Il 05/05/2014 16:21, Christian Borntraeger ha scritto:
On 28/04/14 18:39, Paolo Bonzini wrote:
From: Christian Borntraeger <[email protected]>
Given all your work, What about From: Paolo Bonzini <[email protected]>
plus "Based on an inital patch from Christian Borntraeger"
No big deal, I don't care about authorship that much.
@@ -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);
No idea what resampler is, can this become time critical as well - iow do we
need expedited here?
It's for level-triggered interrupts. I decided that if synchronize_rcu
was good enough before, synchronize_srcu will do after the patch.
@@ -85,7 +86,7 @@ void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
mutex_lock(&kvm->irq_lock);
hlist_del_init_rcu(&kian->link);
mutex_unlock(&kvm->irq_lock);
- synchronize_rcu();
+ synchronize_srcu_expedited(&kvm->irq_srcu);
Hmm, looks like all callers are slow path (shutdown, deregister assigned dev).
Couldnt
we use the non expedited variant?
... but I have screwed up this one. Thanks, I'll change it.
r = kvm_arch_init_vm(kvm, type);
if (r)
- goto out_err_nodisable;
+ goto out_err_no_disable;
r = hardware_enable_all();
if (r)
- goto out_err_nodisable;
+ goto out_err_no_disable;
#ifdef CONFIG_HAVE_KVM_IRQCHIP
INIT_HLIST_HEAD(&kvm->mask_notifier_list);
@@ -473,10 +473,12 @@ static struct kvm *kvm_create_vm(unsigned long type)
r = -ENOMEM;
kvm->memslots = kzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);
if (!kvm->memslots)
- goto out_err_nosrcu;
+ goto out_err_no_srcu;
kvm_init_memslots_id(kvm);
if (init_srcu_struct(&kvm->srcu))
- goto out_err_nosrcu;
+ goto out_err_no_srcu;
+ if (init_srcu_struct(&kvm->irq_srcu))
+ goto out_err_no_irq_srcu;
for (i = 0; i < KVM_NR_BUSES; i++) {
kvm->buses[i] = kzalloc(sizeof(struct kvm_io_bus),
GFP_KERNEL);
@@ -505,10 +507,12 @@ static struct kvm *kvm_create_vm(unsigned long type)
return kvm;
out_err:
+ cleanup_srcu_struct(&kvm->irq_srcu);
+out_err_no_irq_srcu:
cleanup_srcu_struct(&kvm->srcu);
-out_err_nosrcu:
+out_err_no_srcu:
hardware_disable_all();
-out_err_nodisable:
+out_err_no_disable:
the patch would be smaller without this change, but it makes the naming more
consistent, so ok.
Yeah, out_err_noirq_srcu or out_err_noirqsrcu are both very ugly.
Thanks for the review, I'm making the small change to remove expedited
and applying to kvm/queue.
Paolo
for (i = 0; i < KVM_NR_BUSES; i++)
kfree(kvm->buses[i]);
kfree(kvm->memslots);
--
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