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events.c
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/*
* Xen event channels
*
* Xen models interrupts with abstract event channels. Because each
* domain gets 1024 event channels, but NR_IRQ is not that large, we
* must dynamically map irqs<->event channels. The event channels
* interface with the rest of the kernel by defining a xen interrupt
* chip. When an event is received, it is mapped to an irq and sent
* through the normal interrupt processing path.
*
* There are four kinds of events which can be mapped to an event
* channel:
*
* 1. Inter-domain notifications. This includes all the virtual
* device events, since they're driven by front-ends in another domain
* (typically dom0).
* 2. VIRQs, typically used for timers. These are per-cpu events.
* 3. IPIs.
* 4. PIRQs - Hardware interrupts.
*
* Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
*/
#include <linux/linkage.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/bootmem.h>
#include <linux/slab.h>
#include <linux/irqnr.h>
#include <linux/pci.h>
#include <asm/desc.h>
#include <asm/ptrace.h>
#include <asm/irq.h>
#include <asm/idle.h>
#include <asm/io_apic.h>
#include <asm/sync_bitops.h>
#include <asm/xen/pci.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/hypervisor.h>
#include <xen/xen.h>
#include <xen/hvm.h>
#include <xen/xen-ops.h>
#include <xen/events.h>
#include <xen/interface/xen.h>
#include <xen/interface/event_channel.h>
#include <xen/interface/hvm/hvm_op.h>
#include <xen/interface/hvm/params.h>
/*
* This lock protects updates to the following mapping and reference-count
* arrays. The lock does not need to be acquired to read the mapping tables.
*/
static DEFINE_MUTEX(irq_mapping_update_lock);
static LIST_HEAD(xen_irq_list_head);
/* IRQ <-> VIRQ mapping. */
static DEFINE_PER_CPU(int [NR_VIRQS], virq_to_irq) = {[0 ... NR_VIRQS-1] = -1};
/* IRQ <-> IPI mapping */
static DEFINE_PER_CPU(int [XEN_NR_IPIS], ipi_to_irq) = {[0 ... XEN_NR_IPIS-1] = -1};
/* Interrupt types. */
enum xen_irq_type {
IRQT_UNBOUND = 0,
IRQT_PIRQ,
IRQT_VIRQ,
IRQT_IPI,
IRQT_EVTCHN
};
/*
* Packed IRQ information:
* type - enum xen_irq_type
* event channel - irq->event channel mapping
* cpu - cpu this event channel is bound to
* index - type-specific information:
* PIRQ - vector, with MSB being "needs EIO", or physical IRQ of the HVM
* guest, or GSI (real passthrough IRQ) of the device.
* VIRQ - virq number
* IPI - IPI vector
* EVTCHN -
*/
struct irq_info {
struct list_head list;
int refcnt;
enum xen_irq_type type; /* type */
unsigned irq;
unsigned short evtchn; /* event channel */
unsigned short cpu; /* cpu bound */
union {
unsigned short virq;
enum ipi_vector ipi;
struct {
unsigned short pirq;
unsigned short gsi;
unsigned char vector;
unsigned char flags;
uint16_t domid;
} pirq;
} u;
};
#define PIRQ_NEEDS_EOI (1 << 0)
#define PIRQ_SHAREABLE (1 << 1)
static int *evtchn_to_irq;
