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-rw-r--r--arch/arm64/include/asm/kvm_host.h3
-rw-r--r--arch/arm64/kvm/pmu-emul.c21
-rw-r--r--arch/arm64/kvm/sys_regs.c28
-rw-r--r--include/kvm/arm_pmu.h6
4 files changed, 43 insertions, 15 deletions
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index af06ccb7ee34..0fe9cc9dc836 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -257,6 +257,9 @@ struct kvm_arch {
cpumask_var_t supported_cpus;
+ /* PMCR_EL0.N value for the guest */
+ u8 pmcr_n;
+
/* Hypercall features firmware registers' descriptor */
struct kvm_smccc_features smccc_feat;
struct maple_tree smccc_filter;
diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index 6337ba6f7941..6d4763d7308f 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -873,11 +873,27 @@ static bool pmu_irq_is_valid(struct kvm *kvm, int irq)
return true;
}
+/**
+ * kvm_arm_pmu_get_max_counters - Return the max number of PMU counters.
+ * @kvm: The kvm pointer
+ */
+u8 kvm_arm_pmu_get_max_counters(struct kvm *kvm)
+{
+ struct arm_pmu *arm_pmu = kvm->arch.arm_pmu;
+
+ /*
+ * The arm_pmu->num_events considers the cycle counter as well.
+ * Ignore that and return only the general-purpose counters.
+ */
+ return arm_pmu->num_events - 1;
+}
+
static void kvm_arm_set_pmu(struct kvm *kvm, struct arm_pmu *arm_pmu)
{
lockdep_assert_held(&kvm->arch.config_lock);
kvm->arch.arm_pmu = arm_pmu;
+ kvm->arch.pmcr_n = kvm_arm_pmu_get_max_counters(kvm);
}
/**
@@ -1091,5 +1107,8 @@ u8 kvm_arm_pmu_get_pmuver_limit(void)
*/
u64 kvm_vcpu_read_pmcr(struct kvm_vcpu *vcpu)
{
- return __vcpu_sys_reg(vcpu, PMCR_EL0);
+ u64 pmcr = __vcpu_sys_reg(vcpu, PMCR_EL0) &
+ ~(ARMV8_PMU_PMCR_N_MASK << ARMV8_PMU_PMCR_N_SHIFT);
+
+ return pmcr | ((u64)vcpu->kvm->arch.pmcr_n << ARMV8_PMU_PMCR_N_SHIFT);
}
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index d490cd903e2b..6dcfac15fe49 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -721,12 +721,7 @@ static u64 reset_pmu_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
u64 n, mask = BIT(ARMV8_PMU_CYCLE_IDX);
- /* No PMU available, any PMU reg may UNDEF... */
- if (!kvm_arm_support_pmu_v3())
- return 0;
-
- n = read_sysreg(pmcr_el0) >> ARMV8_PMU_PMCR_N_SHIFT;
- n &= ARMV8_PMU_PMCR_N_MASK;
+ n = vcpu->kvm->arch.pmcr_n;
if (n)
mask |= GENMASK(n - 1, 0);
@@ -762,17 +757,15 @@ static u64 reset_pmselr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
static u64 reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
{
- u64 pmcr;
+ u64 pmcr = 0;
- /* No PMU available, PMCR_EL0 may UNDEF... */
- if (!kvm_arm_support_pmu_v3())
- return 0;
-
- /* Only preserve PMCR_EL0.N, and reset the rest to 0 */
- pmcr = read_sysreg(pmcr_el0) & (ARMV8_PMU_PMCR_N_MASK << ARMV8_PMU_PMCR_N_SHIFT);
if (!kvm_supports_32bit_el0())
pmcr |= ARMV8_PMU_PMCR_LC;
+ /*
+ * The value of PMCR.N field is included when the
+ * vCPU register is read via kvm_vcpu_read_pmcr().
+ */
__vcpu_sys_reg(vcpu, r->reg) = pmcr;
return __vcpu_sys_reg(vcpu, r->reg);
@@ -1103,6 +1096,13 @@ static bool access_pmuserenr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
return true;
}
+static int get_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+ u64 *val)
+{
+ *val = kvm_vcpu_read_pmcr(vcpu);
+ return 0;
+}
+
/* Silly macro to expand the DBG{BCR,BVR,WVR,WCR}n_EL1 registers in one go */
#define DBG_BCR_BVR_WCR_WVR_EL1(n) \
{ SYS_DESC(SYS_DBGBVRn_EL1(n)), \
@@ -2167,7 +2167,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_SVCR), undef_access },
{ PMU_SYS_REG(PMCR_EL0), .access = access_pmcr,
- .reset = reset_pmcr, .reg = PMCR_EL0 },
+ .reset = reset_pmcr, .reg = PMCR_EL0, .get_user = get_pmcr },
{ PMU_SYS_REG(PMCNTENSET_EL0),
.access = access_pmcnten, .reg = PMCNTENSET_EL0 },
{ PMU_SYS_REG(PMCNTENCLR_EL0),
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index c6a5e49b850a..96e15f4bb18c 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -102,6 +102,7 @@ void kvm_vcpu_pmu_resync_el0(void);
u8 kvm_arm_pmu_get_pmuver_limit(void);
int kvm_arm_set_default_pmu(struct kvm *kvm);
+u8 kvm_arm_pmu_get_max_counters(struct kvm *kvm);
u64 kvm_vcpu_read_pmcr(struct kvm_vcpu *vcpu);
#else
@@ -181,6 +182,11 @@ static inline int kvm_arm_set_default_pmu(struct kvm *kvm)
return -ENODEV;
}
+static inline u8 kvm_arm_pmu_get_max_counters(struct kvm *kvm)
+{
+ return 0;
+}
+
static inline u64 kvm_vcpu_read_pmcr(struct kvm_vcpu *vcpu)
{
return 0;