[PATCH 13/17] KVM: arm64: Context switch Partitioned PMU guest registers

[Colton Lewis <coltonlewis@google.com>]

Save and restore newly untrapped registers that will be directly
accessed by the guest when the PMU is partitioned.

* PMEVCNTRn_EL0
* PMCCNTR_EL0
* PMICNTR_EL0
* PMUSERENR_EL0
* PMSELR_EL0
* PMCR_EL0
* PMCNTEN_EL0
* PMINTEN_EL1

If the PMU is not partitioned or MDCR_EL2.TPM is set, all PMU
registers are trapped so return immediately.

Signed-off-by: Colton Lewis <coltonlewis@google.com>
---
 arch/arm64/include/asm/arm_pmuv3.h |  17 ++++-
 arch/arm64/include/asm/kvm_host.h  |   4 +
 arch/arm64/kvm/arm.c               |   2 +
 arch/arm64/kvm/pmu-part.c          | 117 +++++++++++++++++++++++++++++
 4 files changed, 139 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/arm_pmuv3.h b/arch/arm64/include/asm/arm_pmuv3.h
index 5d01ed25c4ef..a00845cffb3f 100644
--- a/arch/arm64/include/asm/arm_pmuv3.h
+++ b/arch/arm64/include/asm/arm_pmuv3.h
@@ -107,6 +107,11 @@ static inline void write_pmcntenset(u64 val)
 	write_sysreg(val, pmcntenset_el0);
 }
 
+static inline u64 read_pmcntenset(void)
+{
+	return read_sysreg(pmcntenset_el0);
+}
+
 static inline void write_pmcntenclr(u64 val)
 {
 	write_sysreg(val, pmcntenclr_el0);
@@ -117,6 +122,11 @@ static inline void write_pmintenset(u64 val)
 	write_sysreg(val, pmintenset_el1);
 }
 
+static inline u64 read_pmintenset(void)
+{
+	return read_sysreg(pmintenset_el1);
+}
+
 static inline void write_pmintenclr(u64 val)
 {
 	write_sysreg(val, pmintenclr_el1);
@@ -162,11 +172,16 @@ static inline u64 read_pmovsclr(void)
 	return read_sysreg(pmovsclr_el0);
 }
 
-static inline void write_pmuserenr(u32 val)
+static inline void write_pmuserenr(u64 val)
 {
 	write_sysreg(val, pmuserenr_el0);
 }
 
+static inline u64 read_pmuserenr(void)
+{
+	return read_sysreg(pmuserenr_el0);
+}
+
 static inline void write_pmuacr(u64 val)
 {
 	write_sysreg_s(val, SYS_PMUACR_EL1);
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 4ea045098bfa..955359f20161 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -453,9 +453,11 @@ enum vcpu_sysreg {
 	PMEVCNTR0_EL0,	/* Event Counter Register (0-30) */
 	PMEVCNTR30_EL0 = PMEVCNTR0_EL0 + 30,
 	PMCCNTR_EL0,	/* Cycle Counter Register */
+	PMICNTR_EL0,	/* Instruction Counter Register */
 	PMEVTYPER0_EL0,	/* Event Type Register (0-30) */
 	PMEVTYPER30_EL0 = PMEVTYPER0_EL0 + 30,
 	PMCCFILTR_EL0,	/* Cycle Count Filter Register */
+	PMICFILTR_EL0,	/* Insturction Count Filter Register */
 	PMCNTENSET_EL0,	/* Count Enable Set Register */
 	PMINTENSET_EL1,	/* Interrupt Enable Set Register */
 	PMOVSSET_EL0,	/* Overflow Flag Status Set Register */
@@ -1713,6 +1715,8 @@ struct kvm_pmu_events *kvm_get_pmu_events(void);
 void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu);
 void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu);
 bool kvm_pmu_overflow_status(struct kvm_vcpu *vcpu);
+void kvm_pmu_load(struct kvm_vcpu *vcpu);
+void kvm_pmu_put(struct kvm_vcpu *vcpu);
 
 /*
  * Updates the vcpu's view of the pmu events for this cpu.
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 3b9c003f2ea6..4a1cc7b72295 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -615,6 +615,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 		kvm_vcpu_load_vhe(vcpu);
 	kvm_arch_vcpu_load_fp(vcpu);
 	kvm_vcpu_pmu_restore_guest(vcpu);
+	kvm_pmu_load(vcpu);
 	if (kvm_arm_is_pvtime_enabled(&vcpu->arch))
 		kvm_make_request(KVM_REQ_RECORD_STEAL, vcpu);
 
@@ -657,6 +658,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 	kvm_timer_vcpu_put(vcpu);
 	kvm_vgic_put(vcpu);
 	kvm_vcpu_pmu_restore_host(vcpu);
+	kvm_pmu_put(vcpu);
 	if (vcpu_has_nv(vcpu))
 		kvm_vcpu_put_hw_mmu(vcpu);
 	kvm_arm_vmid_clear_active();
diff --git a/arch/arm64/kvm/pmu-part.c b/arch/arm64/kvm/pmu-part.c
index 179a4144cfd0..40c72caef34e 100644
--- a/arch/arm64/kvm/pmu-part.c
+++ b/arch/arm64/kvm/pmu-part.c
@@ -8,6 +8,7 @@
 #include <linux/perf/arm_pmu.h>
 #include <linux/perf/arm_pmuv3.h>
 
