target/arm: Enable FEAT_CSV3 for -cpu max

This extension concerns cache speculation, which TCG does
not implement.  Thus we can trivially enable this feature.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220506180242.216785-22-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

docs/system/arm/emulation.rst

@@ -16,6 +16,7 @@ the following architecture extensions:
 - FEAT_CSV2_1p1 (Cache speculation variant 2, version 1.1)
 - FEAT_CSV2_1p2 (Cache speculation variant 2, version 1.2)
 - FEAT_CSV2_2 (Cache speculation variant 2, version 2)
+- FEAT_CSV3 (Cache speculation variant 3)
 - FEAT_DIT (Data Independent Timing instructions)
 - FEAT_DPB (DC CVAP instruction)
 - FEAT_Debugv8p2 (Debug changes for v8.2)

target/arm/cpu64.c

@@ -749,6 +749,7 @@ static void aarch64_max_initfn(Object *obj)
     t = FIELD_DP64(t, ID_AA64PFR0, SEL2, 1);      /* FEAT_SEL2 */
     t = FIELD_DP64(t, ID_AA64PFR0, DIT, 1);       /* FEAT_DIT */
     t = FIELD_DP64(t, ID_AA64PFR0, CSV2, 2);      /* FEAT_CSV2_2 */
+    t = FIELD_DP64(t, ID_AA64PFR0, CSV3, 1);      /* FEAT_CSV3 */
     cpu->isar.id_aa64pfr0 = t;
 
     t = cpu->isar.id_aa64pfr1;

target/arm/cpu_tcg.c

@@ -74,6 +74,7 @@ void aa32_max_features(ARMCPU *cpu)
     cpu->isar.id_pfr0 = t;
 
     t = cpu->isar.id_pfr2;
+    t = FIELD_DP32(t, ID_PFR2, CSV3, 1);          /* FEAT_CSV3 */
     t = FIELD_DP32(t, ID_PFR2, SSBS, 1);          /* FEAT_SSBS */
     cpu->isar.id_pfr2 = t;