static DEFINE_PER_CPU(unsigned long [NR_EVENT_CHANNELS/BITS_PER_LONG],
cpu_evtchn_mask);
/* Xen will never allocate port zero for any purpose. */
#define VALID_EVTCHN(chn) ((chn) != 0)
static struct irq_chip xen_dynamic_chip;
static struct irq_chip xen_percpu_chip;
static struct irq_chip xen_pirq_chip;
static void enable_dynirq(struct irq_data *data);
static void disable_dynirq(struct irq_data *data);
/* Get info for IRQ */
static struct irq_info *info_for_irq(unsigned irq)
{
return irq_get_handler_data(irq);
}
/* Constructors for packed IRQ information. */
static void xen_irq_info_common_init(struct irq_info *info,
unsigned irq,
enum xen_irq_type type,
unsigned short evtchn,
unsigned short cpu)
{
BUG_ON(info->type != IRQT_UNBOUND && info->type != type);
info->type = type;
info->irq = irq;
info->evtchn = evtchn;
info->cpu = cpu;
evtchn_to_irq[evtchn] = irq;
}
static void xen_irq_info_evtchn_init(unsigned irq,
unsigned short evtchn)
{
struct irq_info *info = info_for_irq(irq);
xen_irq_info_common_init(info, irq, IRQT_EVTCHN, evtchn, 0);
}
static void xen_irq_info_ipi_init(unsigned cpu,
unsigned irq,
unsigned short evtchn,
enum ipi_vector ipi)
{
struct irq_info *info = info_for_irq(irq);
xen_irq_info_common_init(info, irq, IRQT_IPI, evtchn, 0);
info->u.ipi = ipi;
per_cpu(ipi_to_irq, cpu)[ipi] = irq;
}
static void xen_irq_info_virq_init(unsigned cpu,
unsigned irq,
unsigned short evtchn,
unsigned short virq)
{
struct irq_info *info = info_for_irq(irq);
xen_irq_info_common_init(info, irq, IRQT_VIRQ, evtchn, 0);
info->u.virq = virq;
per_cpu(virq_to_irq, cpu)[virq] = irq;
}
static void xen_irq_info_pirq_init(unsigned irq,
unsigned short evtchn,
unsigned short pirq,
unsigned short gsi,
unsigned short vector,
uint16_t domid,
unsigned char flags)
{
struct irq_info *info = info_for_irq(irq);
xen_irq_info_common_init(info, irq, IRQT_PIRQ, evtchn, 0);
info->u.pirq.pirq = pirq;
info->u.pirq.gsi = gsi;
info->u.pirq.vector = vector;
info->u.pirq.domid = domid;
info->u.pirq.flags = flags;
}
/*
* Accessors for packed IRQ information.
*/
static unsigned int evtchn_from_irq(unsigned irq)
{
if (unlikely(WARN(irq < 0 || irq >= nr_irqs, "Invalid irq %d!\n", irq)))
return 0;
return info_for_irq(irq)->evtchn;
}
unsigned irq_from_evtchn(unsigned int evtchn)
{
return evtchn_to_irq[evtchn];
}
EXPORT_SYMBOL_GPL(irq_from_evtchn);
static enum ipi_vector ipi_from_irq(unsigned irq)
{
struct irq_info *info = info_for_irq(irq);
BUG_ON(info == NULL);
BUG_ON(info->type != IRQT_IPI);
return info->u.ipi;
}
static unsigned virq_from_irq(unsigned irq)
{
struct irq_info *info = info_for_irq(irq);
BUG_ON(info == NULL);
BUG_ON(info->type != IRQT_VIRQ);
return info->u.virq;
}
static unsigned pirq_from_irq(unsigned irq)
{
struct irq_info *info = info_for_irq(irq);
BUG_ON(info == NULL);
BUG_ON(info->type != IRQT_PIRQ);
return info->u.pirq.pirq;
}
static enum xen_irq_type type_from_irq(unsigned irq)
{
return info_for_irq(irq)->type;
}
static unsigned cpu_from_irq(unsigned irq)
