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linux-zen-server/drivers/xen/events/events_base.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* 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
*/
#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
#include <linux/linkage.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/moduleparam.h>
#include <linux/string.h>
#include <linux/memblock.h>
#include <linux/slab.h>
#include <linux/irqnr.h>
#include <linux/pci.h>
#include <linux/spinlock.h>
#include <linux/cpuhotplug.h>
#include <linux/atomic.h>
#include <linux/ktime.h>
#ifdef CONFIG_X86
#include <asm/desc.h>
#include <asm/ptrace.h>
#include <asm/idtentry.h>
#include <asm/irq.h>
#include <asm/io_apic.h>
#include <asm/i8259.h>
#include <asm/xen/cpuid.h>
#include <asm/xen/pci.h>
#endif
#include <asm/sync_bitops.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/hypervisor.h>
#include <xen/page.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>
#include <xen/interface/physdev.h>
#include <xen/interface/sched.h>
#include <xen/interface/vcpu.h>
#include <xen/xenbus.h>
#include <asm/hw_irq.h>
#include "events_internal.h"
#undef MODULE_PARAM_PREFIX
#define MODULE_PARAM_PREFIX "xen."
/* 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;
struct list_head eoi_list;
short refcnt;
u8 spurious_cnt;
u8 is_accounted;
short type; /* type: IRQT_* */
u8 mask_reason; /* Why is event channel masked */
#define EVT_MASK_REASON_EXPLICIT 0x01
#define EVT_MASK_REASON_TEMPORARY 0x02
#define EVT_MASK_REASON_EOI_PENDING 0x04
u8 is_active; /* Is event just being handled? */
unsigned irq;
evtchn_port_t evtchn; /* event channel */
unsigned short cpu; /* cpu bound */
unsigned short eoi_cpu; /* EOI must happen on this cpu-1 */
unsigned int irq_epoch; /* If eoi_cpu valid: irq_epoch of event */
u64 eoi_time; /* Time in jiffies when to EOI. */
raw_spinlock_t lock;
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;
struct xenbus_device *interdomain;
} u;
};
#define PIRQ_NEEDS_EOI (1 << 0)
#define PIRQ_SHAREABLE (1 << 1)
#define PIRQ_MSI_GROUP (1 << 2)
static uint __read_mostly event_loop_timeout = 2;
module_param(event_loop_timeout, uint, 0644);
static uint __read_mostly event_eoi_delay = 10;
module_param(event_eoi_delay, uint, 0644);
const struct evtchn_ops *evtchn_ops;
/*
* 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);
/*
* Lock protecting event handling loop against removing event channels.
* Adding of event channels is no issue as the associated IRQ becomes active
* only after everything is setup (before request_[threaded_]irq() the handler
* can't be entered for an event, as the event channel will be unmasked only
* then).
*/
static DEFINE_RWLOCK(evtchn_rwlock);
/*
* Lock hierarchy:
*
* irq_mapping_update_lock
* evtchn_rwlock
* IRQ-desc lock
* percpu eoi_list_lock
* irq_info->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};
/* Event channel distribution data */
static atomic_t channels_on_cpu[NR_CPUS];
static int **evtchn_to_irq;
#ifdef CONFIG_X86
static unsigned long *pirq_eoi_map;
#endif
static bool (*pirq_needs_eoi)(unsigned irq);
#define EVTCHN_ROW(e) (e / (PAGE_SIZE/sizeof(**evtchn_to_irq)))
#define EVTCHN_COL(e) (e % (PAGE_SIZE/sizeof(**evtchn_to_irq)))
#define EVTCHN_PER_ROW (PAGE_SIZE / sizeof(**evtchn_to_irq))
/* Xen will never allocate port zero for any purpose. */
#define VALID_EVTCHN(chn) ((chn) != 0)
static struct irq_info *legacy_info_ptrs[NR_IRQS_LEGACY];
static struct irq_chip xen_dynamic_chip;
static struct irq_chip xen_lateeoi_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);
static DEFINE_PER_CPU(unsigned int, irq_epoch);
static void clear_evtchn_to_irq_row(int *evtchn_row)
{
unsigned col;
for (col = 0; col < EVTCHN_PER_ROW; col++)
WRITE_ONCE(evtchn_row[col], -1);
}
static void clear_evtchn_to_irq_all(void)
{
unsigned row;
for (row = 0; row < EVTCHN_ROW(xen_evtchn_max_channels()); row++) {
if (evtchn_to_irq[row] == NULL)
continue;
clear_evtchn_to_irq_row(evtchn_to_irq[row]);
}
}
static int set_evtchn_to_irq(evtchn_port_t evtchn, unsigned int irq)
{
unsigned row;
unsigned col;
int *evtchn_row;
if (evtchn >= xen_evtchn_max_channels())
return -EINVAL;
row = EVTCHN_ROW(evtchn);
col = EVTCHN_COL(evtchn);
if (evtchn_to_irq[row] == NULL) {
/* Unallocated irq entries return -1 anyway */
if (irq == -1)
return 0;
evtchn_row = (int *) __get_free_pages(GFP_KERNEL, 0);
if (evtchn_row == NULL)
return -ENOMEM;
clear_evtchn_to_irq_row(evtchn_row);
/*
* We've prepared an empty row for the mapping. If a different
* thread was faster inserting it, we can drop ours.
