[PATCH v8 1/6] kvm: Allow filtering of acked irqs
Registering an kvm_irq_ack_notifier with kian.irq_source_id < 0
retains existing behavior, filling in the actual irq_source_id results
in the callback only being called when the specified irq_source_id is
asserting the given gsi.
The i8254 PIT remains unfiltered because it de-asserts it's irq source
id, so it's notifier would never get called otherwise. KVM device
assignment gets filtering as it de-asserts the GSI in it's notifier.
Signed-off-by: Alex Williamson
---
arch/x86/kvm/i8254.c |1 +
arch/x86/kvm/i8259.c |8 +++-
include/linux/kvm_host.h |4 +++-
virt/kvm/assigned-dev.c |1 +
virt/kvm/ioapic.c|5 -
virt/kvm/irq_comm.c |6 --
6 files changed, 20 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index adba28f..2355d19 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -709,6 +709,7 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
hrtimer_init(&pit_state->pit_timer.timer,
CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
pit_state->irq_ack_notifier.gsi = 0;
+ pit_state->irq_ack_notifier.irq_source_id = -1; /* No filter */
pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
pit_state->pit_timer.reinject = true;
diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
index e498b18..d2175a9 100644
--- a/arch/x86/kvm/i8259.c
+++ b/arch/x86/kvm/i8259.c
@@ -74,9 +74,14 @@ static void pic_unlock(struct kvm_pic *s)
static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
{
+ unsigned long irq_source_ids;
+
s->isr &= ~(1 << irq);
if (s != &s->pics_state->pics[0])
irq += 8;
+
+ irq_source_ids = s->pics_state->irq_states[irq];
+
/*
* We are dropping lock while calling ack notifiers since ack
* notifier callbacks for assigned devices call into PIC recursively.
@@ -84,7 +89,8 @@ static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
* it should be safe since PIC state is already updated at this stage.
*/
pic_unlock(s->pics_state);
- kvm_notify_acked_irq(s->pics_state->kvm, SELECT_PIC(irq), irq);
+ kvm_notify_acked_irq(s->pics_state->kvm, SELECT_PIC(irq), irq,
+irq_source_ids);
pic_lock(s->pics_state);
}
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index b70b48b..2ad3e4a 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -577,6 +577,7 @@ int kvm_is_mmio_pfn(pfn_t pfn);
struct kvm_irq_ack_notifier {
struct hlist_node link;
+ int irq_source_id;
unsigned gsi;
void (*irq_acked)(struct kvm_irq_ack_notifier *kian);
};
@@ -627,7 +628,8 @@ void kvm_get_intr_delivery_bitmask(struct kvm_ioapic
*ioapic,
int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level);
int kvm_set_msi(struct kvm_kernel_irq_routing_entry *irq_entry, struct kvm
*kvm,
int irq_source_id, int level);
-void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin);
+void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin,
+ unsigned long irq_source_ids);
void kvm_register_irq_ack_notifier(struct kvm *kvm,
struct kvm_irq_ack_notifier *kian);
void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
index 23a41a9..a08c9c1 100644
--- a/virt/kvm/assigned-dev.c
+++ b/virt/kvm/assigned-dev.c
@@ -407,6 +407,7 @@ static int assigned_device_enable_guest_intx(struct kvm
*kvm,
{
dev->guest_irq = irq->guest_irq;
dev->ack_notifier.gsi = irq->guest_irq;
+ dev->ack_notifier.irq_source_id = dev->irq_source_id;
return 0;
}
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index ef61d52..1a9f445 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -241,10 +241,12 @@ static void __kvm_ioapic_update_eoi(struct kvm_ioapic
*ioapic, int vector,
for (i = 0; i < IOAPIC_NUM_PINS; i++) {
union kvm_ioapic_redirect_entry *ent = &ioapic->redirtbl[i];
+ unsigned long irq_source_ids;
if (ent->fields.vector != vector)
continue;
+ irq_source_ids = ioapic->irq_states[i];
/*
* We are dropping lock while calling ack notifiers because ack
* notifier callbacks for assigned devices call into IOAPIC
@@ -254,7 +256,8 @@ static void __kvm_ioapic_update_eoi(struct kvm_ioapic
*ioapic, int vector,
* after ack notifier returns.