{
return info_for_irq(irq)->cpu;
}
static unsigned int cpu_from_evtchn(unsigned int evtchn)
{
int irq = evtchn_to_irq[evtchn];
unsigned ret = 0;
if (irq != -1)
ret = cpu_from_irq(irq);
return ret;
}
static bool pirq_needs_eoi(unsigned irq)
{
struct irq_info *info = info_for_irq(irq);
BUG_ON(info->type != IRQT_PIRQ);
return info->u.pirq.flags & PIRQ_NEEDS_EOI;
}
static inline unsigned long active_evtchns(unsigned int cpu,
struct shared_info *sh,
unsigned int idx)
{
return sh->evtchn_pending[idx] &
per_cpu(cpu_evtchn_mask, cpu)[idx] &
~sh->evtchn_mask[idx];
}
static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
{
int irq = evtchn_to_irq[chn];
BUG_ON(irq == -1);
#ifdef CONFIG_SMP
cpumask_copy(irq_to_desc(irq)->irq_data.affinity, cpumask_of(cpu));
#endif
clear_bit(chn, per_cpu(cpu_evtchn_mask, cpu_from_irq(irq)));
set_bit(chn, per_cpu(cpu_evtchn_mask, cpu));
info_for_irq(irq)->cpu = cpu;
}
static void init_evtchn_cpu_bindings(void)
{
int i;
#ifdef CONFIG_SMP
struct irq_info *info;
/* By default all event channels notify CPU#0. */
list_for_each_entry(info, &xen_irq_list_head, list) {
struct irq_desc *desc = irq_to_desc(info->irq);
cpumask_copy(desc->irq_data.affinity, cpumask_of(0));
}
#endif
for_each_possible_cpu(i)
memset(per_cpu(cpu_evtchn_mask, i),
(i == 0) ? ~0 : 0, sizeof(*per_cpu(cpu_evtchn_mask, i)));
}
static inline void clear_evtchn(int port)
{
struct shared_info *s = HYPERVISOR_shared_info;
sync_clear_bit(port, &s->evtchn_pending[0]);
}
static inline void set_evtchn(int port)
{
struct shared_info *s = HYPERVISOR_shared_info;
sync_set_bit(port, &s->evtchn_pending[0]);
}
static inline int test_evtchn(int port)
{
struct shared_info *s = HYPERVISOR_shared_info;
return sync_test_bit(port, &s->evtchn_pending[0]);
}
/**
* notify_remote_via_irq - send event to remote end of event channel via irq
* @irq: irq of event channel to send event to
*
* Unlike notify_remote_via_evtchn(), this is safe to use across
* save/restore. Notifications on a broken connection are silently
* dropped.
*/
void notify_remote_via_irq(int irq)
{
int evtchn = evtchn_from_irq(irq);
if (VALID_EVTCHN(evtchn))
notify_remote_via_evtchn(evtchn);
}
EXPORT_SYMBOL_GPL(notify_remote_via_irq);
static void mask_evtchn(int port)
{
struct shared_info *s = HYPERVISOR_shared_info;
sync_set_bit(port, &s->evtchn_mask[0]);
}
static void unmask_evtchn(int port)
{
struct shared_info *s = HYPERVISOR_shared_info;
unsigned int cpu = get_cpu();
BUG_ON(!irqs_disabled());
/* Slow path (hypercall) if this is a non-local port. */
if (unlikely(cpu != cpu_from_evtchn(port))) {
struct evtchn_unmask unmask = { .port = port };
(void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
} else {
struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
sync_clear_bit(port, &s->evtchn_mask[0]);
/*
* The following is basically the equivalent of
* 'hw_resend_irq'. Just like a real IO-APIC we 'lose
* the interrupt edge' if the channel is masked.