*/
if (cmpxchg(&evtchn_to_irq[row], NULL, evtchn_row) != NULL)
free_page((unsigned long) evtchn_row);
}
WRITE_ONCE(evtchn_to_irq[row][col], irq);
return 0;
}
int get_evtchn_to_irq(evtchn_port_t evtchn)
{
if (evtchn >= xen_evtchn_max_channels())
return -1;
if (evtchn_to_irq[EVTCHN_ROW(evtchn)] == NULL)
return -1;
return READ_ONCE(evtchn_to_irq[EVTCHN_ROW(evtchn)][EVTCHN_COL(evtchn)]);
}
/* Get info for IRQ */
static struct irq_info *info_for_irq(unsigned irq)
{
if (irq < nr_legacy_irqs())
return legacy_info_ptrs[irq];
else
return irq_get_chip_data(irq);
}
static void set_info_for_irq(unsigned int irq, struct irq_info *info)
{
if (irq < nr_legacy_irqs())
legacy_info_ptrs[irq] = info;
else
irq_set_chip_data(irq, info);
}
/* Per CPU channel accounting */
static void channels_on_cpu_dec(struct irq_info *info)
{
if (!info->is_accounted)
return;
info->is_accounted = 0;
if (WARN_ON_ONCE(info->cpu >= nr_cpu_ids))
return;
WARN_ON_ONCE(!atomic_add_unless(&channels_on_cpu[info->cpu], -1 , 0));
}
static void channels_on_cpu_inc(struct irq_info *info)
{
if (WARN_ON_ONCE(info->cpu >= nr_cpu_ids))
return;
if (WARN_ON_ONCE(!atomic_add_unless(&channels_on_cpu[info->cpu], 1,
INT_MAX)))
return;
info->is_accounted = 1;
}
/* Constructors for packed IRQ information. */
static int xen_irq_info_common_setup(struct irq_info *info,
unsigned irq,
enum xen_irq_type type,
evtchn_port_t evtchn,
unsigned short cpu)
{
int ret;
BUG_ON(info->type != IRQT_UNBOUND && info->type != type);
info->type = type;
info->irq = irq;
info->evtchn = evtchn;
info->cpu = cpu;
info->mask_reason = EVT_MASK_REASON_EXPLICIT;
raw_spin_lock_init(&info->lock);
ret = set_evtchn_to_irq(evtchn, irq);
if (ret < 0)
return ret;
irq_clear_status_flags(irq, IRQ_NOREQUEST|IRQ_NOAUTOEN);
return xen_evtchn_port_setup(evtchn);
}
static int xen_irq_info_evtchn_setup(unsigned irq,
evtchn_port_t evtchn,
struct xenbus_device *dev)
{
struct irq_info *info = info_for_irq(irq);
int ret;
ret = xen_irq_info_common_setup(info, irq, IRQT_EVTCHN, evtchn, 0);
info->u.interdomain = dev;
if (dev)
atomic_inc(&dev->event_channels);
return ret;
}
static int xen_irq_info_ipi_setup(unsigned cpu,
unsigned irq,
evtchn_port_t evtchn,
enum ipi_vector ipi)
{
struct irq_info *info = info_for_irq(irq);
info->u.ipi = ipi;
per_cpu(ipi_to_irq, cpu)[ipi] = irq;
return xen_irq_info_common_setup(info, irq, IRQT_IPI, evtchn, 0);
}
static int xen_irq_info_virq_setup(unsigned cpu,
unsigned irq,
evtchn_port_t evtchn,
unsigned virq)
{
struct irq_info *info = info_for_irq(irq);
info->u.virq = virq;
per_cpu(virq_to_irq, cpu)[virq] = irq;
return xen_irq_info_common_setup(info, irq, IRQT_VIRQ, evtchn, 0);
}
static int xen_irq_info_pirq_setup(unsigned irq,
evtchn_port_t evtchn,
unsigned pirq,
unsigned gsi,
uint16_t domid,
unsigned char flags)
{
struct irq_info *info = info_for_irq(irq);
info->u.pirq.pirq = pirq;
info->u.pirq.gsi = gsi;
info->u.pirq.domid = domid;
info->u.pirq.flags = flags;
return xen_irq_info_common_setup(info, irq, IRQT_PIRQ, evtchn, 0);
}
static void xen_irq_info_cleanup(struct irq_info *info)
{
set_evtchn_to_irq(info->evtchn, -1);
xen_evtchn_port_remove(info->evtchn, info->cpu);
info->evtchn = 0;
channels_on_cpu_dec(info);
}
/*
* Accessors for packed IRQ information.
*/
evtchn_port_t evtchn_from_irq(unsigned irq)
{
const struct irq_info *info = NULL;
if (likely(irq < nr_irqs))
info = info_for_irq(irq);
if (!info)
return 0;
return info->evtchn;
}
unsigned int irq_from_evtchn(evtchn_port_t evtchn)
{
return get_evtchn_to_irq(evtchn);
}
EXPORT_SYMBOL_GPL(irq_from_evtchn);
int irq_from_virq(unsigned int cpu, unsigned int virq)
{
return per_cpu(virq_to_irq, cpu)[virq];
}
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;
}
unsigned int cpu_from_evtchn(evtchn_port_t evtchn)
{
int irq = get_evtchn_to_irq(evtchn);
unsigned ret = 0;
if (irq != -1)
ret = cpu_from_irq(irq);
return ret;
}
static void do_mask(struct irq_info *info, u8 reason)
{
unsigned long flags;
raw_spin_lock_irqsave(&info->lock, flags);
if (!info->mask_reason)
mask_evtchn(info->evtchn);
info->mask_reason |= reason;
raw_spin_unlock_irqrestore(&info->lock, flags);
}
static void do_unmask(struct irq_info *info, u8 reason)
{
unsigned long flags;
raw_spin_lock_irqsave(&info->lock, flags);
info->mask_reason &= ~reason;
if (!info->mask_reason)
unmask_evtchn(info->evtchn);
raw_spin_unlock_irqrestore(&info->lock, flags);
}
#ifdef CONFIG_X86
static bool pirq_check_eoi_map(unsigned irq)
{
return test_bit(pirq_from_irq(irq), pirq_eoi_map);
}
#endif
static bool pirq_needs_eoi_flag(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 void bind_evtchn_to_cpu(evtchn_port_t evtchn, unsigned int cpu,
bool force_affinity)
{
int irq = get_evtchn_to_irq(evtchn);
struct irq_info *info = info_for_irq(irq);
BUG_ON(irq == -1);
if (IS_ENABLED(CONFIG_SMP) && force_affinity) {
struct irq_data *data = irq_get_irq_data(irq);
irq_data_update_affinity(data, cpumask_of(cpu));
irq_data_update_effective_affinity(data, cpumask_of(cpu));
}
xen_evtchn_port_bind_to_cpu(evtchn, cpu, info->cpu);
channels_on_cpu_dec(info);
info->cpu = cpu;
channels_on_cpu_inc(info);
}
/**
* 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)
{
evtchn_port_t evtchn = evtchn_from_irq(irq);
if (VALID_EVTCHN(evtchn))
notify_remote_via_evtchn(evtchn);
}
EXPORT_SYMBOL_GPL(notify_remote_via_irq);
struct lateeoi_work {
struct delayed_work delayed;
spinlock_t eoi_list_lock;
struct list_head eoi_list;
};
static DEFINE_PER_CPU(struct lateeoi_work, lateeoi);
static void lateeoi_list_del(struct irq_info *info)
{
struct lateeoi_work *eoi = &per_cpu(lateeoi, info->eoi_cpu);
unsigned long flags;
spin_lock_irqsave(&eoi->eoi_list_lock, flags);
list_del_init(&info->eoi_list);
spin_unlock_irqrestore(&eoi->eoi_list_lock, flags);
}
static void lateeoi_list_add(struct irq_info *info)
{
struct lateeoi_work *eoi = &per_cpu(lateeoi, info->eoi_cpu);
struct irq_info *elem;
u64 now = get_jiffies_64();
