Commit b1bba80a authored by Stefano Garzarella's avatar Stefano Garzarella Committed by David S. Miller
Browse files

vsock/vmci: register vmci_transport only when VMCI guest/host are active 



To allow other transports to be loaded with vmci_transport,
we register the vmci_transport as G2H or H2G only when a VMCI guest
or host is active.

To do that, this patch adds a callback registered in the vmci driver
that will be called when the host or guest becomes active.
This callback will register the vmci_transport in the VSOCK core.

Cc: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c0cfa2d8

drivers/misc/vmw_vmci/vmci_driver.c

+67 −0
Original line number Diff line number Diff line
@@ -28,6 +28,10 @@ MODULE_PARM_DESC(disable_guest, 
static bool vmci_guest_personality_initialized;

static bool vmci_host_personality_initialized;



static DEFINE_MUTEX(vmci_vsock_mutex); /* protects vmci_vsock_transport_cb */

static vmci_vsock_cb vmci_vsock_transport_cb;

bool vmci_vsock_cb_host_called;



/*

 * vmci_get_context_id() - Gets the current context ID.

 *
@@ -45,6 +49,69 @@ u32 vmci_get_context_id(void) 
}

EXPORT_SYMBOL_GPL(vmci_get_context_id);



/*

 * vmci_register_vsock_callback() - Register the VSOCK vmci_transport callback.

 *

 * The callback will be called when the first host or guest becomes active,

 * or if they are already active when this function is called.

 * To unregister the callback, call this function with NULL parameter.

 *

 * Returns 0 on success. -EBUSY if a callback is already registered.

 */

int vmci_register_vsock_callback(vmci_vsock_cb callback)

{

	int err = 0;



	mutex_lock(&vmci_vsock_mutex);



	if (vmci_vsock_transport_cb && callback) {

		err = -EBUSY;

		goto out;

	}



	vmci_vsock_transport_cb = callback;



	if (!vmci_vsock_transport_cb) {

		vmci_vsock_cb_host_called = false;

		goto out;

	}



	if (vmci_guest_code_active())

		vmci_vsock_transport_cb(false);



	if (vmci_host_users() > 0) {

		vmci_vsock_cb_host_called = true;

		vmci_vsock_transport_cb(true);

	}



out:

	mutex_unlock(&vmci_vsock_mutex);

	return err;

}

EXPORT_SYMBOL_GPL(vmci_register_vsock_callback);



void vmci_call_vsock_callback(bool is_host)

{

	mutex_lock(&vmci_vsock_mutex);



	if (!vmci_vsock_transport_cb)

		goto out;



	/* In the host, this function could be called multiple times,

	 * but we want to register it only once.

	 */

	if (is_host) {

		if (vmci_vsock_cb_host_called)

			goto out;



		vmci_vsock_cb_host_called = true;

	}



	vmci_vsock_transport_cb(is_host);

out:

	mutex_unlock(&vmci_vsock_mutex);

}



static int __init vmci_drv_init(void)

{

	int vmci_err;

drivers/misc/vmw_vmci/vmci_driver.h

+2 −0
Original line number Diff line number Diff line
@@ -36,10 +36,12 @@ extern struct pci_dev *vmci_pdev; 


u32 vmci_get_context_id(void);

int vmci_send_datagram(struct vmci_datagram *dg);

void vmci_call_vsock_callback(bool is_host);



int vmci_host_init(void);

void vmci_host_exit(void);

bool vmci_host_code_active(void);

int vmci_host_users(void);



int vmci_guest_init(void);

void vmci_guest_exit(void);

drivers/misc/vmw_vmci/vmci_guest.c

+2 −0
Original line number Diff line number Diff line
@@ -637,6 +637,8 @@ static int vmci_guest_probe_device(struct pci_dev *pdev, 
		  vmci_dev->iobase + VMCI_CONTROL_ADDR);



	pci_set_drvdata(pdev, vmci_dev);



	vmci_call_vsock_callback(false);

	return 0;



err_free_irq:

drivers/misc/vmw_vmci/vmci_host.c

+7 −0
Original line number Diff line number Diff line
@@ -108,6 +108,11 @@ bool vmci_host_code_active(void) 
	     atomic_read(&vmci_host_active_users) > 0);

}



int vmci_host_users(void)

{

	return atomic_read(&vmci_host_active_users);

}



/*

 * Called on open of /dev/vmci.

 */
@@ -338,6 +343,8 @@ static int vmci_host_do_init_context(struct vmci_host_dev *vmci_host_dev, 
	vmci_host_dev->ct_type = VMCIOBJ_CONTEXT;

	atomic_inc(&vmci_host_active_users);



	vmci_call_vsock_callback(true);



	retval = 0;



out:

include/linux/vmw_vmci_api.h

+2 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
struct msghdr;

typedef void (vmci_device_shutdown_fn) (void *device_registration,

					void *user_data);

typedef void (*vmci_vsock_cb) (bool is_host);



int vmci_datagram_create_handle(u32 resource_id, u32 flags,

				vmci_datagram_recv_cb recv_cb,
@@ -37,6 +38,7 @@ int vmci_doorbell_destroy(struct vmci_handle handle); 
int vmci_doorbell_notify(struct vmci_handle handle, u32 priv_flags);

u32 vmci_get_context_id(void);

bool vmci_is_context_owner(u32 context_id, kuid_t uid);

int vmci_register_vsock_callback(vmci_vsock_cb callback);



int vmci_event_subscribe(u32 event,

			 vmci_event_cb callback, void *callback_data,