*/
if (sync_test_bit(port, &s->evtchn_pending[0]) &&
!sync_test_and_set_bit(port / BITS_PER_LONG,
&vcpu_info->evtchn_pending_sel))
vcpu_info->evtchn_upcall_pending = 1;
}
put_cpu();
}
static void xen_irq_init(unsigned irq)
{
struct irq_info *info;
#ifdef CONFIG_SMP
struct irq_desc *desc = irq_to_desc(irq);
/* By default all event channels notify CPU#0. */
cpumask_copy(desc->irq_data.affinity, cpumask_of(0));
#endif
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (info == NULL)
panic("Unable to allocate metadata for IRQ%d\n", irq);
info->type = IRQT_UNBOUND;
info->refcnt = -1;
irq_set_handler_data(irq, info);
list_add_tail(&info->list, &xen_irq_list_head);
}
static int __must_check xen_allocate_irq_dynamic(void)
{
int first = 0;
int irq;
#ifdef CONFIG_X86_IO_APIC
/*
* For an HVM guest or domain 0 which see "real" (emulated or
* actual respectively) GSIs we allocate dynamic IRQs
* e.g. those corresponding to event channels or MSIs
* etc. from the range above those "real" GSIs to avoid
* collisions.
*/
if (xen_initial_domain() || xen_hvm_domain())
first = get_nr_irqs_gsi();
#endif
irq = irq_alloc_desc_from(first, -1);
if (irq >= 0)
xen_irq_init(irq);
return irq;
}
static int __must_check xen_allocate_irq_gsi(unsigned gsi)
{
int irq;
/*
* A PV guest has no concept of a GSI (since it has no ACPI
* nor access to/knowledge of the physical APICs). Therefore
* all IRQs are dynamically allocated from the entire IRQ
* space.
*/
if (xen_pv_domain() && !xen_initial_domain())
return xen_allocate_irq_dynamic();
/* Legacy IRQ descriptors are already allocated by the arch. */
if (gsi < NR_IRQS_LEGACY)
irq = gsi;
else
irq = irq_alloc_desc_at(gsi, -1);
xen_irq_init(irq);
return irq;
}
static void xen_free_irq(unsigned irq)
{
struct irq_info *info = irq_get_handler_data(irq);
list_del(&info->list);
irq_set_handler_data(irq, NULL);
WARN_ON(info->refcnt > 0);
kfree(info);
/* Legacy IRQ descriptors are managed by the arch. */
if (irq < NR_IRQS_LEGACY)
return;
irq_free_desc(irq);
}
static void pirq_query_unmask(int irq)
{
struct physdev_irq_status_query irq_status;
struct irq_info *info = info_for_irq(irq);
BUG_ON(info->type != IRQT_PIRQ);
irq_status.irq = pirq_from_irq(irq);
if (HYPERVISOR_physdev_op(PHYSDEVOP_irq_status_query, &irq_status))
irq_status.flags = 0;
info->u.pirq.flags &= ~PIRQ_NEEDS_EOI;
if (irq_status.flags & XENIRQSTAT_needs_eoi)
info->u.pirq.flags |= PIRQ_NEEDS_EOI;
}
static bool probing_irq(int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
return desc && desc->action == NULL;
}
static void eoi_pirq(struct irq_data *data)
{
int evtchn = evtchn_from_irq(data->irq);
struct physdev_eoi eoi = { .irq = pirq_from_irq(data->irq) };
int rc = 0;
irq_move_irq(data);
if (VALID_EVTCHN(evtchn))
clear_evtchn(evtchn);
if (pirq_needs_eoi(data->irq)) {
rc = HYPERVISOR_physdev_op(PHYSDEVOP_eoi, &eoi);
WARN_ON(rc);
}
}
static void mask_ack_pirq(struct irq_data *data)
{
disable_dynirq(data);
eoi_pirq(data);
}
static unsigned int __startup_pirq(unsigned int irq)
{
struct evtchn_bind_pirq bind_pirq;
struct irq_info *info = info_for_irq(irq);
int evtchn = evtchn_from_irq(irq);
int rc;
BUG_ON(info->type != IRQT_PIRQ);
if (VALID_EVTCHN(evtchn))
goto out;
bind_pirq.pirq = pirq_from_irq(irq);
/* NB. We are happy to share unless we are probing. */
bind_pirq.flags = info->u.pirq.flags & PIRQ_SHAREABLE ?
