KVM: Fix hotplug of CPUs

Both VMX and SVM require per-cpu memory allocation, which is done at module
init time, for only online cpus.

Backend was not allocating enough structure for all possible CPUs, so
new CPUs coming online could not be hardware enabled.
Signed-off-by: Zachary Amsden <zamsden@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/x86/kvm/svm.c

@@ -482,7 +482,7 @@ static __init int svm_hardware_setup(void)
 		kvm_enable_efer_bits(EFER_SVME);
 	}
 
-	for_each_online_cpu(cpu) {
+	for_each_possible_cpu(cpu) {
 		r = svm_cpu_init(cpu);
 		if (r)
 			goto err;
@@ -516,7 +516,7 @@ static __exit void svm_hardware_unsetup(void)
 {
 	int cpu;
 
-	for_each_online_cpu(cpu)
+	for_each_possible_cpu(cpu)
 		svm_cpu_uninit(cpu);
 
 	__free_pages(pfn_to_page(iopm_base >> PAGE_SHIFT), IOPM_ALLOC_ORDER);

arch/x86/kvm/vmx.c

@@ -1350,15 +1350,17 @@ static void free_kvm_area(void)
 {
 	int cpu;
 
-	for_each_online_cpu(cpu)
+	for_each_possible_cpu(cpu) {
 		free_vmcs(per_cpu(vmxarea, cpu));
+		per_cpu(vmxarea, cpu) = NULL;
+	}
 }
 
 static __init int alloc_kvm_area(void)
 {
 	int cpu;
 
-	for_each_online_cpu(cpu) {
+	for_each_possible_cpu(cpu) {
 		struct vmcs *vmcs;
 
 		vmcs = alloc_vmcs_cpu(cpu);