KVM: arm64: Add TCR2_EL2 to the sysreg arrays

Add the TCR2_EL2 register to the per-vcpu sysreg register array,
the sysreg descriptor array, and advertise it as mapped to TCR2_EL1
for NV purposes.

Access to this register is conditional based on ID_AA64MMFR3_EL1.TCRX
being advertised.

Reviewed-by: Joey Gouly <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Oliver Upton <[email protected]>

Author: Marc Zyngier

arch/arm64/include/asm/kvm_host.h

@@ -499,6 +499,7 @@ enum vcpu_sysreg {
 
 	/* Anything from this can be RES0/RES1 sanitised */
 	MARKER(__SANITISED_REG_START__),
+	TCR2_EL2,	/* Extended Translation Control Register (EL2) */
 
 	/* Any VNCR-capable reg goes after this point */
 	MARKER(__VNCR_START__),

arch/arm64/kvm/sys_regs.c

@@ -134,6 +134,7 @@ static bool get_el2_to_el1_mapping(unsigned int reg,
 		MAPPED_EL2_SYSREG(ESR_EL2,     ESR_EL1,     NULL	     );
 		MAPPED_EL2_SYSREG(FAR_EL2,     FAR_EL1,     NULL	     );
 		MAPPED_EL2_SYSREG(MAIR_EL2,    MAIR_EL1,    NULL	     );
+		MAPPED_EL2_SYSREG(TCR2_EL2,    TCR2_EL1,    NULL	     );
 		MAPPED_EL2_SYSREG(AMAIR_EL2,   AMAIR_EL1,   NULL	     );
 		MAPPED_EL2_SYSREG(ELR_EL2,     ELR_EL1,	    NULL	     );
 		MAPPED_EL2_SYSREG(SPSR_EL2,    SPSR_EL1,    NULL	     );
@@ -452,6 +453,18 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu,
 	return true;
 }
 
+static bool access_tcr2_el2(struct kvm_vcpu *vcpu,
+			    struct sys_reg_params *p,
+			    const struct sys_reg_desc *r)
+{
+	if (!kvm_has_feat(vcpu->kvm, ID_AA64MMFR3_EL1, TCRX, IMP)) {
+		kvm_inject_undefined(vcpu);
+		return false;
+	}
+
+	return access_rw(vcpu, p, r);
+}
+
 static bool access_actlr(struct kvm_vcpu *vcpu,
 			 struct sys_reg_params *p,
 			 const struct sys_reg_desc *r)
@@ -2866,6 +2879,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	EL2_REG(TTBR0_EL2, access_rw, reset_val, 0),
 	EL2_REG(TTBR1_EL2, access_rw, reset_val, 0),
 	EL2_REG(TCR_EL2, access_rw, reset_val, TCR_EL2_RES1),
+	EL2_REG(TCR2_EL2, access_tcr2_el2, reset_val, TCR2_EL2_RES1),
 	EL2_REG_VNCR(VTTBR_EL2, reset_val, 0),
 	EL2_REG_VNCR(VTCR_EL2, reset_val, 0),