KVM: arm64: PMU: Add a helper to read a vCPU's PMCR_EL0

Add a helper to read a vCPU's PMCR_EL0, and use it whenever KVM
reads a vCPU's PMCR_EL0.

Currently, the PMCR_EL0 value is tracked per vCPU. The following
patches will make (only) PMCR_EL0.N track per guest. Having the
new helper will be useful to combine the PMCR_EL0.N field
(tracked per guest) and the other fields (tracked per vCPU)
to provide the value of PMCR_EL0.

No functional change intended.

Reviewed-by: Sebastian Ott <sebott@redhat.com>
Signed-off-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231020214053.2144305-4-rananta@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 0771c42..624e62b 100644 (file)
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -801,8 +801,7 @@ static int check_vcpu_requests(struct kvm_vcpu *vcpu)
                }
 
                if (kvm_check_request(KVM_REQ_RELOAD_PMU, vcpu))
-                       kvm_pmu_handle_pmcr(vcpu,
-                                           __vcpu_sys_reg(vcpu, PMCR_EL0));
+                       kvm_pmu_handle_pmcr(vcpu, kvm_vcpu_read_pmcr(vcpu));
 
                if (kvm_check_request(KVM_REQ_RESYNC_PMU_EL0, vcpu))
                        kvm_vcpu_pmu_restore_guest(vcpu);

diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index 1eb0276..6337ba6 100644 (file)
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -72,7 +72,7 @@ static bool kvm_pmc_is_64bit(struct kvm_pmc *pmc)
 
 static bool kvm_pmc_has_64bit_overflow(struct kvm_pmc *pmc)
 {
-       u64 val = __vcpu_sys_reg(kvm_pmc_to_vcpu(pmc), PMCR_EL0);
+       u64 val = kvm_vcpu_read_pmcr(kvm_pmc_to_vcpu(pmc));
 
        return (pmc->idx < ARMV8_PMU_CYCLE_IDX && (val & ARMV8_PMU_PMCR_LP)) ||
               (pmc->idx == ARMV8_PMU_CYCLE_IDX && (val & ARMV8_PMU_PMCR_LC));
@@ -250,7 +250,7 @@ void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu)
 
 u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu)
 {
-       u64 val = __vcpu_sys_reg(vcpu, PMCR_EL0) >> ARMV8_PMU_PMCR_N_SHIFT;
+       u64 val = kvm_vcpu_read_pmcr(vcpu) >> ARMV8_PMU_PMCR_N_SHIFT;
 
        val &= ARMV8_PMU_PMCR_N_MASK;
        if (val == 0)
@@ -272,7 +272,7 @@ void kvm_pmu_enable_counter_mask(struct kvm_vcpu *vcpu, u64 val)
        if (!kvm_vcpu_has_pmu(vcpu))
                return;
 
-       if (!(__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E) || !val)
+       if (!(kvm_vcpu_read_pmcr(vcpu) & ARMV8_PMU_PMCR_E) || !val)
                return;
 
        for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) {
@@ -324,7 +324,7 @@ static u64 kvm_pmu_overflow_status(struct kvm_vcpu *vcpu)
 {
        u64 reg = 0;
 
-       if ((__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E)) {
+       if ((kvm_vcpu_read_pmcr(vcpu) & ARMV8_PMU_PMCR_E)) {
                reg = __vcpu_sys_reg(vcpu, PMOVSSET_EL0);
                reg &= __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
                reg &= __vcpu_sys_reg(vcpu, PMINTENSET_EL1);
@@ -426,7 +426,7 @@ static void kvm_pmu_counter_increment(struct kvm_vcpu *vcpu,
 {
        int i;
 
-       if (!(__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E))
+       if (!(kvm_vcpu_read_pmcr(vcpu) & ARMV8_PMU_PMCR_E))
                return;
 
        /* Weed out disabled counters */
@@ -569,7 +569,7 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
 static bool kvm_pmu_counter_is_enabled(struct kvm_pmc *pmc)
 {
        struct kvm_vcpu *vcpu = kvm_pmc_to_vcpu(pmc);
-       return (__vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E) &&
+       return (kvm_vcpu_read_pmcr(vcpu) & ARMV8_PMU_PMCR_E) &&
               (__vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & BIT(pmc->idx));
 }
 
@@ -1084,3 +1084,12 @@ u8 kvm_arm_pmu_get_pmuver_limit(void)
                                              ID_AA64DFR0_EL1_PMUVer_V3P5);
        return FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), tmp);
 }
+
+/**
+ * kvm_vcpu_read_pmcr - Read PMCR_EL0 register for the vCPU
+ * @vcpu: The vcpu pointer
+ */
+u64 kvm_vcpu_read_pmcr(struct kvm_vcpu *vcpu)
+{
+       return __vcpu_sys_reg(vcpu, PMCR_EL0);
+}

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index e92ec81..d490cd9 100644 (file)
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -822,7 +822,7 @@ static bool access_pmcr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
                 * Only update writeable bits of PMCR (continuing into
                 * kvm_pmu_handle_pmcr() as well)
                 */
-               val = __vcpu_sys_reg(vcpu, PMCR_EL0);
+               val = kvm_vcpu_read_pmcr(vcpu);
                val &= ~ARMV8_PMU_PMCR_MASK;
                val |= p->regval & ARMV8_PMU_PMCR_MASK;
                if (!kvm_supports_32bit_el0())
@@ -830,7 +830,7 @@ static bool access_pmcr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
                kvm_pmu_handle_pmcr(vcpu, val);
        } else {
                /* PMCR.P & PMCR.C are RAZ */
-               val = __vcpu_sys_reg(vcpu, PMCR_EL0)
+               val = kvm_vcpu_read_pmcr(vcpu)
                      & ~(ARMV8_PMU_PMCR_P | ARMV8_PMU_PMCR_C);
                p->regval = val;
        }
@@ -879,7 +879,7 @@ static bool pmu_counter_idx_valid(struct kvm_vcpu *vcpu, u64 idx)
 {
        u64 pmcr, val;
 
-       pmcr = __vcpu_sys_reg(vcpu, PMCR_EL0);
+       pmcr = kvm_vcpu_read_pmcr(vcpu);
        val = (pmcr >> ARMV8_PMU_PMCR_N_SHIFT) & ARMV8_PMU_PMCR_N_MASK;
        if (idx >= val && idx != ARMV8_PMU_CYCLE_IDX) {
                kvm_inject_undefined(vcpu);

diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index b80c75d..c6a5e49 100644 (file)
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -103,6 +103,7 @@ void kvm_vcpu_pmu_resync_el0(void);
 u8 kvm_arm_pmu_get_pmuver_limit(void);
 int kvm_arm_set_default_pmu(struct kvm *kvm);
 
+u64 kvm_vcpu_read_pmcr(struct kvm_vcpu *vcpu);
 #else
 struct kvm_pmu {
 };
@@ -180,6 +181,11 @@ static inline int kvm_arm_set_default_pmu(struct kvm *kvm)
        return -ENODEV;
 }
 
+static inline u64 kvm_vcpu_read_pmcr(struct kvm_vcpu *vcpu)
+{
+       return 0;
+}
+
 #endif
 
 #endif