From: Shannon Zhao <redacted>

Add access handler which gets host value of PMCEID0 or PMCEID1 when
guest access these registers. Writing action to PMCEID0 or PMCEID1 is
UNDEFINED.

Signed-off-by: Shannon Zhao <redacted>
---
 arch/arm64/kvm/sys_regs.c | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index f9985fc..2552db1 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c

@@ -486,6 +486,25 @@ static bool access_pmselr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	return true;
 }
 
+static bool access_pmceid(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+			  const struct sys_reg_desc *r)
+{
+	u64 pmceid;
+
+	if (p->is_write) {
+		kvm_inject_undefined(vcpu);

+	} else {
+		if (!(p->Op2 & 1))
+			asm volatile("mrs %0, pmceid0_el0\n" : "=r" (pmceid));
+		else
+			asm volatile("mrs %0, pmceid1_el0\n" : "=r" (pmceid));
+
+		p->regval = pmceid;
+	}
+
+	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 */						\

@@ -688,10 +707,10 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	  access_pmselr, reset_unknown, PMSELR_EL0 },
 	/* PMCEID0_EL0 */
 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b110),
-	  trap_raz_wi },
+	  access_pmceid },
 	/* PMCEID1_EL0 */
 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1100), Op2(0b111),
-	  trap_raz_wi },
+	  access_pmceid },
 	/* PMCCNTR_EL0 */
 	{ Op0(0b11), Op1(0b011), CRn(0b1001), CRm(0b1101), Op2(0b000),
 	  trap_raz_wi },

@@ -937,8 +956,8 @@ static const struct sys_reg_desc cp15_regs[] = {
 	{ Op1( 0), CRn( 9), CRm(12), Op2( 2), trap_raz_wi },
 	{ Op1( 0), CRn( 9), CRm(12), Op2( 3), trap_raz_wi },
 	{ Op1( 0), CRn( 9), CRm(12), Op2( 5), access_pmselr },
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 6), trap_raz_wi },
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 7), trap_raz_wi },
+	{ Op1( 0), CRn( 9), CRm(12), Op2( 6), access_pmceid },
+	{ Op1( 0), CRn( 9), CRm(12), Op2( 7), access_pmceid },
 	{ Op1( 0), CRn( 9), CRm(13), Op2( 0), trap_raz_wi },
 	{ Op1( 0), CRn( 9), CRm(13), Op2( 1), trap_raz_wi },
 	{ Op1( 0), CRn( 9), CRm(13), Op2( 2), trap_raz_wi },