Accurately injecting an ARM Processor error ACPI/APEI GHES
error record requires the value of the ARM Multiprocessor
Affinity Register (mpidr).

While ARM implements it, this is currently not visible.

Add a field at CPU storing it, and place it at arm_cpu_properties
as experimental, thus allowing it to be queried via QMP using
qom-get function.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 target/arm/cpu.c    |  1 +
 target/arm/cpu.h    |  1 +
 target/arm/helper.c | 10 ++++++++--
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 19191c239181..30fcf0a10f46 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -2619,6 +2619,7 @@ static ObjectClass *arm_cpu_class_by_name(const char *cpu_model)
 
 static Property arm_cpu_properties[] = {
     DEFINE_PROP_UINT64("midr", ARMCPU, midr, 0),
+    DEFINE_PROP_UINT64("x-mpidr", ARMCPU, mpidr, 0),
     DEFINE_PROP_UINT64("mp-affinity", ARMCPU,
                         mp_affinity, ARM64_AFFINITY_INVALID),
     DEFINE_PROP_INT32("node-id", ARMCPU, node_id, CPU_UNSET_NUMA_NODE_ID),
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index f065756c5c7d..bf8e5943af4f 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -1033,6 +1033,7 @@ struct ArchCPU {
         uint64_t reset_pmcr_el0;
     } isar;
     uint64_t midr;
+    uint64_t mpidr;
     uint32_t revidr;
     uint32_t reset_fpsid;
     uint64_t ctr;
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 0a582c1cd3b3..d6e7aa069489 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -4690,7 +4690,7 @@ static uint64_t mpidr_read_val(CPUARMState *env)
     return mpidr;
 }
 
-static uint64_t mpidr_read(CPUARMState *env, const ARMCPRegInfo *ri)
+static uint64_t mpidr_read(CPUARMState *env)
 {
     unsigned int cur_el = arm_current_el(env);
 
@@ -4700,6 +4700,11 @@ static uint64_t mpidr_read(CPUARMState *env, const ARMCPRegInfo *ri)
     return mpidr_read_val(env);
 }
 
+static uint64_t mpidr_read_ri(CPUARMState *env, const ARMCPRegInfo *ri)
+{
+    return mpidr_read(env);
+}
+
 static const ARMCPRegInfo lpae_cp_reginfo[] = {
     /* NOP AMAIR0/1 */
     { .name = "AMAIR0", .state = ARM_CP_STATE_BOTH,
@@ -9721,7 +9726,7 @@ void register_cp_regs_for_features(ARMCPU *cpu)
             { .name = "MPIDR_EL1", .state = ARM_CP_STATE_BOTH,
               .opc0 = 3, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 5,
               .fgt = FGT_MPIDR_EL1,
-              .access = PL1_R, .readfn = mpidr_read, .type = ARM_CP_NO_RAW },
+              .access = PL1_R, .readfn = mpidr_read_ri, .type = ARM_CP_NO_RAW },
         };
 #ifdef CONFIG_USER_ONLY
         static const ARMCPRegUserSpaceInfo mpidr_user_cp_reginfo[] = {
@@ -9731,6 +9736,7 @@ void register_cp_regs_for_features(ARMCPU *cpu)
         modify_arm_cp_regs(mpidr_cp_reginfo, mpidr_user_cp_reginfo);
 #endif
         define_arm_cp_regs(cpu, mpidr_cp_reginfo);
+        cpu->mpidr = mpidr_read(env);
     }
 
     if (arm_feature(env, ARM_FEATURE_AUXCR)) {
-- 
2.46.0