*/
spin_unlock(&ioapic->lock);
- kvm_notify_acked_irq(ioapic->kvm, KVM_IRQCHIP_IOAPIC, i);
+ kvm_notify_acked_irq(ioapic->kvm, KVM_IRQCHIP_IOAPIC, i,
+
Re: [PATCH v8 1/6] kvm: Allow filtering of acked irqs
On Fri, Aug 10, 2012 at 04:37:17PM -0600, Alex Williamson wrote:
> Registering an kvm_irq_ack_notifier with kian.irq_source_id < 0
> retains existing behavior, filling in the actual irq_source_id results
> in the callback only being called when the specified irq_source_id is
> asserting the given gsi.
>
> The i8254 PIT remains unfiltered because it de-asserts it's irq source
> id, so it's notifier would never get called otherwise. KVM device
> assignment gets filtering as it de-asserts the GSI in it's notifier.
>
> Signed-off-by: Alex Williamson
Looks good to me. For the record, I expect this to help if
- an assigned device interrupt is shared in host
so we use slow config cycles in the ack notifier
- said device is sharing interrupt with another device in guest
- said another device is actually driving most interrupts
For example, I think this could be tested
by booting guest with pci=nomsi.
A minor suggestions below but
nothing that needs to block this patch.
> ---
>
> arch/x86/kvm/i8254.c |1 +
> arch/x86/kvm/i8259.c |8 +++-
> include/linux/kvm_host.h |4 +++-
> virt/kvm/assigned-dev.c |1 +
> virt/kvm/ioapic.c|5 -
> virt/kvm/irq_comm.c |6 --
> 6 files changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
> index adba28f..2355d19 100644
> --- a/arch/x86/kvm/i8254.c
> +++ b/arch/x86/kvm/i8254.c
> @@ -709,6 +709,7 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
> hrtimer_init(&pit_state->pit_timer.timer,
>CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
> pit_state->irq_ack_notifier.gsi = 0;
> + pit_state->irq_ack_notifier.irq_source_id = -1; /* No filter */
A bit prettier would be to
#define KVM_NO_IRQ_SOURCE_ID (-1)
and test for it explicitly.
> pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
> kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
> pit_state->pit_timer.reinject = true;
> diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
> index e498b18..d2175a9 100644
> --- a/arch/x86/kvm/i8259.c
> +++ b/arch/x86/kvm/i8259.c
> @@ -74,9 +74,14 @@ static void pic_unlock(struct kvm_pic *s)
>
> static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
> {
> + unsigned long irq_source_ids;
> +
> s->isr &= ~(1 << irq);
> if (s != &s->pics_state->pics[0])
> irq += 8;
> +
> + irq_source_ids = s->pics_state->irq_states[irq];
> +
> /*
>* We are dropping lock while calling ack notifiers since ack
>* notifier callbacks for assigned devices call into PIC recursively.
> @@ -84,7 +89,8 @@ static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
>* it should be safe since PIC state is already updated at this stage.
