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-rw-r--r--virt/kvm/eventfd.c68
1 files changed, 53 insertions, 15 deletions
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 29c2a04..20c3af7 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -31,6 +31,7 @@
#include <linux/list.h>
#include <linux/eventfd.h>
#include <linux/kernel.h>
+#include <linux/srcu.h>
#include <linux/slab.h>
#include "iodev.h"
@@ -118,19 +119,22 @@ static void
irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian)
{
struct _irqfd_resampler *resampler;
+ struct kvm *kvm;
struct _irqfd *irqfd;
+ int idx;
resampler = container_of(kian, struct _irqfd_resampler, notifier);
+ kvm = resampler->kvm;
- kvm_set_irq(resampler->kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
+ kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
resampler->notifier.gsi, 0, false);
- rcu_read_lock();
+ idx = srcu_read_lock(&kvm->irq_srcu);
list_for_each_entry_rcu(irqfd, &resampler->list, resampler_link)
eventfd_signal(irqfd->resamplefd, 1);
- rcu_read_unlock();
+ srcu_read_unlock(&kvm->irq_srcu, idx);
}
static void
@@ -142,7 +146,7 @@ irqfd_resampler_shutdown(struct _irqfd *irqfd)
mutex_lock(&kvm->irqfds.resampler_lock);
list_del_rcu(&irqfd->resampler_link);
- synchronize_rcu();
+ synchronize_srcu(&kvm->irq_srcu);
if (list_empty(&resampler->list)) {
list_del(&resampler->link);
@@ -221,17 +225,18 @@ irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
unsigned long flags = (unsigned long)key;
struct kvm_kernel_irq_routing_entry *irq;
struct kvm *kvm = irqfd->kvm;
+ int idx;
if (flags & POLLIN) {
- rcu_read_lock();
- irq = rcu_dereference(irqfd->irq_entry);
+ idx = srcu_read_lock(&kvm->irq_srcu);
+ irq = srcu_dereference(irqfd->irq_entry, &kvm->irq_srcu);
/* An event has been signaled, inject an interrupt */
if (irq)
kvm_set_msi(irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1,
false);
else
schedule_work(&irqfd->inject);
- rcu_read_unlock();
+ srcu_read_unlock(&kvm->irq_srcu, idx);
}
if (flags & POLLHUP) {
@@ -363,7 +368,7 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
}
list_add_rcu(&irqfd->resampler_link, &irqfd->resampler->list);
- synchronize_rcu();
+ synchronize_srcu(&kvm->irq_srcu);
mutex_unlock(&kvm->irqfds.resampler_lock);
}
@@ -465,7 +470,7 @@ kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
* another thread calls kvm_irq_routing_update before
* we flush workqueue below (we synchronize with
* kvm_irq_routing_update using irqfds.lock).
- * It is paired with synchronize_rcu done by caller
+ * It is paired with synchronize_srcu done by caller
* of that function.
*/
rcu_assign_pointer(irqfd->irq_entry, NULL);
@@ -524,7 +529,7 @@ kvm_irqfd_release(struct kvm *kvm)
/*
* Change irq_routing and irqfd.
- * Caller must invoke synchronize_rcu afterwards.
+ * Caller must invoke synchronize_srcu(&kvm->irq_srcu) afterwards.
*/
void kvm_irq_routing_update(struct kvm *kvm,
struct kvm_irq_routing_table *irq_rt)
@@ -600,7 +605,15 @@ ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
{
u64 _val;
- if (!(addr == p->addr && len == p->length))
+ if (addr != p->addr)
+ /* address must be precise for a hit */
+ return false;
+
+ if (!p->length)
+ /* length = 0 means only look at the address, so always a hit */
+ return true;
+
+ if (len != p->length)
/* address-range must be precise for a hit */
return false;
@@ -671,9 +684,11 @@ ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
list_for_each_entry(_p, &kvm->ioeventfds, list)
if (_p->bus_idx == p->bus_idx &&
- _p->addr == p->addr && _p->length == p->length &&
- (_p->wildcard || p->wildcard ||
- _p->datamatch == p->datamatch))
+ _p->addr == p->addr &&
+ (!_p->length || !p->length ||
+ (_p->length == p->length &&
+ (_p->wildcard || p->wildcard ||
+ _p->datamatch == p->datamatch))))
return true;
return false;
@@ -697,8 +712,9 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
int ret;
bus_idx = ioeventfd_bus_from_flags(args->flags);
- /* must be natural-word sized */
+ /* must be natural-word sized, or 0 to ignore length */
switch (args->len) {
+ case 0:
case 1:
case 2:
case 4:
@@ -716,6 +732,12 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK)
return -EINVAL;
+ /* ioeventfd with no length can't be combined with DATAMATCH */
+ if (!args->len &&
+ args->flags & (KVM_IOEVENTFD_FLAG_PIO |
+ KVM_IOEVENTFD_FLAG_DATAMATCH))
+ return -EINVAL;
+
eventfd = eventfd_ctx_fdget(args->fd);
if (IS_ERR(eventfd))
return PTR_ERR(eventfd);
@@ -753,6 +775,16 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
if (ret < 0)
goto unlock_fail;
+ /* When length is ignored, MMIO is also put on a separate bus, for
+ * faster lookups.
+ */
+ if (!args->len && !(args->flags & KVM_IOEVENTFD_FLAG_PIO)) {
+ ret = kvm_io_bus_register_dev(kvm, KVM_FAST_MMIO_BUS,
+ p->addr, 0, &p->dev);
+ if (ret < 0)
+ goto register_fail;
+ }
+
kvm->buses[bus_idx]->ioeventfd_count++;
list_add_tail(&p->list, &kvm->ioeventfds);
@@ -760,6 +792,8 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
return 0;
+register_fail:
+ kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
unlock_fail:
mutex_unlock(&kvm->slots_lock);
@@ -799,6 +833,10 @@ kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
continue;
kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
+ if (!p->length) {
+ kvm_io_bus_unregister_dev(kvm, KVM_FAST_MMIO_BUS,
+ &p->dev);
+ }
kvm->buses[bus_idx]->ioeventfd_count--;
ioeventfd_release(p);
ret = 0;
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