ARM/ARM64: KVM: Fix CPU_ON emulation for PSCI v0.2

As-per PSCI v0.2, the source CPU provides physical address of
"entry point" and "context id" for starting a target CPU. Also,
if target CPU is already running then we should return ALREADY_ON.

Current emulation of CPU_ON function does not consider physical
address of "context id" and returns INVALID_PARAMETERS if target
CPU is already running.

This patch updates kvm_psci_vcpu_on() such that it works for both
PSCI v0.1 and PSCI v0.2.

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>

diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c
index cce901a510fa37ef1f2448c35ba7e266b8ab5048..1067579c733654408806b52c80f43214c1a3f37e 100644 (file)
--- a/arch/arm/kvm/psci.c
+++ b/arch/arm/kvm/psci.c
@@ -48,6 +48,7 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
        struct kvm_vcpu *vcpu = NULL, *tmp;
        wait_queue_head_t *wq;
        unsigned long cpu_id;
+       unsigned long context_id;
        unsigned long mpidr;
        phys_addr_t target_pc;
        int i;
@@ -68,10 +69,17 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
         * Make sure the caller requested a valid CPU and that the CPU is
         * turned off.
         */
-       if (!vcpu || !vcpu->arch.pause)
+       if (!vcpu)
                return PSCI_RET_INVALID_PARAMS;
+       if (!vcpu->arch.pause) {
+               if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1)
+                       return PSCI_RET_ALREADY_ON;
+               else
+                       return PSCI_RET_INVALID_PARAMS;
+       }
 
        target_pc = *vcpu_reg(source_vcpu, 2);
+       context_id = *vcpu_reg(source_vcpu, 3);
 
        kvm_reset_vcpu(vcpu);
 
@@ -86,6 +94,11 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
                kvm_vcpu_set_be(vcpu);
 
        *vcpu_pc(vcpu) = target_pc;
+       /*
+        * NOTE: We always update r0 (or x0) because for PSCI v0.1
+        * the general puspose registers are undefined upon CPU_ON.
+        */
+       *vcpu_reg(vcpu, 0) = context_id;
        vcpu->arch.pause = false;
        smp_mb();               /* Make sure the above is visible */