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alistair23-linux/virt/kvm/irq_comm.c
Alex Williamson 7a84428af7 KVM: Add resampling irqfds for level triggered interrupts 
To emulate level triggered interrupts, add a resample option to
KVM_IRQFD.  When specified, a new resamplefd is provided that notifies
the user when the irqchip has been resampled by the VM.  This may, for
instance, indicate an EOI.  Also in this mode, posting of an interrupt
through an irqfd only asserts the interrupt.  On resampling, the
interrupt is automatically de-asserted prior to user notification.
This enables level triggered interrupts to be posted and re-enabled
from vfio with no userspace intervention.

All resampling irqfds can make use of a single irq source ID, so we
reserve a new one for this interface.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-23 13:50:15 +02:00

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/*
* irq_comm.c: Common API for in kernel interrupt controller
* Copyright (c) 2007, Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
* Place - Suite 330, Boston, MA 02111-1307 USA.
* Authors:
* Yaozu (Eddie) Dong <Eddie.dong@intel.com>
*
* Copyright 2010 Red Hat, Inc. and/or its affiliates.
*/
#include <linux/kvm_host.h>
#include <linux/slab.h>
#include <trace/events/kvm.h>
#include <asm/msidef.h>
#ifdef CONFIG_IA64
#include <asm/iosapic.h>
#endif
#include "irq.h"
#include "ioapic.h"
static int kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
struct kvm *kvm, int irq_source_id, int level)
{
#ifdef CONFIG_X86
struct kvm_pic *pic = pic_irqchip(kvm);
return kvm_pic_set_irq(pic, e->irqchip.pin, irq_source_id, level);
#else
return -1;
#endif
}
static int kvm_set_ioapic_irq(struct kvm_kernel_irq_routing_entry *e,
struct kvm *kvm, int irq_source_id, int level)
{
struct kvm_ioapic *ioapic = kvm->arch.vioapic;
return kvm_ioapic_set_irq(ioapic, e->irqchip.pin, irq_source_id, level);
}
inline static bool kvm_is_dm_lowest_prio(struct kvm_lapic_irq *irq)
{
#ifdef CONFIG_IA64
return irq->delivery_mode ==
(IOSAPIC_LOWEST_PRIORITY << IOSAPIC_DELIVERY_SHIFT);
#else
return irq->delivery_mode == APIC_DM_LOWEST;
#endif
}
int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
struct kvm_lapic_irq *irq)
{
int i, r = -1;
struct kvm_vcpu *vcpu, *lowest = NULL;
if (irq->dest_mode == 0 && irq->dest_id == 0xff &&
kvm_is_dm_lowest_prio(irq)) {
printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n");
irq->delivery_mode = APIC_DM_FIXED;
}
if (kvm_irq_delivery_to_apic_fast(kvm, src, irq, &r))
return r;
kvm_for_each_vcpu(i, vcpu, kvm) {
if (!kvm_apic_present(vcpu))
continue;
if (!kvm_apic_match_dest(vcpu, src, irq->shorthand,
irq->dest_id, irq->dest_mode))
continue;
if (!kvm_is_dm_lowest_prio(irq)) {
if (r < 0)
r = 0;
r += kvm_apic_set_irq(vcpu, irq);
} else if (kvm_lapic_enabled(vcpu)) {
if (!lowest)
lowest = vcpu;
else if (kvm_apic_compare_prio(vcpu, lowest) < 0)
lowest = vcpu;
}
}
if (lowest)
r = kvm_apic_set_irq(lowest, irq);
return r;
}
int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