unsigned long delay;
unsigned long flags;
if (now < info->eoi_time)
delay = info->eoi_time - now;
else
delay = 1;
spin_lock_irqsave(&eoi->eoi_list_lock, flags);
if (list_empty(&eoi->eoi_list)) {
list_add(&info->eoi_list, &eoi->eoi_list);
mod_delayed_work_on(info->eoi_cpu, system_wq,
&eoi->delayed, delay);
} else {
list_for_each_entry_reverse(elem, &eoi->eoi_list, eoi_list) {
if (elem->eoi_time <= info->eoi_time)
break;
}
list_add(&info->eoi_list, &elem->eoi_list);
}
spin_unlock_irqrestore(&eoi->eoi_list_lock, flags);
}
static void xen_irq_lateeoi_locked(struct irq_info *info, bool spurious)
{
evtchn_port_t evtchn;
unsigned int cpu;
unsigned int delay = 0;
evtchn = info->evtchn;
if (!VALID_EVTCHN(evtchn) || !list_empty(&info->eoi_list))
return;
if (spurious) {
struct xenbus_device *dev = info->u.interdomain;
unsigned int threshold = 1;
if (dev && dev->spurious_threshold)
threshold = dev->spurious_threshold;
if ((1 << info->spurious_cnt) < (HZ << 2)) {
if (info->spurious_cnt != 0xFF)
info->spurious_cnt++;
}
if (info->spurious_cnt > threshold) {
delay = 1 << (info->spurious_cnt - 1 - threshold);
if (delay > HZ)
delay = HZ;
if (!info->eoi_time)
info->eoi_cpu = smp_processor_id();
info->eoi_time = get_jiffies_64() + delay;
if (dev)
atomic_add(delay, &dev->jiffies_eoi_delayed);
}
if (dev)
atomic_inc(&dev->spurious_events);
} else {
info->spurious_cnt = 0;
}
cpu = info->eoi_cpu;
if (info->eoi_time &&
(info->irq_epoch == per_cpu(irq_epoch, cpu) || delay)) {
lateeoi_list_add(info);
return;
}
info->eoi_time = 0;
/* is_active hasn't been reset yet, do it now. */
smp_store_release(&info->is_active, 0);
do_unmask(info, EVT_MASK_REASON_EOI_PENDING);
}
static void xen_irq_lateeoi_worker(struct work_struct *work)
{
struct lateeoi_work *eoi;
struct irq_info *info;
u64 now = get_jiffies_64();
unsigned long flags;
eoi = container_of(to_delayed_work(work), struct lateeoi_work, delayed);
read_lock_irqsave(&evtchn_rwlock, flags);
while (true) {
spin_lock(&eoi->eoi_list_lock);
info = list_first_entry_or_null(&eoi->eoi_list, struct irq_info,
eoi_list);
if (info == NULL || now < info->eoi_time) {
spin_unlock(&eoi->eoi_list_lock);
break;
}
list_del_init(&info->eoi_list);
spin_unlock(&eoi->eoi_list_lock);
info->eoi_time = 0;
xen_irq_lateeoi_locked(info, false);
}
if (info)
mod_delayed_work_on(info->eoi_cpu, system_wq,
&eoi->delayed, info->eoi_time - now);
read_unlock_irqrestore(&evtchn_rwlock, flags);
}
static void xen_cpu_init_eoi(unsigned int cpu)
{
struct lateeoi_work *eoi = &per_cpu(lateeoi, cpu);
INIT_DELAYED_WORK(&eoi->delayed, xen_irq_lateeoi_worker);
spin_lock_init(&eoi->eoi_list_lock);
INIT_LIST_HEAD(&eoi->eoi_list);
}
void xen_irq_lateeoi(unsigned int irq, unsigned int eoi_flags)
{
struct irq_info *info;
unsigned long flags;
read_lock_irqsave(&evtchn_rwlock, flags);
info = info_for_irq(irq);
if (info)
xen_irq_lateeoi_locked(info, eoi_flags & XEN_EOI_FLAG_SPURIOUS);
read_unlock_irqrestore(&evtchn_rwlock, flags);
}
EXPORT_SYMBOL_GPL(xen_irq_lateeoi);
static void xen_irq_init(unsigned irq)
{
struct irq_info *info;
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;
set_info_for_irq(irq, info);
/*
* Interrupt affinity setting can be immediate. No point
* in delaying it until an interrupt is handled.
*/
irq_set_status_flags(irq, IRQ_MOVE_PCNTXT);
INIT_LIST_HEAD(&info->eoi_list);
list_add_tail(&info->list, &xen_irq_list_head);
}
static int __must_check xen_allocate_irqs_dynamic(int nvec)
{
int i, irq = irq_alloc_descs(-1, 0, nvec, -1);
if (irq >= 0) {
for (i = 0; i < nvec; i++)
xen_irq_init(irq + i);
}
return irq;
}
static inline int __must_check xen_allocate_irq_dynamic(void)
{
return xen_allocate_irqs_dynamic(1);
}
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_legacy_irqs())
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 = info_for_irq(irq);
unsigned long flags;
if (WARN_ON(!info))
return;
write_lock_irqsave(&evtchn_rwlock, flags);
if (!list_empty(&info->eoi_list))
lateeoi_list_del(info);
list_del(&info->list);
set_info_for_irq(irq, NULL);
WARN_ON(info->refcnt > 0);
write_unlock_irqrestore(&evtchn_rwlock, flags);
kfree(info);
/* Legacy IRQ descriptors are managed by the arch. */
if (irq < nr_legacy_irqs())
return;
irq_free_desc(irq);
}
static void xen_evtchn_close(evtchn_port_t port)
{
struct evtchn_close close;
close.port = port;
if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
BUG();
}
/* Not called for lateeoi events. */
static void event_handler_exit(struct irq_info *info)
{
smp_store_release(&info->is_active, 0);
clear_evtchn(info->evtchn);
}
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 void eoi_pirq(struct irq_data *data)
{
struct irq_info *info = info_for_irq(data->irq);
evtchn_port_t evtchn = info ? info->evtchn : 0;
struct physdev_eoi eoi = { .irq = pirq_from_irq(data->irq) };
int rc = 0;
if (!VALID_EVTCHN(evtchn))
return;
event_handler_exit(info);
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);
evtchn_port_t 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) {
pr_warn("Failed to obtain physical IRQ %d\n", irq);
return 0;
}
evtchn = bind_pirq.port;
pirq_query_unmask(irq);
rc = set_evtchn_to_irq(evtchn, irq);
if (rc)
goto err;
info->evtchn = evtchn;
bind_evtchn_to_cpu(evtchn, 0, false);
rc = xen_evtchn_port_setup(evtchn);
if (rc)
goto err;
out:
do_unmask(info, EVT_MASK_REASON_EXPLICIT);
eoi_pirq(irq_get_irq_data(irq));
return 0;
err:
pr_err("irq%d: Failed to set port to irq mapping (%d)\n", irq, rc);
xen_evtchn_close(evtchn);
return 0;
}
static unsigned int startup_pirq(struct irq_data *data)
{
return __startup_pirq(data->irq);
}
static void shutdown_pirq(struct irq_data *data)
{
unsigned int irq = data->irq;
struct irq_info *info = info_for_irq(irq);
evtchn_port_t evtchn = evtchn_from_irq(irq);
BUG_ON(info->type != IRQT_PIRQ);
if (!VALID_EVTCHN(evtchn))
return;
do_mask(info, EVT_MASK_REASON_EXPLICIT);
xen_evtchn_close(evtchn);
xen_irq_info_cleanup(info);
}
