freebsd-nq/sys/xen/evtchn/evtchn_dev.c
Justin T. Gibbs 76acc41fb7 Implement vector callback for PVHVM and unify event channel implementations
Re-structure Xen HVM support so that:
	- Xen is detected and hypercalls can be performed very
	  early in system startup.
	- Xen interrupt services are implemented using FreeBSD's native
	  interrupt delivery infrastructure.
	- the Xen interrupt service implementation is shared between PV
	  and HVM guests.
	- Xen interrupt handlers can optionally use a filter handler
	  in order to avoid the overhead of dispatch to an interrupt
	  thread.
	- interrupt load can be distributed among all available CPUs.
	- the overhead of accessing the emulated local and I/O apics
	  on HVM is removed for event channel port events.
	- a similar optimization can eventually, and fairly easily,
	  be used to optimize MSI.

Early Xen detection, HVM refactoring, PVHVM interrupt infrastructure,
and misc Xen cleanups:

Sponsored by: Spectra Logic Corporation

Unification of PV & HVM interrupt infrastructure, bug fixes,
and misc Xen cleanups:

Submitted by: Roger Pau Monné
Sponsored by: Citrix Systems R&D

sys/x86/x86/local_apic.c:
sys/amd64/include/apicvar.h:
sys/i386/include/apicvar.h:
sys/amd64/amd64/apic_vector.S:
sys/i386/i386/apic_vector.s:
sys/amd64/amd64/machdep.c:
sys/i386/i386/machdep.c:
sys/i386/xen/exception.s:
sys/x86/include/segments.h:
	Reserve IDT vector 0x93 for the Xen event channel upcall
	interrupt handler.  On Hypervisors that support the direct
	vector callback feature, we can request that this vector be
	called directly by an injected HVM interrupt event, instead
	of a simulated PCI interrupt on the Xen platform PCI device.
	This avoids all of the overhead of dealing with the emulated
	I/O APIC and local APIC.  It also means that the Hypervisor
	can inject these events on any CPU, allowing upcalls for
	different ports to be handled in parallel.

sys/amd64/amd64/mp_machdep.c:
sys/i386/i386/mp_machdep.c:
	Map Xen per-vcpu area during AP startup.

sys/amd64/include/intr_machdep.h:
sys/i386/include/intr_machdep.h:
	Increase the FreeBSD IRQ vector table to include space
	for event channel interrupt sources.

sys/amd64/include/pcpu.h:
sys/i386/include/pcpu.h:
	Remove Xen HVM per-cpu variable data.  These fields are now
	allocated via the dynamic per-cpu scheme.  See xen_intr.c
	for details.

sys/amd64/include/xen/hypercall.h:
sys/dev/xen/blkback/blkback.c:
sys/i386/include/xen/xenvar.h:
sys/i386/xen/clock.c:
sys/i386/xen/xen_machdep.c:
sys/xen/gnttab.c:
	Prefer FreeBSD primatives to Linux ones in Xen support code.

sys/amd64/include/xen/xen-os.h:
sys/i386/include/xen/xen-os.h:
sys/xen/xen-os.h:
sys/dev/xen/balloon/balloon.c:
sys/dev/xen/blkback/blkback.c:
sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/console/xencons_ring.c:
sys/dev/xen/control/control.c:
sys/dev/xen/netback/netback.c:
sys/dev/xen/netfront/netfront.c:
sys/dev/xen/xenpci/xenpci.c:
sys/i386/i386/machdep.c:
sys/i386/include/pmap.h:
sys/i386/include/xen/xenfunc.h:
sys/i386/isa/npx.c:
sys/i386/xen/clock.c:
sys/i386/xen/mp_machdep.c:
sys/i386/xen/mptable.c:
sys/i386/xen/xen_clock_util.c:
sys/i386/xen/xen_machdep.c:
sys/i386/xen/xen_rtc.c:
sys/xen/evtchn/evtchn_dev.c:
sys/xen/features.c:
sys/xen/gnttab.c:
sys/xen/gnttab.h:
sys/xen/hvm.h:
sys/xen/xenbus/xenbus.c:
sys/xen/xenbus/xenbus_if.m:
sys/xen/xenbus/xenbusb_front.c:
sys/xen/xenbus/xenbusvar.h:
sys/xen/xenstore/xenstore.c:
sys/xen/xenstore/xenstore_dev.c:
sys/xen/xenstore/xenstorevar.h:
	Pull common Xen OS support functions/settings into xen/xen-os.h.

sys/amd64/include/xen/xen-os.h:
sys/i386/include/xen/xen-os.h:
sys/xen/xen-os.h:
	Remove constants, macros, and functions unused in FreeBSD's Xen
	support.

sys/xen/xen-os.h:
sys/i386/xen/xen_machdep.c:
sys/x86/xen/hvm.c:
	Introduce new functions xen_domain(), xen_pv_domain(), and
	xen_hvm_domain().  These are used in favor of #ifdefs so that
	FreeBSD can dynamically detect and adapt to the presence of
	a hypervisor.  The goal is to have an HVM optimized GENERIC,
	but more is necessary before this is possible.

sys/amd64/amd64/machdep.c:
sys/dev/xen/xenpci/xenpcivar.h:
sys/dev/xen/xenpci/xenpci.c:
sys/x86/xen/hvm.c:
sys/sys/kernel.h:
	Refactor magic ioport, Hypercall table and Hypervisor shared
	information page setup, and move it to a dedicated HVM support
	module.