>*/
> pic_unlock(s->pics_state);
> - kvm_notify_acked_irq(s->pics_state->kvm, SELECT_PIC(irq), irq);
> + kvm_notify_acked_irq(s->pics_state->kvm, SELECT_PIC(irq), irq,
> + irq_source_ids);
> pic_lock(s->pics_state);
> }
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index b70b48b..2ad3e4a 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -577,6 +577,7 @@ int kvm_is_mmio_pfn(pfn_t pfn);
>
> struct kvm_irq_ack_notifier {
> struct hlist_node link;
> + int irq_source_id;
> unsigned gsi;
> void (*irq_acked)(struct kvm_irq_ack_notifier *kian);
> };
> @@ -627,7 +628,8 @@ void kvm_get_intr_delivery_bitmask(struct kvm_ioapic
> *ioapic,
> int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level);
> int kvm_set_msi(struct kvm_kernel_irq_routing_entry *irq_entry, struct kvm
> *kvm,
> int irq_source_id, int level);
> -void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin);
> +void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin,
> + unsigned long irq_source_ids);
> void kvm_register_irq_ack_notifier(struct kvm *kvm,
> struct kvm_irq_ack_notifier *kian);
> void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
> diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
> index 23a41a9..a08c9c1 100644
> --- a/virt/kvm/assigned-dev.c
> +++ b/virt/kvm/assigned-dev.c
> @@ -407,6 +407,7 @@ static int assigned_device_enable_guest_intx(struct kvm
> *kvm,
> {
> dev->guest_irq = irq->guest_irq;
> dev->ack_notifier.gsi = irq->guest_irq;
> + dev->ack_notifier.irq_source_id = dev->irq_source_id;
> return 0;
> }
>
> diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
> index ef61d52..1a9f445 100644
> --- a/virt/kvm/ioapic.c
> +++ b/virt/kvm/ioapic.c
> @@ -241,10 +241,12 @@ static void __kvm_ioapic_update_eoi(struct kvm_ioapic
> *ioapic, int vector,
>
> for (i = 0; i < IOAPIC_NUM_PINS; i++) {
> union kvm_ioapic_redirect_entry *ent = &ioapic->r
Re: [PATCH v8 1/6] kvm: Allow filtering of acked irqs
On Wed, 2012-08-15 at 15:27 +0300, Michael S. Tsirkin wrote:
> On Fri, Aug 10, 2012 at 04:37:17PM -0600, Alex Williamson wrote:
> > Registering an kvm_irq_ack_notifier with kian.irq_source_id < 0
> > retains existing behavior, filling in the actual irq_source_id results
> > in the callback only being called when the specified irq_source_id is
> > asserting the given gsi.
> >
> > The i8254 PIT remains unfiltered because it de-asserts it's irq source
> > id, so it's notifier would never get called otherwise. KVM device
> > assignment gets filtering as it de-asserts the GSI in it's notifier.
> >
> > Signed-off-by: Alex Williamson
>
> Looks good to me. For the record, I expect this to help if
> - an assigned device interrupt is shared in host
> so we use slow config cycles in the ack notifier
> - said device is sharing interrupt with another device in guest
> - said another device is actually driving most interrupts
> For example, I think this could be tested
> by booting guest with pci=nomsi.
Yes, that's how I do most of my testing of legacy interrupts with
vfio-pci. KVM assignment is smart enough not to do config access unless
the irq is marked as disabled, but it does eliminate an unnecessary
de-assert and a couple spinlocks in assignment code.
> A minor suggestions below but
> nothing that needs to block this patch.
>
> > ---
> >
> > arch/x86/kvm/i8254.c |1 +
> > arch/x86/kvm/i8259.c |8 +++-
> > include/linux/kvm_host.h |4 +++-
> > virt/kvm/assigned-dev.c |1 +
> > virt/kvm/ioapic.c|5 -
> > virt/kvm/irq_comm.c |6 --
> > 6 files changed, 20 insertions(+), 5 deletions(-)
> >
> > diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
> > index adba28f..2355d19 100644
> > --- a/arch/x86/kvm/i8254.c
> > +++ b/arch/x86/kvm/i8254.c
> > @@ -709,6 +709,7 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32
> > flags)
> > hrtimer_init(&pit_state->pit_timer.timer,
> > CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
> > pit_state->irq_ack_notifier.gsi = 0;
> > + pit_state->irq_ack_notifier.irq_source_id = -1; /* No filter */
>
> A bit prettier would be to
> #define KVM_NO_IRQ_SOURCE_ID (-1)
> and test for it explicitly.
Ok. I'll add a define and resend this one. Thanks,
Alex
> > pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
> > kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
> > pit_state->pit_timer.reinject = true;
> > diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
> > index e498b18..d2175a9 100644
> > --- a/arch/x86/kvm/i8259.c
> > +++ b/arch/x86/kvm/i8259.c
> > @@ -74,9 +74,14 @@ static void pic_unlock(struct kvm_pic *s)
> >
> > static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
> > {
> > + unsigned long irq_source_ids;
> > +
> > s->isr &= ~(1 << irq);
> > if (s != &s->pics_state->pics[0])
> > irq += 8;
> > +
> > + irq_source_ids = s->pics_state->irq_states[irq];
> > +
> > /*
> > * We are dropping lock while calling ack notifiers since ack
> > * notifier callbacks for assigned devices call into PIC recursively.
