[PATCH v4 23/24] target/arm: Implement FEAT_HAFDBS, dirty bit portion

[Richard Henderson]

Perform the atomic update for hardware management of the dirty bit.

Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
 target/arm/cpu64.c |  2 +-
 target/arm/ptw.c   | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index fe1369fe96..0732796559 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -1165,7 +1165,7 @@ static void aarch64_max_initfn(Object *obj)
     cpu->isar.id_aa64mmfr0 = t;
 
     t = cpu->isar.id_aa64mmfr1;
-    t = FIELD_DP64(t, ID_AA64MMFR1, HAFDBS, 1);   /* FEAT_HAFDBS, AF only */
+    t = FIELD_DP64(t, ID_AA64MMFR1, HAFDBS, 2);   /* FEAT_HAFDBS */
     t = FIELD_DP64(t, ID_AA64MMFR1, VMIDBITS, 2); /* FEAT_VMID16 */
     t = FIELD_DP64(t, ID_AA64MMFR1, VH, 1);       /* FEAT_VHE */
     t = FIELD_DP64(t, ID_AA64MMFR1, HPDS, 1);     /* FEAT_HPDS */
diff --git a/target/arm/ptw.c b/target/arm/ptw.c
index 82b6ab029e..0dbbb7d4d4 100644
--- a/target/arm/ptw.c
+++ b/target/arm/ptw.c
@@ -1484,10 +1484,30 @@ static bool get_phys_addr_lpae(CPUARMState *env, 
S1Translate *ptw,
     ap = extract32(attrs, 6, 2);
 
     if (mmu_idx == ARMMMUIdx_Stage2 || mmu_idx == ARMMMUIdx_Stage2_S) {
+        if (param.hd
+            && extract64(attrs, 51, 1)  /* DBM */
+            && access_type == MMU_DATA_STORE) {
+            /*
+             * Pre-emptively set S2AP[1], so that we compute EXEC properly.
+             * C.f. AArch64.S2ApplyOutputPerms, which does the same thing.
+             */
+            ap |= 2;
+            new_descriptor |= 1ull << 7;
+        }
         ns = mmu_idx == ARMMMUIdx_Stage2;
         xn = extract64(attrs, 54, 2);
         result->f.prot = get_S2prot(env, ap, xn, s1_is_el0);
     } else {
+        if (param.hd
+            && extract64(attrs, 51, 1)  /* DBM */
+            && access_type == MMU_DATA_STORE) {
+            /*
+             * Pre-emptively clear AP[2], so that we compute EXEC properly.
+             * C.f. AArch64.S1ApplyOutputPerms, which does the same thing.
+             */
+            ap &= ~2;
+            new_descriptor &= ~(1ull << 7);
+        }
         ns = extract32(attrs, 5, 1);
         xn = extract64(attrs, 54, 1);
         pxn = extract64(attrs, 53, 1);
-- 
2.34.1