	HVM mode initialization is now triggered during the
	SI_SUB_HYPERVISOR phase of system startup.  This currently
	occurs just after the kernel VM is fully setup which is
	just enough infrastructure to allow the hypercall table
	and shared info page to be properly mapped.

sys/xen/hvm.h:
sys/x86/xen/hvm.c:
	Add definitions and a method for configuring Hypervisor event
	delievery via a direct vector callback.

sys/amd64/include/xen/xen-os.h:
sys/x86/xen/hvm.c:

sys/conf/files:
sys/conf/files.amd64:
sys/conf/files.i386:
	Adjust kernel build to reflect the refactoring of early
	Xen startup code and Xen interrupt services.

sys/dev/xen/blkback/blkback.c:
sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/blkfront/block.h:
sys/dev/xen/control/control.c:
sys/dev/xen/evtchn/evtchn_dev.c:
sys/dev/xen/netback/netback.c:
sys/dev/xen/netfront/netfront.c:
sys/xen/xenstore/xenstore.c:
sys/xen/evtchn/evtchn_dev.c:
sys/dev/xen/console/console.c:
sys/dev/xen/console/xencons_ring.c
	Adjust drivers to use new xen_intr_*() API.

sys/dev/xen/blkback/blkback.c:
	Since blkback defers all event handling to a taskqueue,
	convert this task queue to a "fast" taskqueue, and schedule
	it via an interrupt filter.  This avoids an unnecessary
	ithread context switch.

sys/xen/xenstore/xenstore.c:
	The xenstore driver is MPSAFE.  Indicate as much when
	registering its interrupt handler.

sys/xen/xenbus/xenbus.c:
sys/xen/xenbus/xenbusvar.h:
	Remove unused event channel APIs.

sys/xen/evtchn.h:
	Remove all kernel Xen interrupt service API definitions
	from this file.  It is now only used for structure and
	ioctl definitions related to the event channel userland
	device driver.

	Update the definitions in this file to match those from
	NetBSD.  Implementing this interface will be necessary for
	Dom0 support.

sys/xen/evtchn/evtchnvar.h:
	Add a header file for implemenation internal APIs related
	to managing event channels event delivery.  This is used
	to allow, for example, the event channel userland device
	driver to access low-level routines that typical kernel
	consumers of event channel services should never access.

sys/xen/interface/event_channel.h:
sys/xen/xen_intr.h:
	Standardize on the evtchn_port_t type for referring to
	an event channel port id.  In order to prevent low-level
	event channel APIs from leaking to kernel consumers who
	should not have access to this data, the type is defined
	twice: Once in the Xen provided event_channel.h, and again
	in xen/xen_intr.h.  The double declaration is protected by
	__XEN_EVTCHN_PORT_DEFINED__ to ensure it is never declared
	twice within a given compilation unit.

sys/xen/xen_intr.h:
sys/xen/evtchn/evtchn.c:
sys/x86/xen/xen_intr.c:
sys/dev/xen/xenpci/evtchn.c:
sys/dev/xen/xenpci/xenpcivar.h:
	New implementation of Xen interrupt services.  This is
	similar in many respects to the i386 PV implementation with
	the exception that events for bound to event channel ports
	(i.e. not IPI, virtual IRQ, or physical IRQ) are further
	optimized to avoid mask/unmask operations that aren't
	necessary for these edge triggered events.

	Stubs exist for supporting physical IRQ binding, but will
	need additional work before this implementation can be
	fully shared between PV and HVM.

sys/amd64/amd64/mp_machdep.c:
sys/i386/i386/mp_machdep.c:
sys/i386/xen/mp_machdep.c
sys/x86/xen/hvm.c:
	Add support for placing vcpu_info into an arbritary memory
	page instead of using HYPERVISOR_shared_info->vcpu_info.
	This allows the creation of domains with more than 32 vcpus.

sys/i386/i386/machdep.c:
sys/i386/xen/clock.c:
sys/i386/xen/xen_machdep.c:
sys/i386/xen/exception.s:
	Add support for new event channle implementation.
2013-08-29 19:52:18 +00:00

359 lines
7.1 KiB
C

/******************************************************************************
* 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);