xen: import a proper event channel user-space device

The user-space event channel device is used by applications to receive
and send event channel interrupts. This device is based on the Linux
evtchn device.

Sponsored by: Citrix Systems R&D

xen/evtchn/evtchn_dev.c:
 - Remove the old event channel device, which was already disabled in
   the build system.

dev/xen/evtchn/evtchn_dev.c:
 - Import a new event channel device based on the one present in
   Linux.
 - This device allows the following operations:
   - Bind VIRQ event channels (ioctl).
   - Bind regular event channels (ioctl).
   - Create and bind new event channels (ioctl).
   - Unbind event channels (ioctl).
   - Send notifications to event channels (ioctl).
   - Reset the device shared memory ring (ioctl).
   - Unmask event channels (write).
   - Receive event channel upcalls (read).
 - The new code is MP safe, and can be used concurrently.

conf/files:
 - Add the new device to the build system.

1 files changed, 0 insertions, 358 deletions

diff --git a/sys/xen/evtchn/evtchn_dev.c b/sys/xen/evtchn/evtchn_dev.c
deleted file mode 100644
index 9da2642..0000000
--- a/sys/xen/evtchn/evtchn_dev.c
+++ /dev/null
@@ -1,358 +0,0 @@
-/******************************************************************************
- * evtchn.c
- * 
- * Xenolinux driver for receiving and demuxing event-channel signals.
- * 
- * Copyright (c) 2004, K A Fraser
- */
-
-#include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
-
-#include <sys/param.h>
-#include <sys/systm.h>
-#include <sys/uio.h>
-#include <sys/bus.h>
-#include <sys/malloc.h>
-#include <sys/kernel.h>
-#include <sys/lock.h>
-#include <sys/mutex.h>
-#include <sys/selinfo.h>
-#include <sys/poll.h>
-#include <sys/conf.h>
-#include <sys/fcntl.h>
-#include <sys/ioccom.h>
-#include <sys/rman.h>
-
-#include <xen/xen-os.h>
-#include <xen/evtchn.h>
-#include <xen/xen_intr.h>
-
-#include <machine/bus.h>
-#include <machine/resource.h>
-#include <machine/xen/synch_bitops.h>
-
-#include <xen/evtchn/evtchnvar.h>
-
-typedef struct evtchn_sotfc {
-
-	struct selinfo  ev_rsel;
-} evtchn_softc_t;
-
-/* Only one process may open /dev/xen/evtchn at any time. */
-static unsigned long evtchn_dev_inuse;
-
-/* Notification ring, accessed via /dev/xen/evtchn. */
-
-#define EVTCHN_RING_SIZE     2048  /* 2048 16-bit entries */
-
-#define EVTCHN_RING_MASK(_i) ((_i)&(EVTCHN_RING_SIZE-1))
-static uint16_t *ring;
-static unsigned int ring_cons, ring_prod, ring_overflow;
-
-/* Which ports is user-space bound to? */
-static uint32_t bound_ports[32];
-
-/* Unique address for processes to sleep on */
-static void *evtchn_waddr = &ring;
-
-static struct mtx lock, upcall_lock;
-
-static d_read_t      evtchn_read;
-static d_write_t     evtchn_write;
-static d_ioctl_t     evtchn_ioctl;
-static d_poll_t      evtchn_poll;
-static d_open_t      evtchn_open;
-static d_close_t     evtchn_close;
-
-
-void 
-evtchn_device_upcall(evtchn_port_t port)
