kvm: add device control API

Currently, devices that are emulated inside KVM are configured in a
hardcoded manner based on an assumption that any given architecture
only has one way to do it.  If there's any need to access device state,
it is done through inflexible one-purpose-only IOCTLs (e.g.
KVM_GET/SET_LAPIC).  Defining new IOCTLs for every little thing is
cumbersome and depletes a limited numberspace.

This API provides a mechanism to instantiate a device of a certain
type, returning an ID that can be used to set/get attributes of the
device.  Attributes may include configuration parameters (e.g.
register base address), device state, operational commands, etc.  It
is similar to the ONE_REG API, except that it acts on devices rather
than vcpus.

Both device types and individual attributes can be tested without having
to create the device or get/set the attribute, without the need for
separately managing enumerated capabilities.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

Conflicts:

	include/linux/kvm_host.h
	include/uapi/linux/kvm.h

Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com>

2 files changed, 64 insertions, 0 deletions

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 5c2561e..c1b0e1a 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -995,6 +995,41 @@ static inline bool kvm_check_request(int req, struct kvm_vcpu *vcpu)
 	}
 }
 
+struct kvm_device_ops;
+
+struct kvm_device {
+	struct kvm_device_ops *ops;
+	struct kvm *kvm;
+	atomic_t users;
+	void *private;
+};
+
+/* create, destroy, and name are mandatory */
+struct kvm_device_ops {
+	const char *name;
+	int (*create)(struct kvm_device *dev, u32 type);
+
+	/*
+	 * Destroy is responsible for freeing dev.
+	 *
+	 * Destroy may be called before or after destructors are called
+	 * on emulated I/O regions, depending on whether a reference is
+	 * held by a vcpu or other kvm component that gets destroyed
+	 * after the emulated I/O.
+	 */
+	void (*destroy)(struct kvm_device *dev);
+
+	int (*set_attr)(struct kvm_device *dev, struct kvm_device_attr *attr);
+	int (*get_attr)(struct kvm_device *dev, struct kvm_device_attr *attr);
+	int (*has_attr)(struct kvm_device *dev, struct kvm_device_attr *attr);
+	long (*ioctl)(struct kvm_device *dev, unsigned int ioctl,
+		      unsigned long arg);
+};
+
+void kvm_device_get(struct kvm_device *dev);
+void kvm_device_put(struct kvm_device *dev);
+struct kvm_device *kvm_device_from_filp(struct file *filp);
+
 #ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
 
 static inline void kvm_vcpu_set_in_spin_loop(struct kvm_vcpu *vcpu, bool val)
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 6fa7ee2..7feab9e 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -639,6 +639,9 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_PPC_BOOKE_WATCHDOG 83
 #define KVM_CAP_PPC_HTAB_FD 84
 #define KVM_CAP_PPC_EPR 86
+#define KVM_CAP_ARM_PSCI 87
+#define KVM_CAP_ARM_SET_DEVICE_ADDR 88
+#define KVM_CAP_DEVICE_CTRL 89
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -782,6 +785,24 @@ struct kvm_msi {
 };
 
 /*
+ * Device control API, available with KVM_CAP_DEVICE_CTRL
+ */
+#define KVM_CREATE_DEVICE_TEST		1
+
+struct kvm_create_device {
+	__u32	type;	/* in: KVM_DEV_TYPE_xxx */
+	__u32	fd;	/* out: device handle */
+	__u32	flags;	/* in: KVM_CREATE_DEVICE_xxx */
+};
+
+struct kvm_device_attr {
+	__u32	flags;		/* no flags currently defined */
+	__u32	group;		/* device-defined */
+	__u64	attr;		/* group-defined */
+	__u64	addr;		/* userspace address of attr data */
+};
+
+/*
  * ioctls for VM fds
  */
 #define KVM_SET_MEMORY_REGION     _IOW(KVMIO,  0x40, struct kvm_memory_region)
@@ -867,6 +888,14 @@ struct kvm_s390_ucas_mapping {
 /* Available with KVM_CAP_PPC_HTAB_FD */
 #define KVM_PPC_GET_HTAB_FD	  _IOW(KVMIO,  0xaa, struct kvm_get_htab_fd)
 
+/* ioctl for vm fd */
+#define KVM_CREATE_DEVICE	  _IOWR(KVMIO,  0xe0, struct kvm_create_device)
+
+/* ioctls for fds returned by KVM_CREATE_DEVICE */
+#define KVM_SET_DEVICE_ATTR	  _IOW(KVMIO,  0xe1, struct kvm_device_attr)
+#define KVM_GET_DEVICE_ATTR	  _IOW(KVMIO,  0xe2, struct kvm_device_attr)
+#define KVM_HAS_DEVICE_ATTR	  _IOW(KVMIO,  0xe3, struct kvm_device_attr)
+
 /*
  * ioctls for vcpu fds
  */