[PATCH v4 09/13] target/arm: with MTX, no tag bit bounds check

[Gabriel Brookman <brookmangabriel@gmail.com>]

Virtual address canonicity checks should ignore mismatch in tag bits
during translation step if MTX is set.

Signed-off-by: Gabriel Brookman <brookmangabriel@gmail.com>
---
 target/arm/helper.c    |  6 +++++-
 target/arm/internals.h |  1 +
 target/arm/ptw.c       | 28 +++++++++++++++++++++++++---
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 56858367fd..a61944dedd 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -9747,7 +9747,7 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env, uint64_t va,
 {
     uint64_t tcr = regime_tcr(env, mmu_idx);
     bool epd, hpd, tsz_oob, ds, ha, hd, pie = false;
-    bool aie = false;
+    bool aie, mtx = false;
     int select, tsz, tbi, max_tsz, min_tsz, ps, sh;
     ARMGranuleSize gran;
     ARMCPU *cpu = env_archcpu(env);
@@ -9784,6 +9784,7 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env, uint64_t va,
         ha = extract32(tcr, 21, 1) && cpu_isar_feature(aa64_hafs, cpu);
         hd = extract32(tcr, 22, 1) && cpu_isar_feature(aa64_hdbs, cpu);
         ds = extract64(tcr, 32, 1);
+        mtx = extract64(tcr, 33, 1) && cpu_isar_feature(aa64_mte_mtx, cpu);
     } else {
         bool e0pd;
 
@@ -9799,6 +9800,7 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env, uint64_t va,
             sh = extract32(tcr, 12, 2);
             hpd = extract64(tcr, 41, 1);
             e0pd = extract64(tcr, 55, 1);
+            mtx = extract64(tcr, 60, 1) && cpu_isar_feature(aa64_mte_mtx, cpu);
         } else {
             tsz = extract32(tcr, 16, 6);
             gran = tg1_to_gran_size(extract32(tcr, 30, 2));
@@ -9806,6 +9808,7 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env, uint64_t va,
             sh = extract32(tcr, 28, 2);
             hpd = extract64(tcr, 42, 1);
             e0pd = extract64(tcr, 56, 1);
+            mtx = extract64(tcr, 61, 1) && cpu_isar_feature(aa64_mte_mtx, cpu);
         }
         ps = extract64(tcr, 32, 3);
         ha = extract64(tcr, 39, 1) && cpu_isar_feature(aa64_hafs, cpu);
@@ -9905,6 +9908,7 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env, uint64_t va,
         .gran = gran,
         .pie = pie,
         .aie = aie,
+        .mtx = mtx,
     };
 }
 
diff --git a/target/arm/internals.h b/target/arm/internals.h
index 52597a351c..2c4369cc16 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -1396,6 +1396,7 @@ typedef struct ARMVAParameters {
     ARMGranuleSize gran : 2;
     bool pie        : 1;
     bool aie        : 1;
+    bool mtx        : 1;
 } ARMVAParameters;
 
 /**
diff --git a/target/arm/ptw.c b/target/arm/ptw.c
index d381413ef7..e31b3085f8 100644
--- a/target/arm/ptw.c
+++ b/target/arm/ptw.c
@@ -1929,7 +1929,16 @@ static bool get_phys_addr_lpae(CPUARMState *env, S1Translate *ptw,
      * validation to do here.
      */
     if (inputsize < addrsize) {
-        uint64_t top_bits = sextract64(address, inputsize,
+        /*
+         * If MTX is enabled, bits 56-59 aren't checked for canonicity
+         * during translation, since they will later be checked during
+         * the tag check step.
+         */
+        uint64_t masked_address = address;
+        if (param.mtx) {
+            masked_address = deposit64(address, 56, 4, param.select * 0xf);
+        }
+        uint64_t top_bits = sextract64(masked_address, inputsize,
                                            addrsize - inputsize);
         if (-top_bits != param.select) {
             /* The gap between the two regions is a Translation fault */
@@ -3481,15 +3490,28 @@ static bool get_phys_addr_disabled(CPUARMState *env,
         if (arm_el_is_aa64(env, r_el)) {
             int pamax = arm_pamax(env_archcpu(env));
             uint64_t tcr = env->cp15.tcr_el[r_el];
-            int addrtop, tbi;
+            int addrtop, tbi, mtx;
+            bool bit55;
 
             tbi = aa64_va_parameter_tbi(tcr, mmu_idx);
+            mtx = aa64_va_parameter_mtx(tcr, mmu_idx);
             if (access_type == MMU_INST_FETCH) {
                 tbi &= ~aa64_va_parameter_tbid(tcr, mmu_idx);
             }
-            tbi = (tbi >> extract64(address, 55, 1)) & 1;
+            bit55 = extract64(address, 55, 1);
+            tbi = (tbi >> bit55) & 1;
+            mtx = (mtx >> bit55) & 1;
             addrtop = (tbi ? 55 : 63);
 
+            /*
+             * With MTX enabled, bits 56-59 are not checked according to
+             * AArch64.S1DisabledOutput.
+             */
+            if (cpu_isar_feature(aa64_mte_mtx, env_archcpu(env)) && mtx &&
+                access_type != MMU_INST_FETCH) {
+                address = deposit64(address, 56, 4, ((mmu_idx) && bit55) * 0xF);
+            }
+
             if (extract64(address, pamax, addrtop - pamax + 1) != 0) {
                 fi->type = ARMFault_AddressSize;
                 fi->level = 0;

-- 
2.52.0