static void enable_pirq(struct irq_data *data)
{
enable_dynirq(data);
}
static void disable_pirq(struct irq_data *data)
{
disable_dynirq(data);
}
int xen_irq_from_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;
}
EXPORT_SYMBOL_GPL(xen_irq_from_gsi);
static void __unbind_from_irq(unsigned int irq)
{
evtchn_port_t evtchn = evtchn_from_irq(irq);
struct irq_info *info = info_for_irq(irq);
if (info->refcnt > 0) {
info->refcnt--;
if (info->refcnt != 0)
return;
}
if (VALID_EVTCHN(evtchn)) {
unsigned int cpu = cpu_from_irq(irq);
struct xenbus_device *dev;
xen_evtchn_close(evtchn);
switch (type_from_irq(irq)) {
case IRQT_VIRQ:
per_cpu(virq_to_irq, cpu)[virq_from_irq(irq)] = -1;
break;
case IRQT_IPI:
per_cpu(ipi_to_irq, cpu)[ipi_from_irq(irq)] = -1;
break;
case IRQT_EVTCHN:
dev = info->u.interdomain;
if (dev)
atomic_dec(&dev->event_channels);
break;
default:
break;
}
xen_irq_info_cleanup(info);
}
xen_free_irq(irq);
}
/*
* 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;
struct physdev_irq irq_op;
int ret;
mutex_lock(&irq_mapping_update_lock);
irq = xen_irq_from_gsi(gsi);
if (irq != -1) {
pr_info("%s: returning irq %d for gsi %u\n",
__func__, 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;
}
ret = xen_irq_info_pirq_setup(irq, 0, pirq, gsi, DOMID_SELF,
shareable ? PIRQ_SHAREABLE : 0);
if (ret < 0) {
__unbind_from_irq(irq);
irq = ret;
goto out;
}
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 nvec, const char *name, domid_t domid)
{
int i, irq, ret;
mutex_lock(&irq_mapping_update_lock);
irq = xen_allocate_irqs_dynamic(nvec);
if (irq < 0)
goto out;
for (i = 0; i < nvec; i++) {
irq_set_chip_and_handler_name(irq + i, &xen_pirq_chip, handle_edge_irq, name);
ret = xen_irq_info_pirq_setup(irq + i, 0, pirq + i, 0, domid,
i == 0 ? 0 : PIRQ_MSI_GROUP);
if (ret < 0)
goto error_irq;
}
ret = irq_set_msi_desc(irq, msidesc);
if (ret < 0)
goto error_irq;
out:
mutex_unlock(&irq_mapping_update_lock);
return irq;
error_irq:
while (nvec--)
__unbind_from_irq(irq + nvec);
mutex_unlock(&irq_mapping_update_lock);
return ret;
}
#endif
int xen_destroy_irq(int irq)
{
struct physdev_unmap_pirq unmap_irq;
struct irq_info *info = info_for_irq(irq);
int rc = -ENOENT;
mutex_lock(&irq_mapping_update_lock);
/*
* If trying to remove a vector in a MSI group different
* than the first one skip the PIRQ unmap unless this vector
* is the first one in the group.
*/
if (xen_initial_domain() && !(info->u.pirq.flags & PIRQ_MSI_GROUP)) {
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))
pr_info("domain %d does not have %d anymore\n",
info->u.pirq.domid, info->u.pirq.pirq);
else if (rc) {
pr_warn("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);
static int bind_evtchn_to_irq_chip(evtchn_port_t evtchn, struct irq_chip *chip,
struct xenbus_device *dev)
{
int irq;
int ret;
if (evtchn >= xen_evtchn_max_channels())
return -ENOMEM;
mutex_lock(&irq_mapping_update_lock);
irq = get_evtchn_to_irq(evtchn);
if (irq == -1) {
irq = xen_allocate_irq_dynamic();
if (irq < 0)
goto out;
irq_set_chip_and_handler_name(irq, chip,
handle_edge_irq, "event");
ret = xen_irq_info_evtchn_setup(irq, evtchn, dev);
if (ret < 0) {
__unbind_from_irq(irq);
irq = ret;
goto out;
}
/*
* New interdomain events are initially bound to vCPU0 This
* is required to setup the event channel in the first
* place and also important for UP guests because the
* affinity setting is not invoked on them so nothing would
* bind the channel.
*/
bind_evtchn_to_cpu(evtchn, 0, false);
} else {
struct irq_info *info = info_for_irq(irq);
WARN_ON(info == NULL || info->type != IRQT_EVTCHN);
}
out:
mutex_unlock(&irq_mapping_update_lock);
return irq;
}
int bind_evtchn_to_irq(evtchn_port_t evtchn)
{
return bind_evtchn_to_irq_chip(evtchn, &xen_dynamic_chip, NULL);
}
EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
int bind_evtchn_to_irq_lateeoi(evtchn_port_t evtchn)
{
return bind_evtchn_to_irq_chip(evtchn, &xen_lateeoi_chip, NULL);
}
EXPORT_SYMBOL_GPL(bind_evtchn_to_irq_lateeoi);
static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
{
struct evtchn_bind_ipi bind_ipi;
evtchn_port_t evtchn;
int ret, 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 = xen_vcpu_nr(cpu);
if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
&bind_ipi) != 0)
BUG();
evtchn = bind_ipi.port;
ret = xen_irq_info_ipi_setup(cpu, irq, evtchn, ipi);
if (ret < 0) {
__unbind_from_irq(irq);
irq = ret;
goto out;
}
/*
* Force the affinity mask to the target CPU so proc shows
* the correct target.
*/
bind_evtchn_to_cpu(evtchn, cpu, true);
} else {
struct irq_info *info = info_for_irq(irq);
WARN_ON(info == NULL || info->type != IRQT_IPI);
}
out:
mutex_unlock(&irq_mapping_update_lock);
return irq;
}
static int bind_interdomain_evtchn_to_irq_chip(struct xenbus_device *dev,
evtchn_port_t remote_port,
struct irq_chip *chip)
{
struct evtchn_bind_interdomain bind_interdomain;
int err;
bind_interdomain.remote_dom = dev->otherend_id;
bind_interdomain.remote_port = remote_port;
err = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
&bind_interdomain);
return err ? : bind_evtchn_to_irq_chip(bind_interdomain.local_port,
chip, dev);
}
int bind_interdomain_evtchn_to_irq_lateeoi(struct xenbus_device *dev,
evtchn_port_t remote_port)
{
return bind_interdomain_evtchn_to_irq_chip(dev, remote_port,
&xen_lateeoi_chip);
}
EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irq_lateeoi);
static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn)
{
struct evtchn_status status;
evtchn_port_t port;
int rc = -ENOENT;
memset(&status, 0, sizeof(status));
for (port = 0; port < xen_evtchn_max_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 == xen_vcpu_nr(cpu)) {
*evtchn = port;
break;
}
}
return rc;
}
/**
* xen_evtchn_nr_channels - number of usable event channel ports
*
* This may be less than the maximum supported by the current
* hypervisor ABI. Use xen_evtchn_max_channels() for the maximum
* supported.
