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authorGleb Natapov <gleb@redhat.com>2009-08-24 11:54:26 +0300
committerAvi Kivity <avi@redhat.com>2009-12-03 09:32:08 +0200
commit680b3648ba89c44ac8d0316f78a0d6e147b88809 (patch)
treeb2b40034c4c33affef8b89822673cca835874651 /virt
parenteba0226bdfffe262e72b8360e4d0d12070e9a0f0 (diff)
downloadlinux-2.6.34-ux500-680b3648ba89c44ac8d0316f78a0d6e147b88809.tar.gz
KVM: Drop kvm->irq_lock lock from irq injection path
The only thing it protects now is interrupt injection into lapic and this can work lockless. Even now with kvm->irq_lock in place access to lapic is not entirely serialized since vcpu access doesn't take kvm->irq_lock. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/eventfd.c2
-rw-r--r--virt/kvm/irq_comm.c6
-rw-r--r--virt/kvm/kvm_main.c2
3 files changed, 1 insertions, 9 deletions
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index bb4ebd89b9f..30f70fd511c 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -61,10 +61,8 @@ irqfd_inject(struct work_struct *work)
struct _irqfd *irqfd = container_of(work, struct _irqfd, inject);
struct kvm *kvm = irqfd->kvm;
- mutex_lock(&kvm->irq_lock);
kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1);
kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0);
- mutex_unlock(&kvm->irq_lock);
}
/*
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index fadf4408a82..15a83b93566 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -82,8 +82,6 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
int i, r = -1;
struct kvm_vcpu *vcpu, *lowest = NULL;
- WARN_ON(!mutex_is_locked(&kvm->irq_lock));
-
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");
@@ -138,7 +136,7 @@ static int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
return kvm_irq_delivery_to_apic(kvm, NULL, &irq);
}
-/* This should be called with the kvm->irq_lock mutex held
+/*
* Return value:
* < 0 Interrupt was ignored (masked or not delivered for other reasons)
* = 0 Interrupt was coalesced (previous irq is still pending)
@@ -153,8 +151,6 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level)
trace_kvm_set_irq(irq, level, irq_source_id);
- WARN_ON(!mutex_is_locked(&kvm->irq_lock));
-
/* 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.
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 6eca153e1a0..c12c95b1b64 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -137,7 +137,6 @@ static void kvm_assigned_dev_interrupt_work_handler(struct work_struct *work)
interrupt_work);
kvm = assigned_dev->kvm;
- mutex_lock(&kvm->irq_lock);
spin_lock_irq(&assigned_dev->assigned_dev_lock);
if (assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSIX) {
struct kvm_guest_msix_entry *guest_entries =
@@ -156,7 +155,6 @@ static void kvm_assigned_dev_interrupt_work_handler(struct work_struct *work)
assigned_dev->guest_irq, 1);
spin_unlock_irq(&assigned_dev->assigned_dev_lock);
- mutex_unlock(&assigned_dev->kvm->irq_lock);
}
static irqreturn_t kvm_assigned_dev_intr(int irq, void *dev_id)