[PATCH v8 05/13] KVM: arm64: Add {get,set}_user for PM{C,I}NTEN{SET,CLR}, PMOVS{SET,CLR}

[Raghavendra Rao Ananta]

For unimplemented counters, the bits in PM{C,I}NTEN{SET,CLR} and
PMOVS{SET,CLR} registers are expected to RAZ. To honor this,
explicitly implement the {get,set}_user functions for these
registers to mask out unimplemented counters for userspace reads
and writes.

Signed-off-by: Raghavendra Rao Ananta <rananta at google.com>
---
 arch/arm64/kvm/sys_regs.c | 91 ++++++++++++++++++++++++++++++++++++---
 1 file changed, 85 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index faf97878dfbbb..2e5d497596ef8 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -987,6 +987,45 @@ static bool access_pmu_evtyper(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	return true;
 }
 
+static void set_pmreg_for_valid_counters(struct kvm_vcpu *vcpu,
+					  u64 reg, u64 val, bool set)
+{
+	struct kvm *kvm = vcpu->kvm;
+
+	mutex_lock(&kvm->arch.config_lock);
+
+	/* Make the register immutable once the VM has started running */
+	if (kvm_vm_has_ran_once(kvm)) {
+		mutex_unlock(&kvm->arch.config_lock);
+		return;
+	}
+
+	val &= kvm_pmu_valid_counter_mask(vcpu);
+	mutex_unlock(&kvm->arch.config_lock);
+
+	if (set)
+		__vcpu_sys_reg(vcpu, reg) |= val;
+	else
+		__vcpu_sys_reg(vcpu, reg) &= ~val;
+}
+
+static int get_pmcnten(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			u64 *val)
+{
+	u64 mask = kvm_pmu_valid_counter_mask(vcpu);
+
+	*val = __vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & mask;
+	return 0;
+}
+
+static int set_pmcnten(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			u64 val)
+{
+	/* r->Op2 & 0x1: true for PMCNTENSET_EL0, else PMCNTENCLR_EL0 */
+	set_pmreg_for_valid_counters(vcpu, PMCNTENSET_EL0, val, r->Op2 & 0x1);
+	return 0;
+}
+
 static bool access_pmcnten(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 			   const struct sys_reg_desc *r)
 {
@@ -1015,6 +1054,23 @@ static bool access_pmcnten(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	return true;
 }
 
+static int get_pminten(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			u64 *val)
+{
+	u64 mask = kvm_pmu_valid_counter_mask(vcpu);
+
+	*val = __vcpu_sys_reg(vcpu, PMINTENSET_EL1) & mask;
+	return 0;
+}
+
+static int set_pminten(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+			u64 val)
+{
+	/* r->Op2 & 0x1: true for PMINTENSET_EL1, else PMINTENCLR_EL1 */
+	set_pmreg_for_valid_counters(vcpu, PMINTENSET_EL1, val, r->Op2 & 0x1);
+	return 0;
+}
+
 static bool access_pminten(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 			   const struct sys_reg_desc *r)
 {
@@ -1039,6 +1095,23 @@ static bool access_pminten(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	return true;
 }
 
+static int set_pmovs(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+		      u64 val)
+{
+	/* r->CRm & 0x2: true for PMOVSSET_EL0, else PMOVSCLR_EL0 */
+	set_pmreg_for_valid_counters(vcpu, PMOVSSET_EL0, val, r->CRm & 0x2);
+	return 0;
+}
+
+static int get_pmovs(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
+		      u64 *val)
+{
+	u64 mask = kvm_pmu_valid_counter_mask(vcpu);
+
+	*val = __vcpu_sys_reg(vcpu, PMOVSSET_EL0) & mask;
+	return 0;
+}
+
 static bool access_pmovs(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 			 const struct sys_reg_desc *r)
 {
@@ -2184,9 +2257,11 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	/* PMBIDR_EL1 is not trapped */
 
 	{ PMU_SYS_REG(PMINTENSET_EL1),
-	  .access = access_pminten, .reg = PMINTENSET_EL1 },
+	  .access = access_pminten, .reg = PMINTENSET_EL1,
+	  .get_user = get_pminten, .set_user = set_pminten },
 	{ PMU_SYS_REG(PMINTENCLR_EL1),
-	  .access = access_pminten, .reg = PMINTENSET_EL1 },
+	  .access = access_pminten, .reg = PMINTENSET_EL1,
+	  .get_user = get_pminten, .set_user = set_pminten },
 	{ SYS_DESC(SYS_PMMIR_EL1), trap_raz_wi },
 
 	{ SYS_DESC(SYS_MAIR_EL1), access_vm_reg, reset_unknown, MAIR_EL1 },
@@ -2237,11 +2312,14 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	{ PMU_SYS_REG(PMCR_EL0), .access = access_pmcr,
 	  .reset = reset_pmcr, .reg = PMCR_EL0, .get_user = get_pmcr },
 	{ PMU_SYS_REG(PMCNTENSET_EL0),
-	  .access = access_pmcnten, .reg = PMCNTENSET_EL0 },
+	  .access = access_pmcnten, .reg = PMCNTENSET_EL0,
+	  .get_user = get_pmcnten, .set_user = set_pmcnten },
 	{ PMU_SYS_REG(PMCNTENCLR_EL0),
-	  .access = access_pmcnten, .reg = PMCNTENSET_EL0 },
+	  .access = access_pmcnten, .reg = PMCNTENSET_EL0,
+	  .get_user = get_pmcnten, .set_user = set_pmcnten },
 	{ PMU_SYS_REG(PMOVSCLR_EL0),
-	  .access = access_pmovs, .reg = PMOVSSET_EL0 },
+	  .access = access_pmovs, .reg = PMOVSSET_EL0,
+	  .get_user = get_pmovs, .set_user = set_pmovs },
 	/*
 	 * PM_SWINC_EL0 is exposed to userspace as RAZ/WI, as it was
 	 * previously (and pointlessly) advertised in the past...
@@ -2269,7 +2347,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	{ PMU_SYS_REG(PMUSERENR_EL0), .access = access_pmuserenr,
 	  .reset = reset_val, .reg = PMUSERENR_EL0, .val = 0 },
 	{ PMU_SYS_REG(PMOVSSET_EL0),
-	  .access = access_pmovs, .reg = PMOVSSET_EL0 },
+	  .access = access_pmovs, .reg = PMOVSSET_EL0,
+	  .get_user = get_pmovs, .set_user = set_pmovs },
 
 	{ SYS_DESC(SYS_TPIDR_EL0), NULL, reset_unknown, TPIDR_EL0 },
 	{ SYS_DESC(SYS_TPIDRRO_EL0), NULL, reset_unknown, TPIDRRO_EL0 },
-- 
2.42.0.655.g421f12c284-goog