[RFC PATCH v8 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>
---
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 | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index b19a0178ce..aa0151c775 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -4752,6 +4752,36 @@ static void aa64_daif_write(CPUARMState *env, const 
ARMCPRegInfo *ri,
     env->daif = value & PSTATE_DAIF;
 }
 
+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 (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 },
+};
+
 static uint64_t aa64_pan_read(CPUARMState *env, const ARMCPRegInfo *ri)
 {
     return env->pstate & PSTATE_PAN;
@@ -9889,6 +9919,10 @@ 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