[PATCH v4 03/18] target/arm: Fault on invalid TCR_ELx.TxSZ

[Richard Henderson <richard.henderson@linaro.org>]

Without FEAT_LVA, the behaviour of programming an invalid value
is IMPLEMENTATION DEFINED.  With FEAT_LVA, programming an invalid
minimum value requires a Translation fault.

It is most self-consistent to choose to generate the fault always.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
v2: Continue to bound in aa64_va_parameters, so that PAuth gets
    something it can use, but provide a flag for get_phys_addr_lpae
    to raise a fault.
---
 target/arm/internals.h |  1 +
 target/arm/helper.c    | 32 ++++++++++++++++++++++++++++----
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/target/arm/internals.h b/target/arm/internals.h
index 3f05748ea4..ef6c25d8cb 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -1055,6 +1055,7 @@ typedef struct ARMVAParameters {
     bool hpd        : 1;
     bool using16k   : 1;
     bool using64k   : 1;
+    bool tsz_oob    : 1;  /* tsz has been clamped to legal range */
 } ARMVAParameters;
 
 ARMVAParameters aa64_va_parameters(CPUARMState *env, uint64_t va,
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 7bf50fdd76..dd4d95bda2 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -11190,8 +11190,8 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env, uint64_t va,
                                    ARMMMUIdx mmu_idx, bool data)
 {
     uint64_t tcr = regime_tcr(env, mmu_idx)->raw_tcr;
-    bool epd, hpd, using16k, using64k;
-    int select, tsz, tbi, max_tsz;
+    bool epd, hpd, using16k, using64k, tsz_oob;
+    int select, tsz, tbi, max_tsz, min_tsz;
 
     if (!regime_has_2_ranges(mmu_idx)) {
         select = 0;
@@ -11232,9 +11232,17 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env, uint64_t va,
     } else {
         max_tsz = 39;
     }
+    min_tsz = 16;  /* TODO: ARMv8.2-LVA  */
 
-    tsz = MIN(tsz, max_tsz);
-    tsz = MAX(tsz, 16);  /* TODO: ARMv8.2-LVA  */
+    if (tsz > max_tsz) {
+        tsz = max_tsz;
+        tsz_oob = true;
+    } else if (tsz < min_tsz) {
+        tsz = min_tsz;
+        tsz_oob = true;
+    } else {
+        tsz_oob = false;
+    }
 
     /* Present TBI as a composite with TBID.  */
     tbi = aa64_va_parameter_tbi(tcr, mmu_idx);
@@ -11251,6 +11259,7 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env, uint64_t va,
         .hpd = hpd,
         .using16k = using16k,
         .using64k = using64k,
+        .tsz_oob = tsz_oob,
     };
 }
 
@@ -11374,6 +11383,21 @@ static bool get_phys_addr_lpae(CPUARMState *env, uint64_t address,
         param = aa64_va_parameters(env, address, mmu_idx,
                                    access_type != MMU_INST_FETCH);
         level = 0;
+
+        /*
+         * If TxSZ is programmed to a value larger than the maximum,
+         * or smaller than the effective minimum, it is IMPLEMENTATION
+         * DEFINED whether we behave as if the field were programmed
+         * within bounds, or if a level 0 Translation fault is generated.
+         *
+         * With FEAT_LVA, fault on less than minimum becomes required,
+         * so our choice is to always raise the fault.
+         */
+        if (param.tsz_oob) {
+            fault_type = ARMFault_Translation;
+            goto do_fault;
+        }
+
         addrsize = 64 - 8 * param.tbi;
         inputsize = 64 - param.tsz;
     } else {
-- 
2.25.1