diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 297ad5e47a..408d749b7a 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -1201,6 +1201,7 @@ void pmu_init(ARMCPU *cpu);
 #define PSTATE_BTYPE (3U << 10)
 #define PSTATE_IL (1U << 20)
 #define PSTATE_SS (1U << 21)
+#define PSTATE_TCO (1U << 25)
 #define PSTATE_V (1U << 28)
 #define PSTATE_C (1U << 29)
 #define PSTATE_Z (1U << 30)
@@ -3196,6 +3197,7 @@ FIELD(TBFLAG_A64, PAUTH_ACTIVE, 8, 1)
 FIELD(TBFLAG_A64, BT, 9, 1)
 FIELD(TBFLAG_A64, BTYPE, 10, 2)
 FIELD(TBFLAG_A64, TBID, 12, 2)
+FIELD(TBFLAG_A64, MTE_ACTIVE, 14, 1)
 
 static inline bool bswap_code(bool sctlr_b)
 {
@@ -3598,6 +3600,16 @@ static inline bool isar_feature_aa64_bti(const ARMISARegisters *id)
     return FIELD_EX64(id->id_aa64pfr1, ID_AA64PFR1, BT) != 0;
 }
 
+static inline bool isar_feature_aa64_mte_insn_reg(const ARMISARegisters *id)
+{
+    return FIELD_EX64(id->id_aa64pfr1, ID_AA64PFR1, MTE) != 0;
+}
+
+static inline bool isar_feature_aa64_mte(const ARMISARegisters *id)
+{
+    return FIELD_EX64(id->id_aa64pfr1, ID_AA64PFR1, MTE) >= 2;
+}
+
 /*
  * Forward to the above feature tests given an ARMCPU pointer.
  */
diff --git a/target/arm/internals.h b/target/arm/internals.h
index 232d963875..dcc5d6cca3 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -983,6 +983,7 @@ typedef struct ARMVAParameters {
     bool tbid       : 1;
     bool epd        : 1;
     bool hpd        : 1;
+    bool tcma       : 1;
     bool using16k   : 1;
     bool using64k   : 1;
 } ARMVAParameters;
@@ -1007,6 +1008,24 @@ static inline int exception_target_el(CPUARMState *env)
     return target_el;
 }
 
+/* Determine if allocation tags are available.  */
+static inline bool allocation_tag_access_enabled(CPUARMState *env, int el,
+                                                 uint64_t sctlr)
+{
+    if (el < 3
+        && arm_feature(env, ARM_FEATURE_EL3)
+        && !(env->cp15.scr_el3 & SCR_ATA)) {
+        return false;
+    }
+    if (el < 2
+        && arm_feature(env, ARM_FEATURE_EL2)
+        && !(arm_hcr_el2_eff(env) & HCR_ATA)) {
+        return false;
+    }
+    sctlr &= (el == 0 ? SCTLR_ATA0 : SCTLR_ATA);
+    return sctlr != 0;
+}
+
 #ifndef CONFIG_USER_ONLY
 
 /* Security attributes for an address, as returned by v8m_security_lookup. */
diff --git a/target/arm/translate.h b/target/arm/translate.h
index dd24f91f26..9913c35cc2 100644
--- a/target/arm/translate.h
+++ b/target/arm/translate.h
@@ -75,6 +75,8 @@ typedef struct DisasContext {
     bool is_ldex;
     /* True if v8.3-PAuth is active.  */
     bool pauth_active;
+    /* True if v8.5-MTE tag checks affect the PE.  */
+    bool mte_active;
     /* True with v8.5-BTI and SCTLR_ELx.BT* set.  */
     bool bt;
     /*
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 0d9a2d2ab7..b690eda136 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -1904,6 +1904,9 @@ static void scr_write(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t value)
     if (cpu_isar_feature(aa64_pauth, cpu)) {
         valid_mask |= SCR_API | SCR_APK;
     }
+    if (cpu_isar_feature(aa64_mte, cpu)) {
+        valid_mask |= SCR_ATA;
+    }
 
     /* Clear all-context RES0 bits.  */
     value &= valid_mask;
@@ -4158,22 +4161,31 @@ static void sctlr_write(CPUARMState *env, const ARMCPRegInfo *ri,
 {
     ARMCPU *cpu = env_archcpu(env);
 
-    if (raw_read(env, ri) == value) {
-        /* Skip the TLB flush if nothing actually changed; Linux likes
-         * to do a lot of pointless SCTLR writes.
-         */
-        return;
-    }
-
     if (arm_feature(env, ARM_FEATURE_PMSA) && !cpu->has_mpu) {
         /* M bit is RAZ/WI for PMSA with no MPU implemented */
         value &= ~SCTLR_M;
     }
 
-    raw_write(env, ri, value);
+    if (!cpu_isar_feature(aa64_mte, cpu)) {
+        if (ri->opc1 == 6) { /* SCTLR_EL3 */
+            value &= ~(SCTLR_ITFSB | SCTLR_TCF | SCTLR_ATA);
+        } else {
+            value &= ~(SCTLR_ITFSB | SCTLR_TCF0 | SCTLR_TCF |
+                       SCTLR_ATA0 | SCTLR_ATA);
+        }
+    }
+
     /* ??? Lots of these bits are not implemented.  */
-    /* This may enable/disable the MMU, so do a TLB flush.  */
-    tlb_flush(CPU(cpu));
+
+    if (raw_read(env, ri) != value) {
+        /*
+         * This may enable/disable the MMU, so do a TLB flush.
+         * Skip the TLB flush if nothing actually changed;
+         * Linux likes to do a lot of pointless SCTLR writes.
+         */
+        raw_write(env, ri, value);
+        tlb_flush(CPU(cpu));
+    }
 }
 
 static CPAccessResult fpexc32_access(CPUARMState *env, const ARMCPRegInfo *ri,
@@ -4679,6 +4691,9 @@ static void hcr_write(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t value)
     if (cpu_isar_feature(aa64_pauth, cpu)) {
         valid_mask |= HCR_API | HCR_APK;
     }
+    if (cpu_isar_feature(aa64_mte, cpu)) {
+        valid_mask |= HCR_ATA;
+    }
 
