target/arm: Add support for FEAT_DIT, Data Independent Timing

Add support for FEAT_DIT. DIT (Data Independent Timing) is a required
feature for ARMv8.4. Since virtual machine execution is largely
nondeterministic and TCG is outside of the security domain, it's
implemented as a NOP.

Signed-off-by: Rebecca Cran <rebecca@nuviainc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210208065700.19454-2-rebecca@nuviainc.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/target/arm/internals.h b/target/arm/internals.h
index 448982dd2f..b251fe4450 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -1228,6 +1228,9 @@ static inline uint32_t aarch32_cpsr_valid_mask(uint64_t features,
     if (isar_feature_aa32_pan(id)) {
         valid |= CPSR_PAN;
     }
+    if (isar_feature_aa32_dit(id)) {
+        valid |= CPSR_DIT;
+    }
 
     return valid;
 }
@@ -1246,6 +1249,9 @@ static inline uint32_t aarch64_pstate_valid_mask(const ARMISARegisters *id)
     if (isar_feature_aa64_uao(id)) {
         valid |= PSTATE_UAO;
     }
+    if (isar_feature_aa64_dit(id)) {
+        valid |= PSTATE_DIT;
+    }
     if (isar_feature_aa64_mte(id)) {
         valid |= PSTATE_TCO;
     }