[PATCH 16/35] target/arm: Trap registers when HCR_EL2.{NV, NV1} == {1, 1}

[Peter Maydell]

When HCR_EL2.{NV,NV1} is {1,1} we must trap five extra registers to
EL2: VBAR_EL1, ELR_EL1, SPSR_EL1, SCXTNUM_EL1 and TFSR_EL1.
Implement these traps.

This trap does not apply when FEAT_NV2 is implemented and enabled;
include the check that HCR_EL2.NV2 is 0 here, to save us having
to come back and add it later.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
I have mostly implemented FEAT_NV2 after FEAT_NV, but in
this particular case it seemed cleaner to include the NV2
bit check from the start.
---
 target/arm/helper.c | 44 ++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 40 insertions(+), 4 deletions(-)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 220ee64df0d..3270fb11049 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -5339,6 +5339,19 @@ static void mdcr_el2_write(CPUARMState *env, const 
ARMCPRegInfo *ri,
     }
 }
 
+static CPAccessResult access_nv1(CPUARMState *env, const ARMCPRegInfo *ri,
+                                 bool isread)
+{
+    if (arm_current_el(env) == 1) {
+        uint64_t hcr_nv = arm_hcr_el2_eff(env) & (HCR_NV | HCR_NV1 | HCR_NV2);
+
+        if (hcr_nv == (HCR_NV | HCR_NV1)) {
+            return CP_ACCESS_TRAP_EL2;
+        }
+    }
+    return CP_ACCESS_OK;
+}
+
 #ifdef CONFIG_USER_ONLY
 /*
  * `IC IVAU` is handled to improve compatibility with JITs that dual-map their
@@ -5687,12 +5700,12 @@ static const ARMCPRegInfo v8_cp_reginfo[] = {
     { .name = "ELR_EL1", .state = ARM_CP_STATE_AA64,
       .type = ARM_CP_ALIAS,
       .opc0 = 3, .opc1 = 0, .crn = 4, .crm = 0, .opc2 = 1,
-      .access = PL1_RW,
+      .access = PL1_RW, .accessfn = access_nv1,
       .fieldoffset = offsetof(CPUARMState, elr_el[1]) },
     { .name = "SPSR_EL1", .state = ARM_CP_STATE_AA64,
       .type = ARM_CP_ALIAS,
       .opc0 = 3, .opc1 = 0, .crn = 4, .crm = 0, .opc2 = 0,
-      .access = PL1_RW,
+      .access = PL1_RW, .accessfn = access_nv1,
       .fieldoffset = offsetof(CPUARMState, banked_spsr[BANK_SVC]) },
     /*
      * We rely on the access checks not allowing the guest to write to the
@@ -7807,6 +7820,16 @@ static CPAccessResult access_mte(CPUARMState *env, const 
ARMCPRegInfo *ri,
     }
     return CP_ACCESS_OK;
 }
+static CPAccessResult access_tfsr_el1(CPUARMState *env, const ARMCPRegInfo *ri,
+                                      bool isread)
+{
+    CPAccessResult nv1 = access_nv1(env, ri, isread);
+
+    if (nv1 != CP_ACCESS_OK) {
+        return nv1;
+    }
+    return access_mte(env, ri, isread);
+}
 
 static CPAccessResult access_tfsr_el2(CPUARMState *env, const ARMCPRegInfo *ri,
                                       bool isread)
@@ -7852,7 +7875,7 @@ static const ARMCPRegInfo mte_reginfo[] = {
       .fieldoffset = offsetof(CPUARMState, cp15.tfsr_el[0]) },
     { .name = "TFSR_EL1", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 0, .crn = 5, .crm = 6, .opc2 = 0,
-      .access = PL1_RW, .accessfn = access_mte,
+      .access = PL1_RW, .accessfn = access_tfsr_el1,
       .fieldoffset = offsetof(CPUARMState, cp15.tfsr_el[1]) },
     { .name = "TFSR_EL2", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 4, .crn = 5, .crm = 6, .opc2 = 0,
@@ -8004,6 +8027,18 @@ static CPAccessResult access_scxtnum(CPUARMState *env, 
const ARMCPRegInfo *ri,
     return CP_ACCESS_OK;
 }
 
+static CPAccessResult access_scxtnum_el1(CPUARMState *env,
+                                         const ARMCPRegInfo *ri,
+                                         bool isread)
+{
+    CPAccessResult nv1 = access_nv1(env, ri, isread);
+
+    if (nv1 != CP_ACCESS_OK) {
+        return nv1;
+    }
+    return access_scxtnum(env, ri, isread);
+}
+
 static const ARMCPRegInfo scxtnum_reginfo[] = {
     { .name = "SCXTNUM_EL0", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 3, .crn = 13, .crm = 0, .opc2 = 7,
@@ -8012,7 +8047,7 @@ static const ARMCPRegInfo scxtnum_reginfo[] = {
       .fieldoffset = offsetof(CPUARMState, scxtnum_el[0]) },
     { .name = "SCXTNUM_EL1", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 0, .crn = 13, .crm = 0, .opc2 = 7,
-      .access = PL1_RW, .accessfn = access_scxtnum,
+      .access = PL1_RW, .accessfn = access_scxtnum_el1,
       .fgt = FGT_SCXTNUM_EL1,
       .fieldoffset = offsetof(CPUARMState, scxtnum_el[1]) },
     { .name = "SCXTNUM_EL2", .state = ARM_CP_STATE_AA64,
@@ -9394,6 +9429,7 @@ void register_cp_regs_for_features(ARMCPU *cpu)
             { .name = "VBAR", .state = ARM_CP_STATE_BOTH,
               .opc0 = 3, .crn = 12, .crm = 0, .opc1 = 0, .opc2 = 0,
               .access = PL1_RW, .writefn = vbar_write,
+              .accessfn = access_nv1,
               .fgt = FGT_VBAR_EL1,
               .bank_fieldoffsets = { offsetof(CPUARMState, cp15.vbar_s),
                                      offsetof(CPUARMState, cp15.vbar_ns) },
-- 
2.34.1