kvm tools: Add arch-specific KVM_RUN exit handling via kvm_cpu__handle_exit()

This patch creates a new function in x86/kvm-cpu.c, kvm_cpu__handle_exit(), in
which arch-specific exit reasons can be handled outside of the common runloop.

Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

include/kvm/kvm-cpu.h

@@ -2,6 +2,7 @@
 #define KVM__KVM_CPU_H
 
 #include "kvm/kvm-cpu-arch.h"
+#include <stdbool.h>
 
 struct kvm_cpu *kvm_cpu__init(struct kvm *kvm, unsigned long cpu_id);
 void kvm_cpu__delete(struct kvm_cpu *vcpu);
@@ -11,6 +12,7 @@ void kvm_cpu__enable_singlestep(struct kvm_cpu *vcpu);
 void kvm_cpu__run(struct kvm_cpu *vcpu);
 void kvm_cpu__reboot(void);
 int kvm_cpu__start(struct kvm_cpu *cpu);
+bool kvm_cpu__handle_exit(struct kvm_cpu *vcpu);
 
 int kvm_cpu__get_debug_fd(void);
 void kvm_cpu__set_debug_fd(int fd);

kvm-cpu.c

@@ -137,8 +137,14 @@ int kvm_cpu__start(struct kvm_cpu *cpu)
 			goto exit_kvm;
 		case KVM_EXIT_SHUTDOWN:
 			goto exit_kvm;
-		default:
-			goto panic_kvm;
+		default: {
+			bool ret;
+
+			ret = kvm_cpu__handle_exit(cpu);
+			if (!ret)
+				goto panic_kvm;
+			break;
+		}
 		}
 		kvm_cpu__handle_coalesced_mmio(cpu);
 	}

x86/kvm-cpu.c

@@ -212,6 +212,11 @@ void kvm_cpu__reset_vcpu(struct kvm_cpu *vcpu)
 	kvm_cpu__setup_msrs(vcpu);
 }
 
+bool kvm_cpu__handle_exit(struct kvm_cpu *vcpu)
+{
+	return false;
+}
+
 static void print_dtable(const char *name, struct kvm_dtable *dtable)
 {
 	dprintf(debug_fd, " %s                 %016llx  %08hx\n",