diff options
Diffstat (limited to 'drivers/xen/events/events_base.c')
| -rw-r--r-- | drivers/xen/events/events_base.c | 2333 |
1 files changed, 2333 insertions, 0 deletions
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c new file mode 100644 index 000000000..00f8e3499 --- /dev/null +++ b/drivers/xen/events/events_base.c @@ -0,0 +1,2333 @@ +// 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/rcupdate.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; + struct rcu_work rwork; + 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 hierarchy: + * + * irq_mapping_update_lock + * 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; +} + +static void delayed_free_irq(struct work_struct *work) +{ + struct irq_info *info = container_of(to_rcu_work(work), struct irq_info, + rwork); + unsigned int irq = info->irq; + + /* Remove the info pointer only now, with no potential users left. */ + set_info_for_irq(irq, NULL); + + kfree(info); + + /* Legacy IRQ descriptors are managed by the arch. */ + if (irq >= nr_legacy_irqs()) + irq_free_desc(irq); +} + +/* 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); + + elem = list_first_entry_or_null(&eoi->eoi_list, struct irq_info, + eoi_list); + if (!elem || info->eoi_time < elem->eoi_time) { + 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); + + rcu_read_lock(); + + while (true) { + spin_lock_irqsave(&eoi->eoi_list_lock, flags); + + info = list_first_entry_or_null(&eoi->eoi_list, struct irq_info, + eoi_list); + + if (info == NULL) + break; + + if (now < info->eoi_time) { + mod_delayed_work_on(info->eoi_cpu, system_wq, + &eoi->delayed, + info->eoi_time - now); + break; + } + + list_del_init(&info->eoi_list); + + spin_unlock_irqrestore(&eoi->eoi_list_lock, flags); + + info->eoi_time = 0; + + xen_irq_lateeoi_locked(info, false); + } + + spin_unlock_irqrestore(&eoi->eoi_list_lock, flags); + + rcu_read_unlock(); +} + +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; + + rcu_read_lock(); + + info = info_for_irq(irq); + + if (info) + xen_irq_lateeoi_locked(info, eoi_flags & XEN_EOI_FLAG_SPURIOUS); + + rcu_read_unlock(); +} +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; + INIT_RCU_WORK(&info->rwork, delayed_free_irq); + + 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); + + if (WARN_ON(!info)) + return; + + if (!list_empty(&info->eoi_list)) + lateeoi_list_del(info); + + list_del(&info->list); + + WARN_ON(info->refcnt > 0); + + queue_rcu_work(system_wq, &info->rwork); +} + +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); +} + +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 }; + + /* + * When closing an event channel the associated IRQ must not be freed + * until all cpus have left the event handling loop. This is ensured + * by taking the rcu_read_lock() while handling events, as freeing of + * the IRQ is handled via queue_rcu_work() _after_ closing the event + * channel. + */ + rcu_read_lock(); + + 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); + + rcu_read_unlock(); + + /* + * 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; +} +EXPORT_SYMBOL_GPL(xen_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 +} |