+#include <asm/kvm_emulate.h>
 #include <asm/kvm_pmu.h>
 #include <asm/arm_pmuv3.h>
 
@@ -202,3 +203,119 @@ void kvm_pmu_host_counters_disable(void)
 	mdcr &= ~MDCR_EL2_HPME;
 	write_sysreg(mdcr, mdcr_el2);
 }
+
+/**
+ * kvm_pmu_load() - Load untrapped PMU registers
+ * @vcpu: Pointer to struct kvm_vcpu
+ *
+ * Load all untrapped PMU registers from the VCPU into the PCPU. Mask
+ * to only bits belonging to guest-reserved counters and leave
+ * host-reserved counters alone in bitmask registers.
+ */
+void kvm_pmu_load(struct kvm_vcpu *vcpu)
+{
+	struct arm_pmu *pmu = vcpu->kvm->arch.arm_pmu;
+	u64 mask = kvm_pmu_guest_counter_mask(pmu);
+	u8 i;
+	u64 val;
+
+	/*
+	 * If the PMU is not partitioned, don't bother.
+	 *
+	 * If we have MDCR_EL2_TPM, every PMU access is trapped which
+	 * implies we are using the emulated PMU instead of direct
+	 * access.
+	 */
+	if (!kvm_pmu_is_partitioned(pmu) || (vcpu->arch.mdcr_el2 & MDCR_EL2_TPM))
+		return;
+
+	for (i = 0; i < pmu->hpmn; i++) {
+		val = __vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i);
+		write_pmevcntrn(i, val);
+	}
+
+	val = __vcpu_sys_reg(vcpu, PMCCNTR_EL0);
+	write_pmccntr(val);
+
+	if (cpus_have_final_cap(ARM64_HAS_PMICNTR)) {
+		val = __vcpu_sys_reg(vcpu, PMICNTR_EL0);
+		write_pmicntr(val);
+	}
+
+	val = __vcpu_sys_reg(vcpu, PMUSERENR_EL0);
+	write_pmuserenr(val);
+
+	val = __vcpu_sys_reg(vcpu, PMSELR_EL0);
+	write_pmselr(val);
+
+	val = __vcpu_sys_reg(vcpu, PMCR_EL0);
+	write_pmcr(val);
+
+	/*
+	 * Loading these registers is tricky because of
+	 * 1. Applying only the bits for guest counters (indicated by mask)
+	 * 2. Setting and clearing are different registers
+	 */
+	val = __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
+	write_pmcntenset(val & mask);
+	write_pmcntenclr(~val & mask);
+
+	val = __vcpu_sys_reg(vcpu, PMINTENSET_EL1);
+	write_pmintenset(val & mask);
+	write_pmintenclr(~val & mask);
+}
+
+/**
+ * kvm_pmu_put() - Put untrapped PMU registers
+ * @vcpu: Pointer to struct kvm_vcpu
+ *
+ * Put all untrapped PMU registers from the VCPU into the PCPU. Mask
+ * to only bits belonging to guest-reserved counters and leave
+ * host-reserved counters alone in bitmask registers.
+ */
+void kvm_pmu_put(struct kvm_vcpu *vcpu)
+{
+	struct arm_pmu *pmu = vcpu->kvm->arch.arm_pmu;
+	u64 mask = kvm_pmu_guest_counter_mask(pmu);
+	u8 i;
+	u64 val;
+
+	/*
+	 * If the PMU is not partitioned, don't bother.
+	 *
+	 * If we have MDCR_EL2_TPM, every PMU access is trapped which
+	 * implies we are using the emulated PMU instead of direct
+	 * access.
+	 */
+	if (!kvm_pmu_is_partitioned(pmu) || (vcpu->arch.mdcr_el2 & MDCR_EL2_TPM))
+		return;
+
+	for (i = 0; i < pmu->hpmn; i++) {
+		val = read_pmevcntrn(i);
+		__vcpu_sys_reg(vcpu, PMEVCNTR0_EL0 + i) = val;
+	}
+
+	val = read_pmccntr();
+	__vcpu_sys_reg(vcpu, PMCCNTR_EL0) = val;
+
+	if (this_cpu_has_cap(ARM64_HAS_PMICNTR)) {
+		val = read_pmicntr();
+		__vcpu_sys_reg(vcpu, PMICNTR_EL0) = val;
+	}
+
+	val = read_pmuserenr();
+	__vcpu_sys_reg(vcpu, PMUSERENR_EL0) = val;
+
+	val = read_pmselr();
+	__vcpu_sys_reg(vcpu, PMSELR_EL0) = val;
+
+	val = read_pmcr();
+	__vcpu_sys_reg(vcpu, PMCR_EL0) = val;
+
+	/* Mask these to only save the guest relevant bits. */
+	val = read_pmcntenset();
+	__vcpu_sys_reg(vcpu, PMCNTENSET_EL0) = val & mask;
+
+	val = read_pmintenset();
+	__vcpu_sys_reg(vcpu, PMINTENSET_EL1) = val & mask;
+}
-- 
2.49.0.1204.g71687c7c1d-goog