[PATCH 09/10] Drop kvm->irq_lock lock.
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
---
arch/ia64/kvm/kvm-ia64.c |2 --
arch/x86/kvm/i8254.c |2 --
arch/x86/kvm/lapic.c |2 --
arch/x86/kvm/x86.c |2 --
include/linux/kvm_host.h |1 -
virt/kvm/eventfd.c |2 --
virt/kvm/irq_comm.c |6 +-
virt/kvm/kvm_main.c |5 +
8 files changed, 2 insertions(+), 20 deletions(-)
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index dd7ef2d..8f1fc3a 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -998,10 +998,8 @@ long kvm_arch_vm_ioctl(struct file *filp,
goto out;
if (irqchip_in_kernel(kvm)) {
__s32 status;
- mutex_lock(&kvm->irq_lock);
status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
irq_event.irq, irq_event.level);
- mutex_unlock(&kvm->irq_lock);
if (ioctl == KVM_IRQ_LINE_STATUS) {
irq_event.status = status;
if (copy_to_user(argp, &irq_event,
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 1330b2a..f3d3382 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -690,10 +690,8 @@ static void __inject_pit_timer_intr(struct kvm *kvm)
struct kvm_vcpu *vcpu;
int i;
- mutex_lock(&kvm->irq_lock);
kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1);
kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0);
- mutex_unlock(&kvm->irq_lock);
/*
* Provides NMI watchdog support via Virtual Wire mode.
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index f24d4d0..e41e948 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -501,9 +501,7 @@ static void apic_send_ipi(struct kvm_lapic *apic)
irq.trig_mode, irq.level, irq.dest_mode, irq.delivery_mode,
irq.vector);
- mutex_lock(&apic->vcpu->kvm->irq_lock);
kvm_irq_delivery_to_apic(apic->vcpu->kvm, apic, &irq);
- mutex_unlock(&apic->vcpu->kvm->irq_lock);
}
static u32 apic_get_tmcct(struct kvm_lapic *apic)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1ac1695..d313462 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2284,10 +2284,8 @@ long kvm_arch_vm_ioctl(struct file *filp,
goto out;
if (irqchip_in_kernel(kvm)) {
__s32 status;
- mutex_lock(&kvm->irq_lock);
status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
irq_event.irq, irq_event.level);
- mutex_unlock(&kvm->irq_lock);
if (ioctl == KVM_IRQ_LINE_STATUS) {
irq_event.status = status;
if (copy_to_user(argp, &irq_event,
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 3610661..b3db9bf 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -172,7 +172,6 @@ struct kvm {
struct kvm_coalesced_mmio_ring *coalesced_mmio_ring;
#endif
- struct mutex irq_lock;
#ifdef CONFIG_HAVE_KVM_IRQCHIP
struct kvm_irq_routing_table *irq_routing;
spinlock_t irq_routing_lock;
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 99017e8..95954ad 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 43ace95..dd9a5ca 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -65,8 +65,6 @@ 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");
@@ -118,7 +116,7 @@ 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 re
[PATCH 09/10] Drop kvm->irq_lock lock.
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
---
arch/ia64/kvm/kvm-ia64.c |2 --
arch/x86/kvm/i8254.c |2 --
arch/x86/kvm/lapic.c |2 --
arch/x86/kvm/x86.c |2 --
include/linux/kvm_host.h |1 -
virt/kvm/eventfd.c |2 --
virt/kvm/irq_comm.c |6 +-
virt/kvm/kvm_main.c |5 +
8 files changed, 2 insertions(+), 20 deletions(-)
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index dd7ef2d..8f1fc3a 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -998,10 +998,8 @@ long kvm_arch_vm_ioctl(struct file *filp,
goto out;
if (irqchip_in_kernel(kvm)) {
__s32 status;
- mutex_lock(&kvm->irq_lock);
status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
irq_event.irq, irq_event.level);
- mutex_unlock(&kvm->irq_lock);
if (ioctl == KVM_IRQ_LINE_STATUS) {
irq_event.status = status;
if (copy_to_user(argp, &irq_event,
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 59021da..211f524 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -690,10 +690,8 @@ static void __inject_pit_timer_intr(struct kvm *kvm)
struct kvm_vcpu *vcpu;
int i;
- mutex_lock(&kvm->irq_lock);
kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1);
kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0);
- mutex_unlock(&kvm->irq_lock);
/*
* Provides NMI watchdog support via Virtual Wire mode.
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 61ffcfc..0380107 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -501,9 +501,7 @@ static void apic_send_ipi(struct kvm_lapic *apic)
irq.trig_mode, irq.level, irq.dest_mode, irq.delivery_mode,
irq.vector);
- mutex_lock(&apic->vcpu->kvm->irq_lock);
kvm_irq_delivery_to_apic(apic->vcpu->kvm, apic, &irq);
- mutex_unlock(&apic->vcpu->kvm->irq_lock);
}
static u32 apic_get_tmcct(struct kvm_lapic *apic)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index de99b84..40adac5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2261,10 +2261,8 @@ long kvm_arch_vm_ioctl(struct file *filp,
goto out;
if (irqchip_in_kernel(kvm)) {
__s32 status;
- mutex_lock(&kvm->irq_lock);
status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
irq_event.irq, irq_event.level);
- mutex_unlock(&kvm->irq_lock);
if (ioctl == KVM_IRQ_LINE_STATUS) {
irq_event.status = status;
if (copy_to_user(argp, &irq_event,
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 4eb5c85..aa64d0d 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -164,7 +164,6 @@ struct kvm {
struct kvm_coalesced_mmio_ring *coalesced_mmio_ring;
#endif
- struct mutex irq_lock;
#ifdef CONFIG_HAVE_KVM_IRQCHIP
struct kvm_kernel_irq_routing_entry *irq_routing;
spinlock_t irq_routing_lock;
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 99017e8..95954ad 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 59c1cde..c54a28b 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -63,8 +63,6 @@ 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");
@@ -116,7 +114,7 @@ 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 o