struct kvm *kvm, int irq_source_id, int level)
{
struct kvm_lapic_irq irq;
if (!level)
return -1;
trace_kvm_msi_set_irq(e->msi.address_lo, e->msi.data);
irq.dest_id = (e->msi.address_lo &
MSI_ADDR_DEST_ID_MASK) >> MSI_ADDR_DEST_ID_SHIFT;
irq.vector = (e->msi.data &
MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT;
irq.dest_mode = (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo;
irq.trig_mode = (1 << MSI_DATA_TRIGGER_SHIFT) & e->msi.data;
irq.delivery_mode = e->msi.data & 0x700;
irq.level = 1;
irq.shorthand = 0;
/* TODO Deal with RH bit of MSI message address */
return kvm_irq_delivery_to_apic(kvm, NULL, &irq);
}
int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
{
struct kvm_kernel_irq_routing_entry route;
if (!irqchip_in_kernel(kvm) || msi->flags != 0)
return -EINVAL;
route.msi.address_lo = msi->address_lo;
route.msi.address_hi = msi->address_hi;
route.msi.data = msi->data;
return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1);
}
/*
* Return value:
* < 0 Interrupt was ignored (masked or not delivered for other reasons)
* = 0 Interrupt was coalesced (previous irq is still pending)
* > 0 Number of CPUs interrupt was delivered to
*/
int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level)
{
struct kvm_kernel_irq_routing_entry *e, irq_set[KVM_NR_IRQCHIPS];
int ret = -1, i = 0;
struct kvm_irq_routing_table *irq_rt;
struct hlist_node *n;
trace_kvm_set_irq(irq, level, irq_source_id);
/* Not possible to detect if the guest uses the PIC or the
* IOAPIC. So set the bit in both. The guest will ignore
* writes to the unused one.
*/
rcu_read_lock();
irq_rt = rcu_dereference(kvm->irq_routing);
if (irq < irq_rt->nr_rt_entries)
hlist_for_each_entry(e, n, &irq_rt->map[irq], link)
irq_set[i++] = *e;
rcu_read_unlock();
while(i--) {
int r;
r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level);
if (r < 0)
continue;
ret = r + ((ret < 0) ? 0 : ret);
}
return ret;
}
void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
{
struct kvm_irq_ack_notifier *kian;
struct hlist_node *n;
int gsi;
trace_kvm_ack_irq(irqchip, pin);
rcu_read_lock();
gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
if (gsi != -1)
hlist_for_each_entry_rcu(kian, n, &kvm->irq_ack_notifier_list,
link)
if (kian->gsi == gsi)
kian->irq_acked(kian);
rcu_read_unlock();
}
void kvm_register_irq_ack_notifier(struct kvm *kvm,
struct kvm_irq_ack_notifier *kian)
{
mutex_lock(&kvm->irq_lock);
hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list);
mutex_unlock(&kvm->irq_lock);
}
void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
struct kvm_irq_ack_notifier *kian)
{
mutex_lock(&kvm->irq_lock);
hlist_del_init_rcu(&kian->link);
mutex_unlock(&kvm->irq_lock);
synchronize_rcu();
}
int kvm_request_irq_source_id(struct kvm *kvm)
{
unsigned long *bitmap = &kvm->arch.irq_sources_bitmap;
int irq_source_id;
mutex_lock(&kvm->irq_lock);
irq_source_id = find_first_zero_bit(bitmap, BITS_PER_LONG);
if (irq_source_id >= BITS_PER_LONG) {
printk(KERN_WARNING "kvm: exhaust allocatable IRQ sources!\n");
irq_source_id = -EFAULT;
goto unlock;