*/
unsigned xen_evtchn_nr_channels(void)
{
return evtchn_ops->nr_channels();
}
EXPORT_SYMBOL_GPL(xen_evtchn_nr_channels);
int bind_virq_to_irq(unsigned int virq, unsigned int cpu, bool percpu)
{
struct evtchn_bind_virq bind_virq;
evtchn_port_t evtchn = 0;
int 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 < 0)
goto out;
if (percpu)
irq_set_chip_and_handler_name(irq, &xen_percpu_chip,
handle_percpu_irq, "virq");
else
irq_set_chip_and_handler_name(irq, &xen_dynamic_chip,
handle_edge_irq, "virq");
bind_virq.virq = virq;
bind_virq.vcpu = xen_vcpu_nr(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, &evtchn);
BUG_ON(ret < 0);
}
ret = xen_irq_info_virq_setup(cpu, irq, evtchn, virq);
if (ret < 0) {
__unbind_from_irq(irq);
irq = ret;
goto out;
}
/*
* Force the affinity mask for percpu interrupts so proc
* shows the correct target.
*/
bind_evtchn_to_cpu(evtchn, cpu, percpu);
} else {
struct irq_info *info = info_for_irq(irq);
WARN_ON(info == NULL || info->type != IRQT_VIRQ);
}
out:
mutex_unlock(&irq_mapping_update_lock);
return irq;
}
static void unbind_from_irq(unsigned int irq)
{
mutex_lock(&irq_mapping_update_lock);
__unbind_from_irq(irq);
mutex_unlock(&irq_mapping_update_lock);
}
static int bind_evtchn_to_irqhandler_chip(evtchn_port_t evtchn,
irq_handler_t handler,
unsigned long irqflags,
const char *devname, void *dev_id,
struct irq_chip *chip)
{
int irq, retval;
irq = bind_evtchn_to_irq_chip(evtchn, chip, NULL);
if (irq < 0)
return irq;
retval = request_irq(irq, handler, irqflags, devname, dev_id);
if (retval != 0) {
unbind_from_irq(irq);
return retval;
}
return irq;
}
int bind_evtchn_to_irqhandler(evtchn_port_t evtchn,
irq_handler_t handler,
unsigned long irqflags,
const char *devname, void *dev_id)
{
return bind_evtchn_to_irqhandler_chip(evtchn, handler, irqflags,
devname, dev_id,
&xen_dynamic_chip);
}
EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler);
int bind_evtchn_to_irqhandler_lateeoi(evtchn_port_t evtchn,
irq_handler_t handler,
unsigned long irqflags,
const char *devname, void *dev_id)
{
return bind_evtchn_to_irqhandler_chip(evtchn, handler, irqflags,
devname, dev_id,
&xen_lateeoi_chip);
}
EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler_lateeoi);
static int bind_interdomain_evtchn_to_irqhandler_chip(
struct xenbus_device *dev, evtchn_port_t remote_port,
irq_handler_t handler, unsigned long irqflags,
const char *devname, void *dev_id, struct irq_chip *chip)
{
int irq, retval;
irq = bind_interdomain_evtchn_to_irq_chip(dev, remote_port, chip);
if (irq < 0)
return irq;
retval = request_irq(irq, handler, irqflags, devname, dev_id);
if (retval != 0) {
unbind_from_irq(irq);
return retval;
}
return irq;
}
int bind_interdomain_evtchn_to_irqhandler_lateeoi(struct xenbus_device *dev,
evtchn_port_t remote_port,
irq_handler_t handler,
unsigned long irqflags,
const char *devname,
void *dev_id)
{
return bind_interdomain_evtchn_to_irqhandler_chip(dev,
remote_port, handler, irqflags, devname,
dev_id, &xen_lateeoi_chip);
}
EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irqhandler_lateeoi);
int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
irq_handler_t handler,
unsigned long irqflags, const char *devname, void *dev_id)
{
int irq, retval;
irq = bind_virq_to_irq(virq, cpu, irqflags & IRQF_PERCPU);
if (irq < 0)
return irq;
retval = request_irq(irq, handler, irqflags, devname, dev_id);
if (retval != 0) {
unbind_from_irq(irq);
return retval;
}
return irq;
}
EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);
int bind_ipi_to_irqhandler(enum ipi_vector ipi,
unsigned int cpu,
irq_handler_t handler,
unsigned long irqflags,
const char *devname,
void *dev_id)
{
int irq, retval;
irq = bind_ipi_to_irq(ipi, cpu);
if (irq < 0)
return irq;
irqflags |= IRQF_NO_SUSPEND | IRQF_FORCE_RESUME | IRQF_EARLY_RESUME;
retval = request_irq(irq, handler, irqflags, devname, dev_id);
if (retval != 0) {
unbind_from_irq(irq);
return retval;
}
return irq;
}
void unbind_from_irqhandler(unsigned int irq, void *dev_id)
{
struct irq_info *info = info_for_irq(irq);
if (WARN_ON(!info))
return;
free_irq(irq, dev_id);
unbind_from_irq(irq);
}
EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
/**
* xen_set_irq_priority() - set an event channel priority.
* @irq:irq bound to an event channel.
* @priority: priority between XEN_IRQ_PRIORITY_MAX and XEN_IRQ_PRIORITY_MIN.
*/
int xen_set_irq_priority(unsigned irq, unsigned priority)
{
struct evtchn_set_priority set_priority;
set_priority.port = evtchn_from_irq(irq);
set_priority.priority = priority;
return HYPERVISOR_event_channel_op(EVTCHNOP_set_priority,
&set_priority);
}
EXPORT_SYMBOL_GPL(xen_set_irq_priority);
int evtchn_make_refcounted(evtchn_port_t evtchn)
{
int irq = get_evtchn_to_irq(evtchn);
struct irq_info *info;
if (irq == -1)
return -ENOENT;
info = info_for_irq(irq);
if (!info)
return -ENOENT;
WARN_ON(info->refcnt != -1);
info->refcnt = 1;
return 0;
}
EXPORT_SYMBOL_GPL(evtchn_make_refcounted);
int evtchn_get(evtchn_port_t evtchn)
{
int irq;
struct irq_info *info;
int err = -ENOENT;
if (evtchn >= xen_evtchn_max_channels())
return -EINVAL;
mutex_lock(&irq_mapping_update_lock);
irq = get_evtchn_to_irq(evtchn);
if (irq == -1)
goto done;
info = info_for_irq(irq);
if (!info)
goto done;
err = -EINVAL;
if (info->refcnt <= 0 || info->refcnt == SHRT_MAX)
goto done;
info->refcnt++;
err = 0;
done:
mutex_unlock(&irq_mapping_update_lock);
return err;
}
EXPORT_SYMBOL_GPL(evtchn_get);
void evtchn_put(evtchn_port_t evtchn)
{
int irq = get_evtchn_to_irq(evtchn);
if (WARN_ON(irq == -1))
return;
unbind_from_irq(irq);
}
EXPORT_SYMBOL_GPL(evtchn_put);
void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
{
int irq;
#ifdef CONFIG_X86
if (unlikely(vector == XEN_NMI_VECTOR)) {
int rc = HYPERVISOR_vcpu_op(VCPUOP_send_nmi, xen_vcpu_nr(cpu),
NULL);
if (rc < 0)
printk(KERN_WARNING "Sending nmi to CPU%d failed (rc:%d)\n", cpu, rc);
return;
}
#endif
irq = per_cpu(ipi_to_irq, cpu)[vector];
BUG_ON(irq < 0);
notify_remote_via_irq(irq);
}
struct evtchn_loop_ctrl {
ktime_t timeout;
unsigned count;
bool defer_eoi;
};
void handle_irq_for_port(evtchn_port_t port, struct evtchn_loop_ctrl *ctrl)
{
int irq;
struct irq_info *info;
struct xenbus_device *dev;
irq = get_evtchn_to_irq(port);
if (irq == -1)
return;
/*
* Check for timeout every 256 events.
