspr(SPRN_MMCRA, 0);
-	mtspr(SPRN_MMCR0, 0);
+	mtspr(SPRN_MMCR0, MMCR0_FC);
 	mtspr(SPRN_MMCR1, 0);
 	mtspr(SPRN_MMCR2, 0);
 }
@@ -123,7 +123,7 @@ static void init_PMU_ISA31(void)
 {
 	mtspr(SPRN_MMCR3, 0);
 	mtspr(SPRN_MMCRA, MMCRA_BHRB_DISABLE);
-	mtspr(SPRN_MMCR0, MMCR0_PMCCEXT);
+	mtspr(SPRN_MMCR0, MMCR0_FC | MMCR0_PMCCEXT);
 }
 
 /*
diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c
index 0a6b36b4bda8..06a089fbeaa7 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -353,7 +353,7 @@ static void init_pmu_power8(void)
 	}
 
 	mtspr(SPRN_MMCRA, 0);
-	mtspr(SPRN_MMCR0, 0);
+	mtspr(SPRN_MMCR0, MMCR0_FC);
 	mtspr(SPRN_MMCR1, 0);
 	mtspr(SPRN_MMCR2, 0);
 	mtspr(SPRN_MMCRS, 0);
@@ -392,7 +392,7 @@ static void init_pmu_power9(void)
 		mtspr(SPRN_MMCRC, 0);
 
 	mtspr(SPRN_MMCRA, 0);
-	mtspr(SPRN_MMCR0, 0);
+	mtspr(SPRN_MMCR0, MMCR0_FC);
 	mtspr(SPRN_MMCR1, 0);
 	mtspr(SPRN_MMCR2, 0);
 }
@@ -428,7 +428,7 @@ static void init_pmu_power10(void)
 
 	mtspr(SPRN_MMCR3, 0);
 	mtspr(SPRN_MMCRA, MMCRA_BHRB_DISABLE);
-	mtspr(SPRN_MMCR0, MMCR0_PMCCEXT);
+	mtspr(SPRN_MMCR0, MMCR0_FC | MMCR0_PMCCEXT);
 }
 
 static int __init feat_enable_pmu_power10(struct dt_cpu_feature *f)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 1f30f98b09d1..f7349d150828 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -2593,6 +2593,11 @@ static int kvmppc_core_vcpu_create_hv(struct kvm_vcpu *vcpu)
 #endif
 #endif
 	vcpu->arch.mmcr[0] = MMCR0_FC;
+	if (cpu_has_feature(CPU_FTR_ARCH_31)) {
+		vcpu->arch.mmcr[0] |= MMCR0_PMCCEXT;
+		vcpu->arch.mmcra = MMCRA_BHRB_DISABLE;
+	}
+
 	vcpu->arch.ctrl = CTRL_RUNLATCH;
 	/* default to host PVR, since we can't spoof it */
 	kvmppc_set_pvr_hv(vcpu, mfspr(SPRN_PVR));
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 51622411a7cc..e33b29ec1a65 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -1361,6 +1361,13 @@ static void power_pmu_enable(struct pmu *pmu)
 		goto out;
 
 	if (cpuhw->n_events == 0) {
+		if (cpu_has_feature(CPU_FTR_ARCH_31)) {
+			mtspr(SPRN_MMCRA, MMCRA_BHRB_DISABLE);
+			mtspr(SPRN_MMCR0, MMCR0_FC | MMCR0_PMCCEXT);
+		} else {
+			mtspr(SPRN_MMCRA, 0);
+			mtspr(SPRN_MMCR0, MMCR0_FC);
+		}
 		ppc_set_pmu_inuse(0);
 		goto out;
 	}
-- 
2.23.0