BIND_PIRQ__WILL_SHARE : 0;
rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_pirq, &bind_pirq);
if (rc != 0) {
if (!probing_irq(irq))
printk(KERN_INFO "Failed to obtain physical IRQ %d\n",
irq);
return 0;
}
evtchn = bind_pirq.port;
pirq_query_unmask(irq);
evtchn_to_irq[evtchn] = irq;
bind_evtchn_to_cpu(evtchn, 0);
info->evtchn = evtchn;
out:
unmask_evtchn(evtchn);
eoi_pirq(irq_get_irq_data(irq));
return 0;
}
static unsigned int startup_pirq(struct irq_data *data)
{
return __startup_pirq(data->irq);
}
static void shutdown_pirq(struct irq_data *data)
{
struct evtchn_close close;
unsigned int irq = data->irq;
struct irq_info *info = info_for_irq(irq);
int evtchn = evtchn_from_irq(irq);
BUG_ON(info->type != IRQT_PIRQ);
if (!VALID_EVTCHN(evtchn))
return;
mask_evtchn(evtchn);
close.port = evtchn;
if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
BUG();
bind_evtchn_to_cpu(evtchn, 0);
evtchn_to_irq[evtchn] = -1;
info->evtchn = 0;
}
static void enable_pirq(struct irq_data *data)
{
startup_pirq(data);
}
static void disable_pirq(struct irq_data *data)
{
disable_dynirq(data);
}
static int find_irq_by_gsi(unsigned gsi)
{
struct irq_info *info;
list_for_each_entry(info, &xen_irq_list_head, list) {
if (info->type != IRQT_PIRQ)
continue;
if (info->u.pirq.gsi == gsi)
return info->irq;
}
return -1;
}
/*
* Do not make any assumptions regarding the relationship between the
* IRQ number returned here and the Xen pirq argument.
*
* Note: We don't assign an event channel until the irq actually started
* up. Return an existing irq if we've already got one for the gsi.
*
* Shareable implies level triggered, not shareable implies edge
* triggered here.
*/
int xen_bind_pirq_gsi_to_irq(unsigned gsi,
unsigned pirq, int shareable, char *name)
{
int irq = -1;
struct physdev_irq irq_op;
mutex_lock(&irq_mapping_update_lock);
irq = find_irq_by_gsi(gsi);
if (irq != -1) {
printk(KERN_INFO "xen_map_pirq_gsi: returning irq %d for gsi %u\n",
irq, gsi);
goto out;
}
irq = xen_allocate_irq_gsi(gsi);
if (irq < 0)
goto out;
irq_op.irq = irq;
irq_op.vector = 0;
/* Only the privileged domain can do this. For non-priv, the pcifront
* driver provides a PCI bus that does the call to do exactly
* this in the priv domain. */
if (xen_initial_domain() &&
HYPERVISOR_physdev_op(PHYSDEVOP_alloc_irq_vector, &irq_op)) {
xen_free_irq(irq);
irq = -ENOSPC;
goto out;
}
xen_irq_info_pirq_init(irq, 0, pirq, gsi, irq_op.vector, DOMID_SELF,
shareable ? PIRQ_SHAREABLE : 0);
pirq_query_unmask(irq);
/* We try to use the handler with the appropriate semantic for the
* type of interrupt: if the interrupt is an edge triggered
* interrupt we use handle_edge_irq.
*
* On the other hand if the interrupt is level triggered we use
* handle_fasteoi_irq like the native code does for this kind of
* interrupts.
*
* Depending on the Xen version, pirq_needs_eoi might return true
* not only for level triggered interrupts but for edge triggered
* interrupts too. In any case Xen always honors the eoi mechanism,
* not injecting any more pirqs of the same kind if the first one
* hasn't received an eoi yet. Therefore using the fasteoi handler
* is the right choice either way.
