KVM: arm64: nv: Add support for FEAT_ATS1A

Handling FEAT_ATS1A (which provides the AT S1E{1,2}A instructions)
is pretty easy, as it is just the usual AT without the permission
check.

This basically amounts to plumbing the instructions in the various
dispatch tables, and handling FEAT_ATS1A being disabled in the
ID registers.
Signed-off-by: Marc Zyngier <maz@kernel.org>

arch/arm64/include/asm/sysreg.h

@@ -673,6 +673,7 @@
 #define OP_AT_S12E1W	sys_insn(AT_Op0, 4, AT_CRn, 8, 5)
 #define OP_AT_S12E0R	sys_insn(AT_Op0, 4, AT_CRn, 8, 6)
 #define OP_AT_S12E0W	sys_insn(AT_Op0, 4, AT_CRn, 8, 7)
+#define OP_AT_S1E2A	sys_insn(AT_Op0, 4, AT_CRn, 9, 2)
 
 /* TLBI instructions */
 #define TLBI_Op0	1

arch/arm64/kvm/at.c

@@ -78,6 +78,7 @@ static enum trans_regime compute_translation_regime(struct kvm_vcpu *vcpu, u32 o
 	switch (op) {
 	case OP_AT_S1E2R:
 	case OP_AT_S1E2W:
+	case OP_AT_S1E2A:
 		return vcpu_el2_e2h_is_set(vcpu) ? TR_EL20 : TR_EL2;
 		break;
 	default:
@@ -852,6 +853,9 @@ static u64 handle_at_slow(struct kvm_vcpu *vcpu, u32 op, u64 vaddr)
 	case OP_AT_S1E0W:
 		perm_fail = !uw;
 		break;
+	case OP_AT_S1E1A:
+	case OP_AT_S1E2A:
+		break;
 	default:
 		BUG();
 	}
@@ -935,6 +939,9 @@ static u64 __kvm_at_s1e01_fast(struct kvm_vcpu *vcpu, u32 op, u64 vaddr)
 	case OP_AT_S1E0W:
 		fail = __kvm_at(OP_AT_S1E0W, vaddr);
 		break;
+	case OP_AT_S1E1A:
+		fail = __kvm_at(OP_AT_S1E1A, vaddr);
+		break;
 	default:
 		WARN_ON_ONCE(1);
 		fail = true;
@@ -1010,6 +1017,9 @@ void __kvm_at_s1e2(struct kvm_vcpu *vcpu, u32 op, u64 vaddr)
 		case OP_AT_S1E2W:
 			fail = __kvm_at(OP_AT_S1E1W, vaddr);
 			break;
+		case OP_AT_S1E2A:
+			fail = __kvm_at(OP_AT_S1E1A, vaddr);
+			break;
 		default:
 			WARN_ON_ONCE(1);
 			fail = true;

arch/arm64/kvm/emulate-nested.c

@@ -786,6 +786,7 @@ static const struct encoding_to_trap_config encoding_to_cgt[] __initconst = {
 	SR_TRAP(OP_AT_S12E1W,		CGT_HCR_NV),
 	SR_TRAP(OP_AT_S12E0R,		CGT_HCR_NV),
 	SR_TRAP(OP_AT_S12E0W,		CGT_HCR_NV),
+	SR_TRAP(OP_AT_S1E2A,		CGT_HCR_NV),
 	SR_TRAP(OP_TLBI_IPAS2E1,	CGT_HCR_NV),
 	SR_TRAP(OP_TLBI_RIPAS2E1,	CGT_HCR_NV),
 	SR_TRAP(OP_TLBI_IPAS2LE1,	CGT_HCR_NV),
@@ -867,6 +868,7 @@ static const struct encoding_to_trap_config encoding_to_cgt[] __initconst = {
 	SR_TRAP(OP_AT_S1E0W, 		CGT_HCR_AT),
 	SR_TRAP(OP_AT_S1E1RP, 		CGT_HCR_AT),
 	SR_TRAP(OP_AT_S1E1WP, 		CGT_HCR_AT),
+	SR_TRAP(OP_AT_S1E1A,		CGT_HCR_AT),
 	SR_TRAP(SYS_ERXPFGF_EL1,	CGT_HCR_nFIEN),
 	SR_TRAP(SYS_ERXPFGCTL_EL1,	CGT_HCR_nFIEN),
 	SR_TRAP(SYS_ERXPFGCDN_EL1,	CGT_HCR_nFIEN),

arch/arm64/kvm/sys_regs.c

@@ -2818,6 +2818,13 @@ static bool handle_at_s1e2(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 {
 	u32 op = sys_insn(p->Op0, p->Op1, p->CRn, p->CRm, p->Op2);
 
+	/* There is no FGT associated with AT S1E2A :-( */
+	if (op == OP_AT_S1E2A &&
+	    !kvm_has_feat(vcpu->kvm, ID_AA64ISAR2_EL1, ATS1A, IMP)) {
+		kvm_inject_undefined(vcpu);
+		return false;
+	}
+
 	__kvm_at_s1e2(vcpu, op, p->regval);
 
 	return true;
@@ -3188,6 +3195,7 @@ static struct sys_reg_desc sys_insn_descs[] = {
 	SYS_INSN(AT_S12E1W, handle_at_s12),
 	SYS_INSN(AT_S12E0R, handle_at_s12),
 	SYS_INSN(AT_S12E0W, handle_at_s12),
+	SYS_INSN(AT_S1E2A, handle_at_s1e2),
 
 	SYS_INSN(TLBI_IPAS2E1IS, handle_ipas2e1is),
 	SYS_INSN(TLBI_RIPAS2E1IS, handle_ripas2e1is),
@@ -4645,6 +4653,9 @@ void kvm_calculate_traps(struct kvm_vcpu *vcpu)
 						HFGITR_EL2_TLBIRVAAE1OS	|
 						HFGITR_EL2_TLBIRVAE1OS);
 
+	if (!kvm_has_feat(kvm, ID_AA64ISAR2_EL1, ATS1A, IMP))
+		kvm->arch.fgu[HFGITR_GROUP] |= HFGITR_EL2_ATS1E1A;
+
 	if (!kvm_has_feat(kvm, ID_AA64MMFR1_EL1, PAN, PAN2))
 		kvm->arch.fgu[HFGITR_GROUP] |= (HFGITR_EL2_ATS1E1RP |
 						HFGITR_EL2_ATS1E1WP);