* We are setting the timeout value only after the first 256
* events in order to not hurt the common case of few loop
* iterations. The 256 is basically an arbitrary value.
*
* In case we are hitting the timeout we need to defer all further
* EOIs in order to ensure to leave the event handling loop rather
* sooner than later.
*/
if (!ctrl->defer_eoi && !(++ctrl->count & 0xff)) {
ktime_t kt = ktime_get();
if (!ctrl->timeout) {
kt = ktime_add_ms(kt,
jiffies_to_msecs(event_loop_timeout));
ctrl->timeout = kt;
} else if (kt > ctrl->timeout) {
ctrl->defer_eoi = true;
}
}
info = info_for_irq(irq);
if (xchg_acquire(&info->is_active, 1))
return;
dev = (info->type == IRQT_EVTCHN) ? info->u.interdomain : NULL;
if (dev)
atomic_inc(&dev->events);
if (ctrl->defer_eoi) {
info->eoi_cpu = smp_processor_id();
info->irq_epoch = __this_cpu_read(irq_epoch);
info->eoi_time = get_jiffies_64() + event_eoi_delay;
}
generic_handle_irq(irq);
}
static int __xen_evtchn_do_upcall(void)
{
struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
int ret = vcpu_info->evtchn_upcall_pending ? IRQ_HANDLED : IRQ_NONE;
int cpu = smp_processor_id();
struct evtchn_loop_ctrl ctrl = { 0 };
read_lock(&evtchn_rwlock);
do {
vcpu_info->evtchn_upcall_pending = 0;
xen_evtchn_handle_events(cpu, &ctrl);
BUG_ON(!irqs_disabled());
virt_rmb(); /* Hypervisor can set upcall pending. */
} while (vcpu_info->evtchn_upcall_pending);
read_unlock(&evtchn_rwlock);
/*
* Increment irq_epoch only now to defer EOIs only for
* xen_irq_lateeoi() invocations occurring from inside the loop
* above.
*/
__this_cpu_inc(irq_epoch);
return ret;
}
void xen_evtchn_do_upcall(struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
irq_enter();
__xen_evtchn_do_upcall();
irq_exit();
set_irq_regs(old_regs);
}
int xen_hvm_evtchn_do_upcall(void)
{
return __xen_evtchn_do_upcall();
}
EXPORT_SYMBOL_GPL(xen_hvm_evtchn_do_upcall);
/* Rebind a new event channel to an existing irq. */
void rebind_evtchn_irq(evtchn_port_t evtchn, int irq)
{
struct irq_info *info = info_for_irq(irq);
if (WARN_ON(!info))
return;
/* Make sure the irq is masked, since the new event channel
will also be masked. */
disable_irq(irq);
mutex_lock(&irq_mapping_update_lock);
/* After resume the irq<->evtchn mappings are all cleared out */
BUG_ON(get_evtchn_to_irq(evtchn) != -1);
/* Expect irq to have been bound before,
so there should be a proper type */
BUG_ON(info->type == IRQT_UNBOUND);
(void)xen_irq_info_evtchn_setup(irq, evtchn, NULL);
mutex_unlock(&irq_mapping_update_lock);
bind_evtchn_to_cpu(evtchn, info->cpu, false);
/* Unmask the event channel. */
enable_irq(irq);
}
/* Rebind an evtchn so that it gets delivered to a specific cpu */
static int xen_rebind_evtchn_to_cpu(struct irq_info *info, unsigned int tcpu)
{
struct evtchn_bind_vcpu bind_vcpu;
evtchn_port_t evtchn = info ? info->evtchn : 0;
if (!VALID_EVTCHN(evtchn))
return -1;
if (!xen_support_evtchn_rebind())
return -1;
/* Send future instances of this interrupt to other vcpu. */
bind_vcpu.port = evtchn;
bind_vcpu.vcpu = xen_vcpu_nr(tcpu);
/*
* Mask the event while changing the VCPU binding to prevent
* it being delivered on an unexpected VCPU.
*/
do_mask(info, EVT_MASK_REASON_TEMPORARY);
/*
* If this fails, it usually just indicates that we're dealing with a
* virq or IPI channel, which don't actually need to be rebound. Ignore
* it, but don't do the xenlinux-level rebind in that case.
*/
if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
bind_evtchn_to_cpu(evtchn, tcpu, false);
do_unmask(info, EVT_MASK_REASON_TEMPORARY);
return 0;
}
/*
* Find the CPU within @dest mask which has the least number of channels
* assigned. This is not precise as the per cpu counts can be modified
* concurrently.
*/
static unsigned int select_target_cpu(const struct cpumask *dest)
{
unsigned int cpu, best_cpu = UINT_MAX, minch = UINT_MAX;
for_each_cpu_and(cpu, dest, cpu_online_mask) {
unsigned int curch = atomic_read(&channels_on_cpu[cpu]);
if (curch < minch) {
minch = curch;
best_cpu = cpu;
}
}
/*
* Catch the unlikely case that dest contains no online CPUs. Can't
* recurse.
