[RFC v4 11/13] kvm: arm: implement kvm_arch_halt_guest and kvm_arch_resume_guest

[Eric Auger]

This patch defines __KVM_HAVE_ARCH_HALT_GUEST and implements
kvm_arch_halt_guest and kvm_arch_resume_guest for ARM.

On halt, the guest is forced to exit and prevented from being
re-entered.

Signed-off-by: Eric Auger <eric.auger at linaro.org>
---
 arch/arm/include/asm/kvm_host.h |  4 ++++
 arch/arm/kvm/arm.c              | 32 +++++++++++++++++++++++++++++---
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 87f0921..a9f2c31 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -28,6 +28,7 @@
 #include <kvm/arm_arch_timer.h>
 
 #define __KVM_HAVE_ARCH_INTC_INITIALIZED
+#define __KVM_HAVE_ARCH_HALT_GUEST
 
 #if defined(CONFIG_KVM_ARM_MAX_VCPUS)
 #define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS
@@ -131,6 +132,9 @@ struct kvm_vcpu_arch {
 	/* vcpu power-off state*/
 	bool power_off;
 
+	/* Don't run the guest */
+	bool pause;
+
 	/* IO related fields */
 	struct kvm_decode mmio_decode;
 
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 6f63ab7..6c743a1 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -455,11 +455,36 @@ bool kvm_arch_intc_initialized(struct kvm *kvm)
 	return vgic_initialized(kvm);
 }
 
+void kvm_arch_halt_guest(struct kvm *kvm)
+{
+	int i;
+	struct kvm_vcpu *vcpu;
+
+	kvm_for_each_vcpu(i, vcpu, kvm)
+		vcpu->arch.pause = true;
+	force_vm_exit(cpu_all_mask);
+}
+
+void kvm_arch_resume_guest(struct kvm *kvm)
+{
+	int i;
+	struct kvm_vcpu *vcpu;
+
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		wait_queue_head_t *wq = kvm_arch_vcpu_wq(vcpu);
+
+		vcpu->arch.pause = false;
+		wake_up_interruptible(wq);
+	}
+}
+
+
 static void vcpu_pause(struct kvm_vcpu *vcpu)
 {
 	wait_queue_head_t *wq = kvm_arch_vcpu_wq(vcpu);
 
-	wait_event_interruptible(*wq, !vcpu->arch.power_off);
+	wait_event_interruptible(*wq, ((!vcpu->arch.power_off) &&
+				       (!vcpu->arch.pause)));
 }
 
 static int kvm_vcpu_initialized(struct kvm_vcpu *vcpu)
@@ -509,7 +534,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 
 		update_vttbr(vcpu->kvm);
 
-		if (vcpu->arch.power_off)
+		if (vcpu->arch.power_off || vcpu->arch.pause)
 			vcpu_pause(vcpu);
 
 		kvm_vgic_flush_hwstate(vcpu);
@@ -527,7 +552,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 			run->exit_reason = KVM_EXIT_INTR;
 		}
 
-		if (ret <= 0 || need_new_vmid_gen(vcpu->kvm)) {
+		if (ret <= 0 || need_new_vmid_gen(vcpu->kvm) ||
+		    vcpu->arch.pause) {
 			kvm_timer_sync_hwstate(vcpu);
 			local_irq_enable();
 			kvm_timer_finish_sync(vcpu);
-- 
1.9.1