KVM: Make the supported cpuid list a host property rather than a vm property

One of the use cases for the supported cpuid list is to create a "greatest
common denominator" of cpu capabilities in a server farm.  As such, it is
useful to be able to get the list without creating a virtual machine first.

Since the code does not depend on the vm in any way, all that is needed is
to move it to the device ioctl handler.  The capability identifier is also
changed so that binaries made against -rc1 will fail gracefully.
Signed-off-by: Avi Kivity <avi@qumranet.com>

arch/x86/kvm/x86.c

@@ -46,6 +46,9 @@
 #define VM_STAT(x) offsetof(struct kvm, stat.x), KVM_STAT_VM
 #define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU
 
+static int kvm_dev_ioctl_get_supported_cpuid(struct kvm_cpuid2 *cpuid,
+				    struct kvm_cpuid_entry2 __user *entries);
+
 struct kvm_x86_ops *kvm_x86_ops;
 
 struct kvm_stats_debugfs_item debugfs_entries[] = {
@@ -727,6 +730,24 @@ long kvm_arch_dev_ioctl(struct file *filp,
 		r = 0;
 		break;
 	}
+	case KVM_GET_SUPPORTED_CPUID: {
+		struct kvm_cpuid2 __user *cpuid_arg = argp;
+		struct kvm_cpuid2 cpuid;
+
+		r = -EFAULT;
+		if (copy_from_user(&cpuid, cpuid_arg, sizeof cpuid))
+			goto out;
+		r = kvm_dev_ioctl_get_supported_cpuid(&cpuid,
+			cpuid_arg->entries);
+		if (r)
+			goto out;
+
+		r = -EFAULT;
+		if (copy_to_user(cpuid_arg, &cpuid, sizeof cpuid))
+			goto out;
+		r = 0;
+		break;
+	}
 	default:
 		r = -EINVAL;
 	}
@@ -974,8 +995,7 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 	put_cpu();
 }
 
-static int kvm_vm_ioctl_get_supported_cpuid(struct kvm *kvm,
-				    struct kvm_cpuid2 *cpuid,
+static int kvm_dev_ioctl_get_supported_cpuid(struct kvm_cpuid2 *cpuid,
 				    struct kvm_cpuid_entry2 __user *entries)
 {
 	struct kvm_cpuid_entry2 *cpuid_entries;
@@ -1487,24 +1507,6 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		r = 0;
 		break;
 	}
-	case KVM_GET_SUPPORTED_CPUID: {
-		struct kvm_cpuid2 __user *cpuid_arg = argp;
-		struct kvm_cpuid2 cpuid;
-
-		r = -EFAULT;
-		if (copy_from_user(&cpuid, cpuid_arg, sizeof cpuid))
-			goto out;
-		r = kvm_vm_ioctl_get_supported_cpuid(kvm, &cpuid,
-			cpuid_arg->entries);
-		if (r)
-			goto out;
-
-		r = -EFAULT;
-		if (copy_to_user(cpuid_arg, &cpuid, sizeof cpuid))
-			goto out;
-		r = 0;
-		break;
-	}
 	default:
 		;
 	}

include/linux/kvm.h

@@ -221,6 +221,7 @@ struct kvm_vapic_addr {
  * Get size for mmap(vcpu_fd)
  */
 #define KVM_GET_VCPU_MMAP_SIZE    _IO(KVMIO,   0x04) /* in bytes */
+#define KVM_GET_SUPPORTED_CPUID   _IOWR(KVMIO, 0x05, struct kvm_cpuid2)
 
 /*
  * Extension capability list.
@@ -230,8 +231,8 @@ struct kvm_vapic_addr {
 #define KVM_CAP_MMU_SHADOW_CACHE_CONTROL 2
 #define KVM_CAP_USER_MEMORY 3
 #define KVM_CAP_SET_TSS_ADDR 4
-#define KVM_CAP_EXT_CPUID 5
 #define KVM_CAP_VAPIC 6
+#define KVM_CAP_EXT_CPUID 7
 
 /*
  * ioctls for VM fds
@@ -249,7 +250,6 @@ struct kvm_vapic_addr {
 #define KVM_CREATE_VCPU           _IO(KVMIO,  0x41)
 #define KVM_GET_DIRTY_LOG         _IOW(KVMIO, 0x42, struct kvm_dirty_log)
 #define KVM_SET_MEMORY_ALIAS      _IOW(KVMIO, 0x43, struct kvm_memory_alias)
-#define KVM_GET_SUPPORTED_CPUID   _IOWR(KVMIO, 0x48, struct kvm_cpuid2)
 /* Device model IOC */
 #define KVM_CREATE_IRQCHIP	  _IO(KVMIO,  0x60)
 #define KVM_IRQ_LINE		  _IOW(KVMIO, 0x61, struct kvm_irq_level)