[PATCH v2 37/43] arm64: RME: Initialize PMCR.N with number counter supported by RMM

Steven Price
2024-04-12T08:44:46Z

From: Jean-Philippe Brucker <jean-philippe@linaro.org>

Provide an accurate number of available PMU counters to userspace when
setting up a Realm.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Steven Price <steven.price@arm.com>
---
arch/arm64/include/asm/kvm_rme.h | 1 +
arch/arm64/kvm/pmu-emul.c | 3 +++
arch/arm64/kvm/rme.c | 5 +++++
3 files changed, 9 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index 44aa95befc14..9c00bcb018f8 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -88,6 +88,7 @@ struct realm_rec {

int kvm_init_rme(void);
u32 kvm_realm_ipa_limit(void);
+u8 kvm_realm_max_pmu_counters(void);
u64 kvm_realm_reset_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, u64 val);

bool kvm_rme_supports_sve(void);
diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index ce7c8e55d904..39790736f1e2 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -912,6 +912,9 @@ u8 kvm_arm_pmu_get_max_counters(struct kvm *kvm)
{
struct arm_pmu *arm_pmu = kvm->arch.arm_pmu;

+ if (kvm_is_realm(kvm))
+ return kvm_realm_max_pmu_counters();
+
/*
* The arm_pmu->num_events considers the cycle counter as well.
* Ignore that and return only the general-purpose counters.
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 51ac8c3462ea..1bd97e206846 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -271,6 +271,11 @@ u32 kvm_realm_ipa_limit(void)
return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_S2SZ);
}

+u8 kvm_realm_max_pmu_counters(void)
+{
+ return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_PMU_NUM_CTRS);
+}
+
u64 kvm_realm_reset_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, u64 val)
{
u32 bps = u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_NUM_BPS);
--
2.34.1