}
ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
#ifdef CONFIG_X86
ASSERT(irq_source_id != KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID);
#endif
set_bit(irq_source_id, bitmap);
unlock:
mutex_unlock(&kvm->irq_lock);
return irq_source_id;
}
void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
{
ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
#ifdef CONFIG_X86
ASSERT(irq_source_id != KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID);
#endif
mutex_lock(&kvm->irq_lock);
if (irq_source_id < 0 ||
irq_source_id >= BITS_PER_LONG) {
printk(KERN_ERR "kvm: IRQ source ID out of range!\n");
goto unlock;
}
clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap);
if (!irqchip_in_kernel(kvm))
goto unlock;
kvm_ioapic_clear_all(kvm->arch.vioapic, irq_source_id);
#ifdef CONFIG_X86
kvm_pic_clear_all(pic_irqchip(kvm), irq_source_id);
#endif
unlock:
mutex_unlock(&kvm->irq_lock);
}
void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
struct kvm_irq_mask_notifier *kimn)
{
mutex_lock(&kvm->irq_lock);
kimn->irq = irq;
hlist_add_head_rcu(&kimn->link, &kvm->mask_notifier_list);
mutex_unlock(&kvm->irq_lock);
}
void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
struct kvm_irq_mask_notifier *kimn)
{
mutex_lock(&kvm->irq_lock);
hlist_del_rcu(&kimn->link);
mutex_unlock(&kvm->irq_lock);
synchronize_rcu();
}
void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin,
bool mask)
{
struct kvm_irq_mask_notifier *kimn;
struct hlist_node *n;
int gsi;
rcu_read_lock();
gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
if (gsi != -1)
hlist_for_each_entry_rcu(kimn, n, &kvm->mask_notifier_list, link)
if (kimn->irq == gsi)
kimn->func(kimn, mask);
rcu_read_unlock();
}
void kvm_free_irq_routing(struct kvm *kvm)
{
/* Called only during vm destruction. Nobody can use the pointer
at this stage */
kfree(kvm->irq_routing);
}
static int setup_routing_entry(struct kvm_irq_routing_table *rt,
struct kvm_kernel_irq_routing_entry *e,
const struct kvm_irq_routing_entry *ue)
{
int r = -EINVAL;
int delta;
unsigned max_pin;
struct kvm_kernel_irq_routing_entry *ei;
struct hlist_node *n;
/*
* Do not allow GSI to be mapped to the same irqchip more than once.
* Allow only one to one mapping between GSI and MSI.
*/
hlist_for_each_entry(ei, n, &rt->map[ue->gsi], link)
if (ei->type == KVM_IRQ_ROUTING_MSI ||
ue->type == KVM_IRQ_ROUTING_MSI ||
ue->u.irqchip.irqchip == ei->irqchip.irqchip)
return r;
e->gsi = ue->gsi;
e->type = ue->type;
switch (ue->type) {
case KVM_IRQ_ROUTING_IRQCHIP:
delta = 0;
switch (ue->u.irqchip.irqchip) {
case KVM_IRQCHIP_PIC_MASTER:
e->set = kvm_set_pic_irq;
max_pin = PIC_NUM_PINS;
break;
case KVM_IRQCHIP_PIC_SLAVE:
e->set = kvm_set_pic_irq;
max_pin = PIC_NUM_PINS;
delta = 8;
break;
case KVM_IRQCHIP_IOAPIC:
max_pin = KVM_IOAPIC_NUM_PINS;
e->set = kvm_set_ioapic_irq;
break;
default:
goto out;
}
e->irqchip.irqchip = ue->u.irqchip.irqchip;
e->irqchip.pin = ue->u.irqchip.pin + delta;
if (e->irqchip.pin >= max_pin)
goto out;
rt->chip[ue->u.irqchip.irqchip][e->irqchip.pin] = ue->gsi;
break;