*/
if (best_cpu == UINT_MAX)
return select_target_cpu(cpu_online_mask);
return best_cpu;
}
static int set_affinity_irq(struct irq_data *data, const struct cpumask *dest,
bool force)
{
unsigned int tcpu = select_target_cpu(dest);
int ret;
ret = xen_rebind_evtchn_to_cpu(info_for_irq(data->irq), tcpu);
if (!ret)
irq_data_update_effective_affinity(data, cpumask_of(tcpu));
return ret;
}
static void enable_dynirq(struct irq_data *data)
{
struct irq_info *info = info_for_irq(data->irq);
evtchn_port_t evtchn = info ? info->evtchn : 0;
if (VALID_EVTCHN(evtchn))
do_unmask(info, EVT_MASK_REASON_EXPLICIT);
}
static void disable_dynirq(struct irq_data *data)
{
struct irq_info *info = info_for_irq(data->irq);
evtchn_port_t evtchn = info ? info->evtchn : 0;
if (VALID_EVTCHN(evtchn))
do_mask(info, EVT_MASK_REASON_EXPLICIT);
}
static void ack_dynirq(struct irq_data *data)
{
struct irq_info *info = info_for_irq(data->irq);
evtchn_port_t evtchn = info ? info->evtchn : 0;
if (VALID_EVTCHN(evtchn))
event_handler_exit(info);
}
static void mask_ack_dynirq(struct irq_data *data)
{
disable_dynirq(data);
ack_dynirq(data);
}
static void lateeoi_ack_dynirq(struct irq_data *data)
{
struct irq_info *info = info_for_irq(data->irq);
evtchn_port_t evtchn = info ? info->evtchn : 0;
if (VALID_EVTCHN(evtchn)) {
do_mask(info, EVT_MASK_REASON_EOI_PENDING);
/*
* Don't call event_handler_exit().
* Need to keep is_active non-zero in order to ignore re-raised
* events after cpu affinity changes while a lateeoi is pending.
*/
clear_evtchn(evtchn);
}
}
static void lateeoi_mask_ack_dynirq(struct irq_data *data)
{
struct irq_info *info = info_for_irq(data->irq);
evtchn_port_t evtchn = info ? info->evtchn : 0;
if (VALID_EVTCHN(evtchn)) {
do_mask(info, EVT_MASK_REASON_EXPLICIT);
event_handler_exit(info);
}
}
static int retrigger_dynirq(struct irq_data *data)
{
struct irq_info *info = info_for_irq(data->irq);
evtchn_port_t evtchn = info ? info->evtchn : 0;
if (!VALID_EVTCHN(evtchn))
return 0;
do_mask(info, EVT_MASK_REASON_TEMPORARY);
set_evtchn(evtchn);
do_unmask(info, EVT_MASK_REASON_TEMPORARY);
return 1;
}
static void restore_pirqs(void)
{
int pirq, rc, irq, gsi;
struct physdev_map_pirq map_irq;
struct irq_info *info;
list_for_each_entry(info, &xen_irq_list_head, list) {
if (info->type != IRQT_PIRQ)
continue;
pirq = info->u.pirq.pirq;
gsi = info->u.pirq.gsi;
irq = info->irq;
/* save/restore of PT devices doesn't work, so at this point the
* only devices present are GSI based emulated devices */
if (!gsi)
continue;
map_irq.domid = DOMID_SELF;
map_irq.type = MAP_PIRQ_TYPE_GSI;
map_irq.index = gsi;
map_irq.pirq = pirq;
rc = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq, &map_irq);
if (rc) {
pr_warn("xen map irq failed gsi=%d irq=%d pirq=%d rc=%d\n",
gsi, irq, pirq, rc);
xen_free_irq(irq);
continue;
}
printk(KERN_DEBUG "xen: --> irq=%d, pirq=%d\n", irq, map_irq.pirq);
__startup_pirq(irq);
}
}
static void restore_cpu_virqs(unsigned int cpu)
{
struct evtchn_bind_virq bind_virq;
evtchn_port_t evtchn;
int virq, irq;
for (virq = 0; virq < NR_VIRQS; virq++) {
if ((irq = per_cpu(virq_to_irq, cpu)[virq]) == -1)
continue;
BUG_ON(virq_from_irq(irq) != virq);
/* Get a new binding from Xen. */
bind_virq.virq = virq;
bind_virq.vcpu = xen_vcpu_nr(cpu);
if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
&bind_virq) != 0)
BUG();
evtchn = bind_virq.port;
/* Record the new mapping. */
(void)xen_irq_info_virq_setup(cpu, irq, evtchn, virq);
/* The affinity mask is still valid */
bind_evtchn_to_cpu(evtchn, cpu, false);
}
}
static void restore_cpu_ipis(unsigned int cpu)
{
struct evtchn_bind_ipi bind_ipi;
evtchn_port_t evtchn;
int ipi, irq;
for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) {
if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1)
continue;
BUG_ON(ipi_from_irq(irq) != ipi);
/* Get a new binding from Xen. */
bind_ipi.vcpu = xen_vcpu_nr(cpu);
if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
&bind_ipi) != 0)
BUG();
evtchn = bind_ipi.port;
/* Record the new mapping. */
(void)xen_irq_info_ipi_setup(cpu, irq, evtchn, ipi);
/* The affinity mask is still valid */
bind_evtchn_to_cpu(evtchn, cpu, false);
}
}
/* Clear an irq's pending state, in preparation for polling on it */
void xen_clear_irq_pending(int irq)
{
struct irq_info *info = info_for_irq(irq);
evtchn_port_t evtchn = info ? info->evtchn : 0;
if (VALID_EVTCHN(evtchn))
event_handler_exit(info);
}
EXPORT_SYMBOL(xen_clear_irq_pending);
void xen_set_irq_pending(int irq)
{
evtchn_port_t evtchn = evtchn_from_irq(irq);
if (VALID_EVTCHN(evtchn))
set_evtchn(evtchn);
}
bool xen_test_irq_pending(int irq)
{
evtchn_port_t evtchn = evtchn_from_irq(irq);
bool ret = false;
if (VALID_EVTCHN(evtchn))
ret = test_evtchn(evtchn);
return ret;
}
/* Poll waiting for an irq to become pending with timeout. In the usual case,
* the irq will be disabled so it won't deliver an interrupt. */
void xen_poll_irq_timeout(int irq, u64 timeout)
{
evtchn_port_t evtchn = evtchn_from_irq(irq);
if (VALID_EVTCHN(evtchn)) {
struct sched_poll poll;
poll.nr_ports = 1;
poll.timeout = timeout;
set_xen_guest_handle(poll.ports, &evtchn);
if (HYPERVISOR_sched_op(SCHEDOP_poll, &poll) != 0)
BUG();
}
}
EXPORT_SYMBOL(xen_poll_irq_timeout);
/* Poll waiting for an irq to become pending. In the usual case, the
* irq will be disabled so it won't deliver an interrupt. */
void xen_poll_irq(int irq)
{
xen_poll_irq_timeout(irq, 0 /* no timeout */);
}
/* Check whether the IRQ line is shared with other guests. */
int xen_test_irq_shared(int irq)
{
struct irq_info *info = info_for_irq(irq);
struct physdev_irq_status_query irq_status;
if (WARN_ON(!info))
