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, 15 insertions, 0 deletions

diff --git a/target-arm/kvm64.c b/target-arm/kvm64.c
index 93c1ca8b21..ac34f51498 100644
--- a/target-arm/kvm64.c
+++ b/target-arm/kvm64.c
@@ -77,9 +77,13 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUClass *ahcc)
     return true;
 }
 
+#define ARM_MPIDR_HWID_BITMASK 0xFF00FFFFFFULL
+#define ARM_CPU_ID_MPIDR       3, 0, 0, 0, 5
+
 int kvm_arch_init_vcpu(CPUState *cs)
 {
     int ret;
+    uint64_t mpidr;
     ARMCPU *cpu = ARM_CPU(cs);
 
     if (cpu->kvm_target == QEMU_KVM_ARM_TARGET_NONE ||
@@ -107,6 +111,17 @@ int kvm_arch_init_vcpu(CPUState *cs)
         return ret;
     }
 
+    /*
+     * When KVM is in use, PSCI is emulated in-kernel and not by qemu.
+     * Currently KVM has its own idea about MPIDR assignment, so we
+     * override our defaults with what we get from KVM.
+     */
+    ret = kvm_get_one_reg(cs, ARM64_SYS_REG(ARM_CPU_ID_MPIDR), &mpidr);
+    if (ret) {
+        return ret;
+    }
+    cpu->mp_affinity = mpidr & ARM_MPIDR_HWID_BITMASK;
+
     return kvm_arm_init_cpreg_list(cpu);
 }