From: Shannon Zhao <redacted>

Since the reset value of PMUSERENR_EL0 is UNKNOWN, use reset_unknown for
its reset handler. Add access handler which emulates writing and reading
PMUSERENR_EL0 register.

Signed-off-by: Shannon Zhao <redacted>
---
 arch/arm64/kvm/sys_regs.c | 15 ++++++++++++++-
 include/kvm/arm_pmu.h     |  1 +
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index ec80937..d5984d0 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c

@@ -522,6 +522,19 @@ static bool access_pmovsclr(struct kvm_vcpu *vcpu,
 	return true;
 }
 
+/* PMUSERENR_EL0 accessor. */
+static bool access_pmuserenr(struct kvm_vcpu *vcpu,
+			     const struct sys_reg_params *p,
+			     const struct sys_reg_desc *r)
+{
+	if (p->is_write)
+		vcpu->arch.pmu.user_enable |= *vcpu_reg(vcpu, p->Rt);
+	else
+		*vcpu_reg(vcpu, p->Rt) = vcpu->arch.pmu.user_enable;
+
+	return true;
+}
+
 /* Silly macro to expand the DBG{BCR,BVR,WVR,WCR}n_EL1 registers in one go */
 #define DBG_BCR_BVR_WCR_WVR_EL1(n)					\
 	/* DBGBVRn_EL1 */						\

@@ -746,7 +759,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	  access_pmxevcntr, reset_unknown, PMXEVCNTR_EL0 },
 	/* PMUSERENR_EL0 */
 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1110), Op2(0b000),
-	  trap_raz_wi },
+	  access_pmuserenr, reset_unknown, PMUSERENR_EL0 },
 	/* PMOVSSET_EL0 */
 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1110), Op2(0b011),
 	  access_pmovsset, reset_unknown, PMOVSSET_EL0 },

diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index dee8356..4f3d8a6 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h

@@ -39,6 +39,7 @@ struct kvm_pmu {
 	/* IRQ pending flag */
 	bool irq_pending;
 	struct irq_work irq_work;
+	u32 user_enable;