KVM: arm64: Bump up the default KVM sanitised debug version to v8p8

Since ID_AA64DFR0_EL1 and ID_DFR0_EL1 are now writable from userspace,
it is safe to bump up the default KVM sanitised debug version to v8p8.
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231003230408.3405722-6-oliver.upton@linux.devSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

arch/arm64/kvm/sys_regs.c

@@ -1496,8 +1496,7 @@ static u64 read_sanitised_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
 {
 	u64 val = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1);
 
-	/* Limit debug to ARMv8.0 */
-	val = ID_REG_LIMIT_FIELD_ENUM(val, ID_AA64DFR0_EL1, DebugVer, IMP);
+	val = ID_REG_LIMIT_FIELD_ENUM(val, ID_AA64DFR0_EL1, DebugVer, V8P8);
 
 	/*
 	 * Only initialize the PMU version if the vCPU was configured with one.
@@ -1557,6 +1556,8 @@ static u64 read_sanitised_id_dfr0_el1(struct kvm_vcpu *vcpu,
 	if (kvm_vcpu_has_pmu(vcpu))
 		val |= SYS_FIELD_PREP(ID_DFR0_EL1, PerfMon, perfmon);
 
+	val = ID_REG_LIMIT_FIELD_ENUM(val, ID_DFR0_EL1, CopDbg, Debugv8p8);
+
 	return val;
 }
 
@@ -2013,7 +2014,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	  .set_user = set_id_dfr0_el1,
 	  .visibility = aa32_id_visibility,
 	  .reset = read_sanitised_id_dfr0_el1,
-	  .val = ID_DFR0_EL1_PerfMon_MASK, },
+	  .val = ID_DFR0_EL1_PerfMon_MASK |
+		 ID_DFR0_EL1_CopDbg_MASK, },
 	ID_HIDDEN(ID_AFR0_EL1),
 	AA32_ID_SANITISED(ID_MMFR0_EL1),
 	AA32_ID_SANITISED(ID_MMFR1_EL1),
@@ -2062,7 +2064,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	  .get_user = get_id_reg,
 	  .set_user = set_id_aa64dfr0_el1,
 	  .reset = read_sanitised_id_aa64dfr0_el1,
-	  .val = ID_AA64DFR0_EL1_PMUVer_MASK, },
+	  .val = ID_AA64DFR0_EL1_PMUVer_MASK |
+		 ID_AA64DFR0_EL1_DebugVer_MASK, },
 	ID_SANITISED(ID_AA64DFR1_EL1),
 	ID_UNALLOCATED(5,2),
 	ID_UNALLOCATED(5,3),