-{
-	mtx_lock(&upcall_lock);
-
-	evtchn_mask_port(port);
-	evtchn_clear_port(port);
-
-	if ( ring != NULL ) {
-		if ( (ring_prod - ring_cons) < EVTCHN_RING_SIZE ) {
-			ring[EVTCHN_RING_MASK(ring_prod)] = (uint16_t)port;
-			if ( ring_cons == ring_prod++ ) {
-				wakeup(evtchn_waddr);
-			}
-		}
-		else {
-			ring_overflow = 1;
-		}
-	}
-
-	mtx_unlock(&upcall_lock);
-}
-
-static void 
-__evtchn_reset_buffer_ring(void)
-{
-	/* Initialise the ring to empty. Clear errors. */
-	ring_cons = ring_prod = ring_overflow = 0;
-}
-
-static int
-evtchn_read(struct cdev *dev, struct uio *uio, int ioflag)
-{
-	int rc;
-	unsigned int count, c, p, sst = 0, bytes1 = 0, bytes2 = 0;
-	count = uio->uio_resid;
-    
-	count &= ~1; /* even number of bytes */
-
-	if ( count == 0 )
-	{
-		rc = 0;
-		goto out;
-	}
-
-	if ( count > PAGE_SIZE )
-		count = PAGE_SIZE;
-
-	for ( ; ; ) {
-		if ( (c = ring_cons) != (p = ring_prod) )
-			break;
-
-		if ( ring_overflow ) {
-			rc = EFBIG;
-			goto out;
-		}
-
-		if (sst != 0) {
-			rc = EINTR;
-			goto out;
-		}
-
-		/* PCATCH == check for signals before and after sleeping 
-		 * PWAIT == priority of waiting on resource 
-		 */
-		sst = tsleep(evtchn_waddr, PWAIT|PCATCH, "evchwt", 10);
-	}
-
-	/* Byte lengths of two chunks. Chunk split (if any) is at ring wrap. */
-	if ( ((c ^ p) & EVTCHN_RING_SIZE) != 0 ) {
-		bytes1 = (EVTCHN_RING_SIZE - EVTCHN_RING_MASK(c)) * sizeof(uint16_t);
-		bytes2 = EVTCHN_RING_MASK(p) * sizeof(uint16_t);
-	}
-	else {
-		bytes1 = (p - c) * sizeof(uint16_t);
-		bytes2 = 0;
-	}
-
-	/* Truncate chunks according to caller's maximum byte count. */
-	if ( bytes1 > count ) {
-		bytes1 = count;
-		bytes2 = 0;
-	}
-	else if ( (bytes1 + bytes2) > count ) {
-		bytes2 = count - bytes1;
-	}
-    
-	if ( uiomove(&ring[EVTCHN_RING_MASK(c)], bytes1, uio) ||
-	     ((bytes2 != 0) && uiomove(&ring[0], bytes2, uio)))
-		/* keeping this around as its replacement is not equivalent 
-		 * copyout(&ring[0], &buf[bytes1], bytes2) 
-		 */
-	{
-		rc = EFAULT;
-		goto out;
-	}
-
-	ring_cons += (bytes1 + bytes2) / sizeof(uint16_t);
-
-	rc = bytes1 + bytes2;
-
- out:
-    
-	return rc;
-}
-
-static int 
-evtchn_write(struct cdev *dev, struct uio *uio, int ioflag)
-{
-	int  rc, i, count;
-    
-	count = uio->uio_resid;
-    
-	uint16_t *kbuf = (uint16_t *)malloc(PAGE_SIZE, M_DEVBUF, M_WAITOK);
-
-
-	if ( kbuf == NULL )
-		return ENOMEM;
-
-	count &= ~1; /* even number of bytes */
-
-	if ( count == 0 ) {
-		rc = 0;
-		goto out;
-	}
-
-	if ( count > PAGE_SIZE )
-		count = PAGE_SIZE;
-
-	if ( uiomove(kbuf, count, uio) != 0 ) {
-		rc = EFAULT;
-		goto out;
-	}
-
-	mtx_lock_spin(&lock);
-	for ( i = 0; i < (count/2); i++ )
-		if ( test_bit(kbuf[i], &bound_ports[0]) )
-			evtchn_unmask_port(kbuf[i]);
-	mtx_unlock_spin(&lock);
-
-	rc = count;
-
- out:
-	free(kbuf, M_DEVBUF);
-	return rc;
-}
-
-static int 
-evtchn_ioctl(struct cdev *dev, unsigned long cmd, caddr_t arg, 