     /* Clear RES0 bits.  */
     value &= valid_mask;
@@ -9302,7 +9317,7 @@ ARMVAParameters aa64_va_parameters_both(CPUARMState *env, uint64_t va,
 {
     uint64_t tcr = regime_tcr(env, mmu_idx)->raw_tcr;
     uint32_t el = regime_el(env, mmu_idx);
-    bool tbi, tbid, epd, hpd, using16k, using64k;
+    bool tbi, tbid, epd, hpd, tcma, using16k, using64k;
     int select, tsz;
 
     /*
@@ -9317,11 +9332,12 @@ ARMVAParameters aa64_va_parameters_both(CPUARMState *env, uint64_t va,
         using16k = extract32(tcr, 15, 1);
         if (mmu_idx == ARMMMUIdx_S2NS) {
             /* VTCR_EL2 */
-            tbi = tbid = hpd = false;
+            tbi = tbid = hpd = tcma = false;
         } else {
             tbi = extract32(tcr, 20, 1);
             hpd = extract32(tcr, 24, 1);
             tbid = extract32(tcr, 29, 1);
+            tcma = extract32(tcr, 30, 1);
         }
         epd = false;
     } else if (!select) {
@@ -9332,6 +9348,7 @@ ARMVAParameters aa64_va_parameters_both(CPUARMState *env, uint64_t va,
         tbi = extract64(tcr, 37, 1);
         hpd = extract64(tcr, 41, 1);
         tbid = extract64(tcr, 51, 1);
+        tcma = extract64(tcr, 57, 1);
     } else {
         int tg = extract32(tcr, 30, 2);
         using16k = tg == 1;
@@ -9341,6 +9358,7 @@ ARMVAParameters aa64_va_parameters_both(CPUARMState *env, uint64_t va,
         tbi = extract64(tcr, 38, 1);
         hpd = extract64(tcr, 42, 1);
         tbid = extract64(tcr, 52, 1);
+        tcma = extract64(tcr, 58, 1);
     }
     tsz = MIN(tsz, 39);  /* TODO: ARMv8.4-TTST */
     tsz = MAX(tsz, 16);  /* TODO: ARMv8.2-LVA  */
@@ -9352,6 +9370,7 @@ ARMVAParameters aa64_va_parameters_both(CPUARMState *env, uint64_t va,
         .tbid = tbid,
         .epd = epd,
         .hpd = hpd,
+        .tcma = tcma,
         .using16k = using16k,
         .using64k = using64k,
     };
@@ -11065,6 +11084,7 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc,
     if (is_a64(env)) {
         ARMCPU *cpu = env_archcpu(env);
         uint64_t sctlr;
+        int tbid;
 
         *pc = env->pc;
         flags = FIELD_DP32(flags, TBFLAG_ANY, AARCH64_STATE, 1);
@@ -11073,7 +11093,7 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc,
         {
             ARMMMUIdx stage1 = stage_1_mmu_idx(mmu_idx);
             ARMVAParameters p0 = aa64_va_parameters_both(env, 0, stage1);
-            int tbii, tbid;
+            int tbii;
 
             /* FIXME: ARMv8.1-VHE S2 translation regime.  */
             if (regime_el(env, stage1) < 2) {
@@ -11126,6 +11146,21 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc,
             }
             flags = FIELD_DP32(flags, TBFLAG_A64, BTYPE, env->btype);
         }
+
+        /*
+         * Set MTE_ACTIVE if any access may be Checked, and leave clear
+         * if all accesses must be Unchecked:
+         * 1) If no TBI, then there are no tags in the address to check,
+         * 2) If Tag Check Override, then all accesses are Unchecked,
+         * 3) If Tag Check Fail == 0, then Checked access have no effect,
+         * 4) If no Allocation Tag Access, then all accesses are Unchecked.
+         */
+        if (tbid
+            && !(env->pstate & PSTATE_TCO)
+            && (sctlr & (current_el == 0 ? SCTLR_TCF0 : SCTLR_TCF))
+            && allocation_tag_access_enabled(env, current_el, sctlr)) {
+            flags = FIELD_DP32(flags, TBFLAG_A64, MTE_ACTIVE, 1);
+        }
     } else {
         *pc = env->regs[15];
         flags = FIELD_DP32(flags, TBFLAG_A32, THUMB, env->thumb);
diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 2d6cd09634..51f3af9cd9 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -14161,6 +14161,7 @@ static void aarch64_tr_init_disas_context(DisasContextBase *dcbase,
     dc->pauth_active = FIELD_EX32(tb_flags, TBFLAG_A64, PAUTH_ACTIVE);
     dc->bt = FIELD_EX32(tb_flags, TBFLAG_A64, BT);
     dc->btype = FIELD_EX32(tb_flags, TBFLAG_A64, BTYPE);
+    dc->mte_active = FIELD_EX32(tb_flags, TBFLAG_A64, MTE_ACTIVE);
     dc->vec_len = 0;
     dc->vec_stride = 0;
     dc->cp_regs = arm_cpu->cp_regs;