return -ENOENT;
irq_status.irq = info->u.pirq.pirq;
if (HYPERVISOR_physdev_op(PHYSDEVOP_irq_status_query, &irq_status))
return 0;
return !(irq_status.flags & XENIRQSTAT_shared);
}
EXPORT_SYMBOL_GPL(xen_test_irq_shared);
void xen_irq_resume(void)
{
unsigned int cpu;
struct irq_info *info;
/* New event-channel space is not 'live' yet. */
xen_evtchn_resume();
/* No IRQ <-> event-channel mappings. */
list_for_each_entry(info, &xen_irq_list_head, list) {
/* Zap event-channel binding */
info->evtchn = 0;
/* Adjust accounting */
channels_on_cpu_dec(info);
}
clear_evtchn_to_irq_all();
for_each_possible_cpu(cpu) {
restore_cpu_virqs(cpu);
restore_cpu_ipis(cpu);
}
restore_pirqs();
}
static struct irq_chip xen_dynamic_chip __read_mostly = {
.name = "xen-dyn",
.irq_disable = disable_dynirq,
.irq_mask = disable_dynirq,
.irq_unmask = enable_dynirq,
.irq_ack = ack_dynirq,
.irq_mask_ack = mask_ack_dynirq,
.irq_set_affinity = set_affinity_irq,
.irq_retrigger = retrigger_dynirq,
};
static struct irq_chip xen_lateeoi_chip __read_mostly = {
/* The chip name needs to contain "xen-dyn" for irqbalance to work. */
.name = "xen-dyn-lateeoi",
.irq_disable = disable_dynirq,
.irq_mask = disable_dynirq,
.irq_unmask = enable_dynirq,
.irq_ack = lateeoi_ack_dynirq,
.irq_mask_ack = lateeoi_mask_ack_dynirq,
.irq_set_affinity = set_affinity_irq,
.irq_retrigger = retrigger_dynirq,
};
static struct irq_chip xen_pirq_chip __read_mostly = {
.name = "xen-pirq",
.irq_startup = startup_pirq,
.irq_shutdown = shutdown_pirq,
.irq_enable = enable_pirq,
.irq_disable = disable_pirq,
.irq_mask = disable_dynirq,
.irq_unmask = enable_dynirq,
.irq_ack = eoi_pirq,
.irq_eoi = eoi_pirq,
.irq_mask_ack = mask_ack_pirq,
.irq_set_affinity = set_affinity_irq,
.irq_retrigger = retrigger_dynirq,
};
static struct irq_chip xen_percpu_chip __read_mostly = {
.name = "xen-percpu",
.irq_disable = disable_dynirq,
.irq_mask = disable_dynirq,
.irq_unmask = enable_dynirq,
.irq_ack = ack_dynirq,
};
#ifdef CONFIG_X86
#ifdef CONFIG_XEN_PVHVM
/* Vector callbacks are better than PCI interrupts to receive event
* channel notifications because we can receive vector callbacks on any
* vcpu and we don't need PCI support or APIC interactions. */
void xen_setup_callback_vector(void)
{
uint64_t callback_via;
if (xen_have_vector_callback) {
callback_via = HVM_CALLBACK_VECTOR(HYPERVISOR_CALLBACK_VECTOR);
if (xen_set_callback_via(callback_via)) {
pr_err("Request for Xen HVM callback vector failed\n");
xen_have_vector_callback = false;
}
}
}
/*
* Setup per-vCPU vector-type callbacks. If this setup is unavailable,
* fallback to the global vector-type callback.
*/
static __init void xen_init_setup_upcall_vector(void)
{
if (!xen_have_vector_callback)
return;
if ((cpuid_eax(xen_cpuid_base() + 4) & XEN_HVM_CPUID_UPCALL_VECTOR) &&
!xen_set_upcall_vector(0))
xen_percpu_upcall = true;
else if (xen_feature(XENFEAT_hvm_callback_vector))
xen_setup_callback_vector();
else
xen_have_vector_callback = false;
}
int xen_set_upcall_vector(unsigned int cpu)
{
int rc;
xen_hvm_evtchn_upcall_vector_t op = {
.vector = HYPERVISOR_CALLBACK_VECTOR,
.vcpu = per_cpu(xen_vcpu_id, cpu),
};
rc = HYPERVISOR_hvm_op(HVMOP_set_evtchn_upcall_vector, &op);
if (rc)
return rc;
/* Trick toolstack to think we are enlightened. */
if (!cpu)
rc = xen_set_callback_via(1);
return rc;
}
static __init void xen_alloc_callback_vector(void)
{
if (!xen_have_vector_callback)
return;
pr_info("Xen HVM callback vector for event delivery is enabled\n");
alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_xen_hvm_callback);
}
#else
void xen_setup_callback_vector(void) {}
static inline void xen_init_setup_upcall_vector(void) {}
int xen_set_upcall_vector(unsigned int cpu) {}
static inline void xen_alloc_callback_vector(void) {}
#endif /* CONFIG_XEN_PVHVM */
#endif /* CONFIG_X86 */
bool xen_fifo_events = true;
module_param_named(fifo_events, xen_fifo_events, bool, 0);
static int xen_evtchn_cpu_prepare(unsigned int cpu)
{
int ret = 0;
xen_cpu_init_eoi(cpu);
if (evtchn_ops->percpu_init)
ret = evtchn_ops->percpu_init(cpu);
return ret;
}
static int xen_evtchn_cpu_dead(unsigned int cpu)
{
int ret = 0;
if (evtchn_ops->percpu_deinit)
ret = evtchn_ops->percpu_deinit(cpu);
return ret;
}
void __init xen_init_IRQ(void)
{
int ret = -EINVAL;
evtchn_port_t evtchn;
if (xen_fifo_events)
ret = xen_evtchn_fifo_init();
if (ret < 0) {
xen_evtchn_2l_init();
xen_fifo_events = false;
}
xen_cpu_init_eoi(smp_processor_id());
cpuhp_setup_state_nocalls(CPUHP_XEN_EVTCHN_PREPARE,
"xen/evtchn:prepare",
xen_evtchn_cpu_prepare, xen_evtchn_cpu_dead);
evtchn_to_irq = kcalloc(EVTCHN_ROW(xen_evtchn_max_channels()),
sizeof(*evtchn_to_irq), GFP_KERNEL);
BUG_ON(!evtchn_to_irq);
/* No event channels are 'live' right now. */
for (evtchn = 0; evtchn < xen_evtchn_nr_channels(); evtchn++)
mask_evtchn(evtchn);
pirq_needs_eoi = pirq_needs_eoi_flag;
#ifdef CONFIG_X86
if (xen_pv_domain()) {
if (xen_initial_domain())
pci_xen_initial_domain();
}
xen_init_setup_upcall_vector();
xen_alloc_callback_vector();
if (xen_hvm_domain()) {
native_init_IRQ();
/* pci_xen_hvm_init must be called after native_init_IRQ so that
* __acpi_register_gsi can point at the right function */
pci_xen_hvm_init();
} else {
int rc;
struct physdev_pirq_eoi_gmfn eoi_gmfn;
pirq_eoi_map = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
eoi_gmfn.gmfn = virt_to_gfn(pirq_eoi_map);
rc = HYPERVISOR_physdev_op(PHYSDEVOP_pirq_eoi_gmfn_v2, &eoi_gmfn);
if (rc != 0) {
free_page((unsigned long) pirq_eoi_map);
pirq_eoi_map = NULL;
} else
pirq_needs_eoi = pirq_check_eoi_map;
}
#endif
}
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