[PATCH 1/6] target/arm: Fault on invalid TCR_ELx.TxSZ

[Richard Henderson]

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.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/helper.c | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 9b317899a6..575723d62c 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -11129,7 +11129,7 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env, 
uint64_t va,
 {
     uint64_t tcr = regime_tcr(env, mmu_idx)->raw_tcr;
     bool epd, hpd, using16k, using64k;
-    int select, tsz, tbi, max_tsz;
+    int select, tsz, tbi;
 
     if (!regime_has_2_ranges(mmu_idx)) {
         select = 0;
@@ -11165,15 +11165,6 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env, 
uint64_t va,
         }
     }
 
-    if (cpu_isar_feature(aa64_st, env_archcpu(env))) {
-        max_tsz = 48 - using64k;
-    } else {
-        max_tsz = 39;
-    }
-
-    tsz = MIN(tsz, max_tsz);
-    tsz = MAX(tsz, 16);  /* TODO: ARMv8.2-LVA  */
-
     /* Present TBI as a composite with TBID.  */
     tbi = aa64_va_parameter_tbi(tcr, mmu_idx);
     if (!data) {
@@ -11309,9 +11300,30 @@ static bool get_phys_addr_lpae(CPUARMState *env, 
uint64_t address,
 
     /* TODO: This code does not support shareability levels. */
     if (aarch64) {
+        int min_tsz = 16, max_tsz = 39;  /* TODO: ARMv8.2-LVA  */
+
         param = aa64_va_parameters(env, address, mmu_idx,
                                    access_type != MMU_INST_FETCH);
         level = 0;
+
+        if (cpu_isar_feature(aa64_st, env_archcpu(env))) {
+            max_tsz = 48 - param.using64k;
+        }
+
+        /*
+         * 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 < min_tsz || param.tsz > max_tsz) {
+            fault_type = ARMFault_Translation;
+            goto do_fault;
+        }
+
         addrsize = 64 - 8 * param.tbi;
         inputsize = 64 - param.tsz;
     } else {
-- 
2.25.1