ARM/ARM64: KVM: Emulate PSCI v0.2 AFFINITY_INFO

This patch adds emulation of PSCI v0.2 AFFINITY_INFO function call
for KVM ARM/ARM64. This is a VCPU-level function call which will be
used to determine current state of given affinity level.

Signed-off-by: Anup Patel <anup.patel@linaro.org>
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 50 insertions, 2 deletions

diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
index 59362131b79f..3b6a0cf25c7d 100644
--- a/arch/arm/kvm/psci.c
+++ b/arch/arm/kvm/psci.c
@@ -27,6 +27,16 @@
  * as described in ARM document number ARM DEN 0022A.
  */
 
+#define AFFINITY_MASK(level)    ~((0x1UL << ((level) * MPIDR_LEVEL_BITS)) - 1)
+
+static unsigned long psci_affinity_mask(unsigned long affinity_level)
+{
+        if (affinity_level <= 3)
+                return MPIDR_HWID_BITMASK & AFFINITY_MASK(affinity_level);
+
+        return 0;
+}
+
 static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
 {
         vcpu->arch.pause = true;
@@ -85,6 +95,42 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
         return PSCI_RET_SUCCESS;
 }
 
+static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
+{
+        int i;
+        unsigned long mpidr;
+        unsigned long target_affinity;
+        unsigned long target_affinity_mask;
+        unsigned long lowest_affinity_level;
+        struct kvm *kvm = vcpu->kvm;
+        struct kvm_vcpu *tmp;
+
+        target_affinity = *vcpu_reg(vcpu, 1);
+        lowest_affinity_level = *vcpu_reg(vcpu, 2);
+
+        /* Determine target affinity mask */
+        target_affinity_mask = psci_affinity_mask(lowest_affinity_level);
+        if (!target_affinity_mask)
+                return PSCI_RET_INVALID_PARAMS;
+
+        /* Ignore other bits of target affinity */
+        target_affinity &= target_affinity_mask;
+
+        /*
+         * If one or more VCPU matching target affinity are running
+         * then ON else OFF
+         */
+        kvm_for_each_vcpu(i, tmp, kvm) {
+                mpidr = kvm_vcpu_get_mpidr(tmp);
+                if (((mpidr & target_affinity_mask) == target_affinity) &&
+                    !tmp->arch.pause) {
+                        return PSCI_0_2_AFFINITY_LEVEL_ON;
+                }
+        }
+
+        return PSCI_0_2_AFFINITY_LEVEL_OFF;
+}
+
 static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
 {
         memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
@@ -132,6 +178,10 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
         case PSCI_0_2_FN64_CPU_ON:
                 val = kvm_psci_vcpu_on(vcpu);
                 break;
+        case PSCI_0_2_FN_AFFINITY_INFO:
+        case PSCI_0_2_FN64_AFFINITY_INFO:
+                val = kvm_psci_vcpu_affinity_info(vcpu);
+                break;
         case PSCI_0_2_FN_SYSTEM_OFF:
                 kvm_psci_system_off(vcpu);
                 /*
@@ -157,12 +207,10 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu)
                 ret = 0;
                 break;
         case PSCI_0_2_FN_CPU_SUSPEND:
-        case PSCI_0_2_FN_AFFINITY_INFO:
         case PSCI_0_2_FN_MIGRATE:
         case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
         case PSCI_0_2_FN_MIGRATE_INFO_UP_CPU:
         case PSCI_0_2_FN64_CPU_SUSPEND:
-        case PSCI_0_2_FN64_AFFINITY_INFO:
         case PSCI_0_2_FN64_MIGRATE:
         case PSCI_0_2_FN64_MIGRATE_INFO_UP_CPU:
                 val = PSCI_RET_NOT_SUPPORTED;