*/
if (shareable)
irq_set_chip_and_handler_name(irq, &xen_pirq_chip,
handle_fasteoi_irq, name);
else
irq_set_chip_and_handler_name(irq, &xen_pirq_chip,
handle_edge_irq, name);
out:
mutex_unlock(&irq_mapping_update_lock);
return irq;
}
#ifdef CONFIG_PCI_MSI
int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc)
{
int rc;
struct physdev_get_free_pirq op_get_free_pirq;
op_get_free_pirq.type = MAP_PIRQ_TYPE_MSI;
rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_free_pirq, &op_get_free_pirq);
WARN_ONCE(rc == -ENOSYS,
"hypervisor does not support the PHYSDEVOP_get_free_pirq interface\n");
return rc ? -1 : op_get_free_pirq.pirq;
}
int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
int pirq, int vector, const char *name,
domid_t domid)
{
int irq, ret;
mutex_lock(&irq_mapping_update_lock);
irq = xen_allocate_irq_dynamic();
if (irq < 0)
goto out;
irq_set_chip_and_handler_name(irq, &xen_pirq_chip, handle_edge_irq,
name);
xen_irq_info_pirq_init(irq, 0, pirq, 0, vector, domid, 0);
ret = irq_set_msi_desc(irq, msidesc);
if (ret < 0)
goto error_irq;
out:
mutex_unlock(&irq_mapping_update_lock);
return irq;
error_irq:
mutex_unlock(&irq_mapping_update_lock);
xen_free_irq(irq);
return ret;
}
#endif
int xen_destroy_irq(int irq)
{
struct irq_desc *desc;
struct physdev_unmap_pirq unmap_irq;
struct irq_info *info = info_for_irq(irq);
int rc = -ENOENT;
mutex_lock(&irq_mapping_update_lock);
desc = irq_to_desc(irq);
if (!desc)
goto out;
if (xen_initial_domain()) {
unmap_irq.pirq = info->u.pirq.pirq;
unmap_irq.domid = info->u.pirq.domid;
rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
/* If another domain quits without making the pci_disable_msix
* call, the Xen hypervisor takes care of freeing the PIRQs
* (free_domain_pirqs).
*/
if ((rc == -ESRCH && info->u.pirq.domid != DOMID_SELF))
printk(KERN_INFO "domain %d does not have %d anymore\n",
info->u.pirq.domid, info->u.pirq.pirq);
else if (rc) {
printk(KERN_WARNING "unmap irq failed %d\n", rc);
goto out;
}
}
xen_free_irq(irq);
out:
mutex_unlock(&irq_mapping_update_lock);
return rc;
}
int xen_irq_from_pirq(unsigned pirq)
{
int irq;
struct irq_info *info;
mutex_lock(&irq_mapping_update_lock);
list_for_each_entry(info, &xen_irq_list_head, list) {
if (info->type != IRQT_PIRQ)
continue;
irq = info->irq;
if (info->u.pirq.pirq == pirq)
goto out;
}
irq = -1;
out:
mutex_unlock(&irq_mapping_update_lock);
return irq;
}
int xen_pirq_from_irq(unsigned irq)
{
return pirq_from_irq(irq);
}
EXPORT_SYMBOL_GPL(xen_pirq_from_irq);
int bind_evtchn_to_irq(unsigned int evtchn)
{
int irq;
mutex_lock(&irq_mapping_update_lock);
irq = evtchn_to_irq[evtchn];
if (irq == -1) {
irq = xen_allocate_irq_dynamic();
if (irq == -1)
goto out;
irq_set_chip_and_handler_name(irq, &xen_dynamic_chip,
handle_edge_irq, "event");
xen_irq_info_evtchn_init(irq, evtchn);
}
out:
mutex_unlock(&irq_mapping_update_lock);
return irq;
}
EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
{
struct evtchn_bind_ipi bind_ipi;
int evtchn, irq;
mutex_lock(&irq_mapping_update_lock);
irq = per_cpu(ipi_to_irq, cpu)[ipi];
if (irq == -1) {
irq = xen_allocate_irq_dynamic();
if (irq < 0)
goto out;
