target/arm: Update get_a64_user_mem_index for VHE

The EL2&0 translation regime is affected by Load Register (unpriv).

The code structure used here will facilitate later changes in this
area for implementing UAO and NV.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200206105448.4726-36-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

4 files changed, 57 insertions, 20 deletions

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index d091a7e..2ed2667 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -3214,10 +3214,10 @@ typedef ARMCPU ArchCPU;
  * |              |     |   TBFLAG_A32   |              |
  * |              |     +-----+----------+  TBFLAG_AM32 |
  * |  TBFLAG_ANY  |           |TBFLAG_M32|              |
- * |              |           +-------------------------|
- * |              |           |       TBFLAG_A64        |
- * +--------------+-----------+-------------------------+
- *  31          20          14                         0
+ * |              |         +-+----------+--------------|
+ * |              |         |         TBFLAG_A64        |
+ * +--------------+---------+---------------------------+
+ *  31          20        15                           0
  *
  * Unless otherwise noted, these bits are cached in env->hflags.
  */
@@ -3283,6 +3283,7 @@ FIELD(TBFLAG_A64, PAUTH_ACTIVE, 8, 1)
 FIELD(TBFLAG_A64, BT, 9, 1)
 FIELD(TBFLAG_A64, BTYPE, 10, 2)         /* Not cached. */
 FIELD(TBFLAG_A64, TBID, 12, 2)
+FIELD(TBFLAG_A64, UNPRIV, 14, 1)
 
 static inline bool bswap_code(bool sctlr_b)
 {
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 9627b4a..ff2d957 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -12011,6 +12011,28 @@ static uint32_t rebuild_hflags_a64(CPUARMState *env, int el, int fp_el,
         }
     }
 
+    /* Compute the condition for using AccType_UNPRIV for LDTR et al. */
+    /* TODO: ARMv8.2-UAO */
+    switch (mmu_idx) {
+    case ARMMMUIdx_E10_1:
+    case ARMMMUIdx_SE10_1:
+        /* TODO: ARMv8.3-NV */
+        flags = FIELD_DP32(flags, TBFLAG_A64, UNPRIV, 1);
+        break;
+    case ARMMMUIdx_E20_2:
+        /* TODO: ARMv8.4-SecEL2 */
+        /*
+         * Note that E20_2 is gated by HCR_EL2.E2H == 1, but E20_0 is
+         * gated by HCR_EL2.<E2H,TGE> == '11', and so is LDTR.
+         */
+        if (env->cp15.hcr_el2 & HCR_TGE) {
+            flags = FIELD_DP32(flags, TBFLAG_A64, UNPRIV, 1);
+        }
+        break;
+    default:
+        break;
+    }
+
     return rebuild_hflags_common(env, fp_el, mmu_idx, flags);
 }
 
diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 3982e19..6e82486 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -105,25 +105,36 @@ void a64_translate_init(void)
         offsetof(CPUARMState, exclusive_high), "exclusive_high");
 }
 
-static inline int get_a64_user_mem_index(DisasContext *s)
+/*
+ * Return the core mmu_idx to use for A64 "unprivileged load/store" insns
+ */
+static int get_a64_user_mem_index(DisasContext *s)
 {
-    /* Return the core mmu_idx to use for A64 "unprivileged load/store" insns:
-     *  if EL1, access as if EL0; otherwise access at current EL
+    /*
+     * If AccType_UNPRIV is not used, the insn uses AccType_NORMAL,
+     * which is the usual mmu_idx for this cpu state.
      */
-    ARMMMUIdx useridx;
+    ARMMMUIdx useridx = s->mmu_idx;
 
-    switch (s->mmu_idx) {
-    case ARMMMUIdx_E10_1:
-        useridx = ARMMMUIdx_E10_0;
-        break;
-    case ARMMMUIdx_SE10_1:
-        useridx = ARMMMUIdx_SE10_0;
-        break;
-    case ARMMMUIdx_Stage2:
-        g_assert_not_reached();
-    default:
-        useridx = s->mmu_idx;
-        break;
+    if (s->unpriv) {
+        /*
+         * We have pre-computed the condition for AccType_UNPRIV.
+         * Therefore we should never get here with a mmu_idx for
+         * which we do not know the corresponding user mmu_idx.
+         */
+        switch (useridx) {
+        case ARMMMUIdx_E10_1:
+            useridx = ARMMMUIdx_E10_0;
+            break;
+        case ARMMMUIdx_E20_2:
+            useridx = ARMMMUIdx_E20_0;
+            break;
+        case ARMMMUIdx_SE10_1:
+            useridx = ARMMMUIdx_SE10_0;
+            break;
+        default:
+            g_assert_not_reached();
+        }
     }
     return arm_to_core_mmu_idx(useridx);
 }
@@ -14171,6 +14182,7 @@ static void aarch64_tr_init_disas_context(DisasContextBase *dcbase,
     dc->pauth_active = FIELD_EX32(tb_flags, TBFLAG_A64, PAUTH_ACTIVE);
     dc->bt = FIELD_EX32(tb_flags, TBFLAG_A64, BT);
     dc->btype = FIELD_EX32(tb_flags, TBFLAG_A64, BTYPE);
+    dc->unpriv = FIELD_EX32(tb_flags, TBFLAG_A64, UNPRIV);
     dc->vec_len = 0;
     dc->vec_stride = 0;
     dc->cp_regs = arm_cpu->cp_regs;
diff --git a/target/arm/translate.h b/target/arm/translate.h
index a32b6b1..5b167c4 100644
--- a/target/arm/translate.h
+++ b/target/arm/translate.h
@@ -73,6 +73,8 @@ typedef struct DisasContext {
      * ie A64 LDX*, LDAX*, A32/T32 LDREX*, LDAEX*.
      */
     bool is_ldex;
+    /* True if AccType_UNPRIV should be used for LDTR et al */
+    bool unpriv;
     /* True if v8.3-PAuth is active.  */
     bool pauth_active;
     /* True with v8.5-BTI and SCTLR_ELx.BT* set.  */