case KVM_IRQ_ROUTING_MSI:
e->set = kvm_set_msi;
e->msi.address_lo = ue->u.msi.address_lo;
e->msi.address_hi = ue->u.msi.address_hi;
e->msi.data = ue->u.msi.data;
break;
default:
goto out;
}
hlist_add_head(&e->link, &rt->map[e->gsi]);
r = 0;
out:
return r;
}
int kvm_set_irq_routing(struct kvm *kvm,
const struct kvm_irq_routing_entry *ue,
unsigned nr,
unsigned flags)
{
struct kvm_irq_routing_table *new, *old;
u32 i, j, nr_rt_entries = 0;
int r;
for (i = 0; i < nr; ++i) {
if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
return -EINVAL;
nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
}
nr_rt_entries += 1;
new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head))
+ (nr * sizeof(struct kvm_kernel_irq_routing_entry)),
GFP_KERNEL);
if (!new)
return -ENOMEM;
new->rt_entries = (void *)&new->map[nr_rt_entries];
new->nr_rt_entries = nr_rt_entries;
for (i = 0; i < 3; i++)
for (j = 0; j < KVM_IOAPIC_NUM_PINS; j++)
new->chip[i][j] = -1;
for (i = 0; i < nr; ++i) {
r = -EINVAL;
if (ue->flags)
goto out;
r = setup_routing_entry(new, &new->rt_entries[i], ue);
if (r)
goto out;
++ue;
}
mutex_lock(&kvm->irq_lock);
old = kvm->irq_routing;
kvm_irq_routing_update(kvm, new);
mutex_unlock(&kvm->irq_lock);
synchronize_rcu();
new = old;
r = 0;
out:
kfree(new);
return r;
}
#define IOAPIC_ROUTING_ENTRY(irq) \
{ .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP, \
.u.irqchip.irqchip = KVM_IRQCHIP_IOAPIC, .u.irqchip.pin = (irq) }
#define ROUTING_ENTRY1(irq) IOAPIC_ROUTING_ENTRY(irq)
#ifdef CONFIG_X86
# define PIC_ROUTING_ENTRY(irq) \
{ .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP, \
.u.irqchip.irqchip = SELECT_PIC(irq), .u.irqchip.pin = (irq) % 8 }
# define ROUTING_ENTRY2(irq) \
IOAPIC_ROUTING_ENTRY(irq), PIC_ROUTING_ENTRY(irq)
#else
# define ROUTING_ENTRY2(irq) \
IOAPIC_ROUTING_ENTRY(irq)
#endif
static const struct kvm_irq_routing_entry default_routing[] = {
ROUTING_ENTRY2(0), ROUTING_ENTRY2(1),
ROUTING_ENTRY2(2), ROUTING_ENTRY2(3),
ROUTING_ENTRY2(4), ROUTING_ENTRY2(5),
ROUTING_ENTRY2(6), ROUTING_ENTRY2(7),
ROUTING_ENTRY2(8), ROUTING_ENTRY2(9),
ROUTING_ENTRY2(10), ROUTING_ENTRY2(11),
ROUTING_ENTRY2(12), ROUTING_ENTRY2(13),
ROUTING_ENTRY2(14), ROUTING_ENTRY2(15),
ROUTING_ENTRY1(16), ROUTING_ENTRY1(17),
ROUTING_ENTRY1(18), ROUTING_ENTRY1(19),
ROUTING_ENTRY1(20), ROUTING_ENTRY1(21),
ROUTING_ENTRY1(22), ROUTING_ENTRY1(23),
#ifdef CONFIG_IA64
ROUTING_ENTRY1(24), ROUTING_ENTRY1(25),
ROUTING_ENTRY1(26), ROUTING_ENTRY1(27),
ROUTING_ENTRY1(28), ROUTING_ENTRY1(29),
ROUTING_ENTRY1(30), ROUTING_ENTRY1(31),
ROUTING_ENTRY1(32), ROUTING_ENTRY1(33),
ROUTING_ENTRY1(34), ROUTING_ENTRY1(35),
ROUTING_ENTRY1(36), ROUTING_ENTRY1(37),
ROUTING_ENTRY1(38), ROUTING_ENTRY1(39),
ROUTING_ENTRY1(40), ROUTING_ENTRY1(41),
ROUTING_ENTRY1(42), ROUTING_ENTRY1(43),
ROUTING_ENTRY1(44), ROUTING_ENTRY1(45),
ROUTING_ENTRY1(46), ROUTING_ENTRY1(47),
#endif
};
int kvm_setup_default_irq_routing(struct kvm *kvm)
{
return kvm_set_irq_routing(kvm, default_routing,
ARRAY_SIZE(default_routing), 0);
}
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