[RFC PATCH v9 05/23] target/arm: Support MSR access to ALLINT

[Jinjie Ruan]

Support ALLINT msr access as follow:
        mrs <xt>, ALLINT        // read allint
        msr ALLINT, <xt>        // write allint with imm

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
v9:
- Move nmi_reginfo and related functions inside an existing ifdef
  TARGET_AARCH64 to solve the --target-list=aarch64-softmmu,arm-softmmu
  compilation problem.
- Check 'isread' when writing to ALLINT.
v5:
- Add Reviewed-by.
v4:
- Remove arm_is_el2_enabled() check in allint_check().
- Change to env->pstate instead of env->allint.
v3:
- Remove EL0 check in aa64_allint_access() which alreay checks in .access
  PL1_RW.
- Use arm_hcrx_el2_eff() in aa64_allint_access() instead of env->cp15.hcrx_el2.
- Make ALLINT msr access function controlled by aa64_nmi.
---
 target/arm/helper.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 7d6c6e9878..a65729af66 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -7497,6 +7497,37 @@ static const ARMCPRegInfo rme_mte_reginfo[] = {
       .opc0 = 1, .opc1 = 6, .crn = 7, .crm = 14, .opc2 = 5,
       .access = PL3_W, .type = ARM_CP_NOP },
 };
+
+static void aa64_allint_write(CPUARMState *env, const ARMCPRegInfo *ri,
+                              uint64_t value)
+{
+    env->pstate = (env->pstate & ~PSTATE_ALLINT) | (value & PSTATE_ALLINT);
+}
+
+static uint64_t aa64_allint_read(CPUARMState *env, const ARMCPRegInfo *ri)
+{
+    return env->pstate & PSTATE_ALLINT;
+}
+
+static CPAccessResult aa64_allint_access(CPUARMState *env,
+                                         const ARMCPRegInfo *ri, bool isread)
+{
+    if (!isread && arm_current_el(env) == 1 &&
+        (arm_hcrx_el2_eff(env) & HCRX_TALLINT)) {
+        return CP_ACCESS_TRAP_EL2;
+    }
+    return CP_ACCESS_OK;
+}
+
+static const ARMCPRegInfo nmi_reginfo[] = {
+    { .name = "ALLINT", .state = ARM_CP_STATE_AA64,
+      .opc0 = 3, .opc1 = 0, .opc2 = 0, .crn = 4, .crm = 3,
+      .type = ARM_CP_NO_RAW,
+      .access = PL1_RW, .accessfn = aa64_allint_access,
+      .fieldoffset = offsetof(CPUARMState, pstate),
+      .writefn = aa64_allint_write, .readfn = aa64_allint_read,
+      .resetfn = arm_cp_reset_ignore },
+};
 #endif /* TARGET_AARCH64 */
 
 static void define_pmu_regs(ARMCPU *cpu)
@@ -9891,6 +9922,10 @@ void register_cp_regs_for_features(ARMCPU *cpu)
     if (cpu_isar_feature(aa64_nv2, cpu)) {
         define_arm_cp_regs(cpu, nv2_reginfo);
     }
+
+    if (cpu_isar_feature(aa64_nmi, cpu)) {
+        define_arm_cp_regs(cpu, nmi_reginfo);
+    }
 #endif
 
     if (cpu_isar_feature(any_predinv, cpu)) {
-- 
2.34.1