irq_set_chip_and_handler_name(irq, &xen_percpu_chip,
handle_percpu_irq, "ipi");
bind_ipi.vcpu = cpu;
if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
&bind_ipi) != 0)
BUG();
evtchn = bind_ipi.port;
xen_irq_info_ipi_init(cpu, irq, evtchn, ipi);
bind_evtchn_to_cpu(evtchn, cpu);
}
out:
mutex_unlock(&irq_mapping_update_lock);
return irq;
}
static int bind_interdomain_evtchn_to_irq(unsigned int remote_domain,
unsigned int remote_port)
{
struct evtchn_bind_interdomain bind_interdomain;
int err;
bind_interdomain.remote_dom = remote_domain;
bind_interdomain.remote_port = remote_port;
err = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
&bind_interdomain);
return err ? : bind_evtchn_to_irq(bind_interdomain.local_port);
}
static int find_virq(unsigned int virq, unsigned int cpu)
{
struct evtchn_status status;
int port, rc = -ENOENT;
memset(&status, 0, sizeof(status));
for (port = 0; port <= NR_EVENT_CHANNELS; port++) {
status.dom = DOMID_SELF;
status.port = port;
rc = HYPERVISOR_event_channel_op(EVTCHNOP_status, &status);
if (rc < 0)
continue;
if (status.status != EVTCHNSTAT_virq)
continue;
if (status.u.virq == virq && status.vcpu == cpu) {
rc = port;
break;
}
}
return rc;
}
int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
{
struct evtchn_bind_virq bind_virq;
int evtchn, irq, ret;
mutex_lock(&irq_mapping_update_lock);
irq = per_cpu(virq_to_irq, cpu)[virq];
if (irq == -1) {
irq = xen_allocate_irq_dynamic();
if (irq == -1)
goto out;
irq_set_chip_and_handler_name(irq, &xen_percpu_chip,
handle_percpu_irq, "virq");
bind_virq.virq = virq;
bind_virq.vcpu = cpu;
ret = HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
&bind_virq);
if (ret == 0)
evtchn = bind_virq.port;
else {
if (ret == -EEXIST)
ret = find_virq(virq, cpu);
BUG_ON(ret < 0);
evtchn = ret;
}
xen_irq_info_virq_init(cpu, irq, evtchn, virq);
bind_evtchn_to_cpu(evtchn, cpu);
}
out:
mutex_unlock(&irq_mapping_update_lock);
return irq;
}
static void unbind_from_irq(unsigned int irq)
{
struct evtchn_close close;
int evtchn = evtchn_from_irq(irq);
struct irq_info *info = irq_get_handler_data(irq);
mutex_lock(&irq_mapping_update_lock);
if (info->refcnt > 0) {
info->refcnt--;
if (info->refcnt != 0)
goto done;
}
if (VALID_EVTCHN(evtchn)) {
close.port = evtchn;
if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
BUG();
switch (type_from_irq(irq)) {
case IRQT_VIRQ:
per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))
[virq_from_irq(irq)] = -1;
break;
case IRQT_IPI:
per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn))
[ipi_from_irq(irq)] = -1;
break;
default:
break;
}
/* Closed ports are implicitly re-bound to VCPU0. */
bind_evtchn_to_cpu(evtchn, 0);
evtchn_to_irq[evtchn] = -1;
}
BUG_ON(info_for_irq(irq)->type == IRQT_UNBOUND);
xen_free_irq(irq);
done:
mutex_unlock(&irq_mapping_update_lock);
}
int bind_evtchn_to_irqhandler(unsigned int evtchn,
irq_handler_t handler,
unsigned long irqflags,
const char *devname, void *dev_id)
{
int irq, retval;
irq = bind_evtchn_to_irq(evtchn);
if (irq < 0)
return irq;
retval = request_irq(irq, handler, irqflags, devname, dev_id);
if (retval != 0) {
unbind_from_irq(irq);