[PATCH 10/21] KVM: arm64: Set up MDCR_EL2 to handle a Partitioned PMU

[Colton Lewis]

Set up MDCR_EL2 to handle a Partitioned PMU. If partitioned, set the
HPME, HPMD, and HCCD bits. If we have the ability to use Fine Grain
Traps (FEAT_FGT) also, unset the TPM and TPMCR bits that trap all PMU
accesses and set HPMN to the correct number of guest counters so
hardware enforces the right values.

Signed-off-by: Colton Lewis <coltonlewis at google.com>
---
 arch/arm64/kvm/debug.c | 27 ++++++++++++++++++++++++---
 arch/arm64/kvm/pmu.c   |  7 +++++++
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c
index f4d7b12045e8f..c84321277d893 100644
--- a/arch/arm64/kvm/debug.c
+++ b/arch/arm64/kvm/debug.c
@@ -43,14 +43,35 @@ static void kvm_arm_setup_mdcr_el2(struct kvm_vcpu *vcpu)
 	 * This also clears MDCR_EL2_E2PB_MASK and MDCR_EL2_E2TB_MASK
 	 * to disable guest access to the profiling and trace buffers
 	 */
-	vcpu->arch.mdcr_el2 = FIELD_PREP(MDCR_EL2_HPMN,
-					 *host_data_ptr(nr_event_counters));
+
+	vcpu->arch.mdcr_el2 = FIELD_PREP(MDCR_EL2_HPMN, *host_data_ptr(nr_event_counters));
 	vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM |
 				MDCR_EL2_TPMS |
 				MDCR_EL2_TTRF |
 				MDCR_EL2_TPMCR |
 				MDCR_EL2_TDRA |
-				MDCR_EL2_TDOSA);
+				MDCR_EL2_TDOSA |
+				MDCR_EL2_HPME);
+
+	if (kvm_pmu_is_partitioned(vcpu->kvm)) {
+		u8 nr_guest_cntr = vcpu->kvm->arch.nr_pmu_counters;
+
+		vcpu->arch.mdcr_el2 |= (MDCR_EL2_HPMD | MDCR_EL2_HCCD);
+
+		/*
+		 * Take out the coarse grain traps if we are using
+		 * fine grain traps and enforce counter access with
+		 * HPMN.
+		 */
+		if (!vcpu_on_unsupported_cpu(vcpu) &&
+		    cpus_have_final_cap(ARM64_HAS_FGT) &&
+		    (cpus_have_final_cap(ARM64_HAS_HPMN0) || nr_guest_cntr > 0)) {
+			vcpu->arch.mdcr_el2 &= ~(MDCR_EL2_TPM | MDCR_EL2_TPMCR | MDCR_EL2_HPMN);
+			vcpu->arch.mdcr_el2 |= FIELD_PREP(MDCR_EL2_HPMN, nr_guest_cntr);
+		}
+
+
+	}
 
 	/* Is the VM being debugged by userspace? */
 	if (vcpu->guest_debug)
diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c
index 9ad3520417413..55cda8021400a 100644
--- a/arch/arm64/kvm/pmu.c
+++ b/arch/arm64/kvm/pmu.c
@@ -552,6 +552,13 @@ u8 kvm_arm_pmu_get_max_counters(struct kvm *kvm)
 	if (cpus_have_final_cap(ARM64_WORKAROUND_PMUV3_IMPDEF_TRAPS))
 		return 1;
 
+	/*
+	 * If partitioned then we are limited by the max counters in
+	 * the guest partition.
+	 */
+	if (pmu_is_partitioned(arm_pmu))
+		return arm_pmu->max_guest_counters;
+
 	/*
 	 * The arm_pmu->cntr_mask considers the fixed counter(s) as well.
 	 * Ignore those and return only the general-purpose counters.
-- 
2.54.0.1136.gdb2ca164c4-goog