target-arm: Use the kernel's idea of MPIDR if we're using KVM

When we're using KVM, the kernel's internal idea of the MPIDR
affinity fields must match the values we tell it for the guest
vcpu cluster configuration in the device tree. Since at the moment
the kernel doesn't support letting userspace tell it the correct
affinity fields to use, we must read the kernel's view and
reflect that back in the device tree.

Signed-off-by: Shlomo Pongratz <shlomo.pongratz@huawei.com>
Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
Message-id: 02f601d0a1e6$90c7d630$b2578290$@samsung.com
[PMM: Use a local #define rather than a global variable for
 the TCG ARM_CPUS_PER_CLUSTER setting. Tweak a comment. Update the
 commit message.]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/target-arm/cpu.c b/target-arm/cpu.c
index 4a888ab..34990ac 100644
--- a/target-arm/cpu.c
+++ b/target-arm/cpu.c
@@ -383,17 +383,29 @@ static inline void unset_feature(CPUARMState *env, int feature)
     env->features &= ~(1ULL << feature);
 }
 
+#define ARM_CPUS_PER_CLUSTER 8
+
 static void arm_cpu_initfn(Object *obj)
 {
     CPUState *cs = CPU(obj);
     ARMCPU *cpu = ARM_CPU(obj);
     static bool inited;
+    uint32_t Aff1, Aff0;
 
     cs->env_ptr = &cpu->env;
     cpu_exec_init(&cpu->env);
     cpu->cp_regs = g_hash_table_new_full(g_int_hash, g_int_equal,
                                          g_free, g_free);
 
+    /* This cpu-id-to-MPIDR affinity is used only for TCG; KVM will override it.
+     * We don't support setting cluster ID ([16..23]) (known as Aff2
+     * in later ARM ARM versions), or any of the higher affinity level fields,
+     * so these bits always RAZ.
+     */
+    Aff1 = cs->cpu_index / ARM_CPUS_PER_CLUSTER;
+    Aff0 = cs->cpu_index % ARM_CPUS_PER_CLUSTER;
+    cpu->mp_affinity = (Aff1 << 8) | Aff0;
+
 #ifndef CONFIG_USER_ONLY
     /* Our inbound IRQ and FIQ lines */
     if (kvm_enabled()) {