-	     int mode, struct thread *td __unused)
-{
-	int rc = 0;
-    
-#ifdef NOTYET
-	mtx_lock_spin(&lock);
-    
-	switch ( cmd )
-	{
-	case EVTCHN_RESET:
-		__evtchn_reset_buffer_ring();
-		break;
-	case EVTCHN_BIND:
-		if ( !synch_test_and_set_bit((uintptr_t)arg, &bound_ports[0]) )
-			unmask_evtchn((uintptr_t)arg);
-		else
-			rc = EINVAL;
-		break;
-	case EVTCHN_UNBIND:
-		if ( synch_test_and_clear_bit((uintptr_t)arg, &bound_ports[0]) )
-			mask_evtchn((uintptr_t)arg);
-		else
-			rc = EINVAL;
-		break;
-	default:
-		rc = ENOSYS;
-		break;
-	}
-
-	mtx_unlock_spin(&lock);   
-#endif
-
-	return rc;
-}
-
-static int
-evtchn_poll(struct cdev *dev, int poll_events, struct thread *td)
-{
-
-	evtchn_softc_t *sc;
-	unsigned int mask = POLLOUT | POLLWRNORM;
-    
-	sc = dev->si_drv1;
-    
-	if ( ring_cons != ring_prod )
-		mask |= POLLIN | POLLRDNORM;
-	else if ( ring_overflow )
-		mask = POLLERR;
-	else
-		selrecord(td, &sc->ev_rsel);
-
-
-	return mask;
-}
-
-
-static int 
-evtchn_open(struct cdev *dev, int flag, int otyp, struct thread *td)
-{
-	uint16_t *_ring;
-    
-	if (flag & O_NONBLOCK)
-		return EBUSY;
-
-	if ( synch_test_and_set_bit(0, &evtchn_dev_inuse) )
-		return EBUSY;
-
-	if ( (_ring = (uint16_t *)malloc(PAGE_SIZE, M_DEVBUF, M_WAITOK)) == NULL )
-		return ENOMEM;
-
-	mtx_lock_spin(&lock);
-	ring = _ring;
-	__evtchn_reset_buffer_ring();
-	mtx_unlock_spin(&lock);
-
-
-	return 0;
-}
-
-static int 
-evtchn_close(struct cdev *dev, int flag, int otyp, struct thread *td __unused)
-{
-	int i;
-
-	if (ring != NULL) {
-		free(ring, M_DEVBUF);
-		ring = NULL;
-	}
-	mtx_lock_spin(&lock);
-	for ( i = 0; i < NR_EVENT_CHANNELS; i++ )
-		if ( synch_test_and_clear_bit(i, &bound_ports[0]) )
-			evtchn_mask_port(i);
-	mtx_unlock_spin(&lock);
-
-	evtchn_dev_inuse = 0;
-
-	return 0;
-}
-
-static struct cdevsw evtchn_devsw = {
-	.d_version =	D_VERSION,
-	.d_open =	evtchn_open,
-	.d_close =	evtchn_close,
-	.d_read =	evtchn_read,
-	.d_write =	evtchn_write,
-	.d_ioctl =	evtchn_ioctl,
-	.d_poll =	evtchn_poll,
-	.d_name =	"evtchn",
-};
-
-
-/* XXX  - if this device is ever supposed to support use by more than one process
- * this global static will have to go away
- */
-static struct cdev *evtchn_dev;
-
-
-
-static int 
-evtchn_dev_init(void *dummy __unused)
-{
-	/* XXX I believe we don't need these leaving them here for now until we 
-	 * have some semblance of it working 
-	 */
-	mtx_init(&upcall_lock, "evtchup", NULL, MTX_DEF);
-
-	/* (DEVFS) create '/dev/misc/evtchn'. */
-	evtchn_dev = make_dev(&evtchn_devsw, 0, UID_ROOT, GID_WHEEL, 0600, "xen/evtchn");
-
-	mtx_init(&lock, "evch", NULL, MTX_SPIN | MTX_NOWITNESS);
-
-	evtchn_dev->si_drv1 = malloc(sizeof(evtchn_softc_t), M_DEVBUF, M_WAITOK);
-	bzero(evtchn_dev->si_drv1, sizeof(evtchn_softc_t));
-
-	if (bootverbose)
-		printf("Event-channel device installed.\n");
-
-	return 0;
-}
-
-SYSINIT(evtchn_dev_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, evtchn_dev_init, NULL);