> > @@ -84,7 +89,8 @@ static void pic_clear_isr(struct kvm_kpic_state *s, int
> > irq)
> > * it should be safe since PIC state is already updated at this stage.
> > */
> > pic_unlock(s->pics_state);
> > - kvm_notify_acked_irq(s->pics_state->kvm, SELECT_PIC(irq), irq);
> > + kvm_notify_acked_irq(s->pics_state->kvm, SELECT_PIC(irq), irq,
> > +irq_source_ids);
> > pic_lock(s->pics_state);
> > }
> >
> > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> > index b70b48b..2ad3e4a 100644
> > --- a/include/linux/kvm_host.h
> > +++ b/include/linux/kvm_host.h
> > @@ -577,6 +577,7 @@ int kvm_is_mmio_pfn(pfn_t pfn);
> >
> > struct kvm_irq_ack_notifier {
> > struct hlist_node link;
> > + int irq_source_id;
> > unsigned gsi;
> > void (*irq_acked)(struct kvm_irq_ack_notifier *kian);
> > };
> > @@ -627,7 +628,8 @@ void kvm_get_intr_delivery_bitmask(struct kvm_ioapic
> > *ioapic,
> > int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level);
> > int kvm_set_msi(struct kvm_kernel_irq_routing_entry *irq_entry, struct kvm
> > *kvm,
> > int irq_source_id, int level);
> > -void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin);
> > +void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin,
> > + unsigned long irq_source_ids);
> > void kvm_register_irq_ack_notifier(struct kvm *kvm,
> >struct kvm_irq_ack_notifier *kian);
> > void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
> > diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
> > index 23a41a9..a08c9c1 100644
> > --- a/virt/kvm/assigned-dev.c
> > +++ b/virt/kvm/assigned-dev.c
> > @@ -407,6 +407,7 @@ static int assigned_device_enable_guest_intx(struct kvm
>
Re: [PATCH v8 1/6] kvm: Allow filtering of acked irqs
On Wed, Aug 15, 2012 at 10:47:38AM -0600, Alex Williamson wrote:
> On Wed, 2012-08-15 at 15:27 +0300, Michael S. Tsirkin wrote:
> > On Fri, Aug 10, 2012 at 04:37:17PM -0600, Alex Williamson wrote:
> > > Registering an kvm_irq_ack_notifier with kian.irq_source_id < 0
> > > retains existing behavior, filling in the actual irq_source_id results
> > > in the callback only being called when the specified irq_source_id is
> > > asserting the given gsi.
> > >
> > > The i8254 PIT remains unfiltered because it de-asserts it's irq source
> > > id, so it's notifier would never get called otherwise. KVM device
> > > assignment gets filtering as it de-asserts the GSI in it's notifier.
> > >
> > > Signed-off-by: Alex Williamson
> >
> > Looks good to me. For the record, I expect this to help if
> > - an assigned device interrupt is shared in host
> > so we use slow config cycles in the ack notifier
> > - said device is sharing interrupt with another device in guest
> > - said another device is actually driving most interrupts
> > For example, I think this could be tested
> > by booting guest with pci=nomsi.
>
> Yes, that's how I do most of my testing of legacy interrupts with
> vfio-pci. KVM assignment is smart enough not to do config access unless
> the irq is marked as disabled, but it does eliminate an unnecessary
> de-assert and a couple spinlocks in assignment code.
Hmm this is less than I thought. Any performance numbers?
> > A minor suggestions below but
> > nothing that needs to block this patch.
> >
> > > ---
> > >
> > > arch/x86/kvm/i8254.c |1 +
> > > arch/x86/kvm/i8259.c |8 +++-
> > > include/linux/kvm_host.h |4 +++-
> > > virt/kvm/assigned-dev.c |1 +
> > > virt/kvm/ioapic.c|5 -
> > > virt/kvm/irq_comm.c |6 --
> > > 6 files changed, 20 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
> > > index adba28f..2355d19 100644
> > > --- a/arch/x86/kvm/i8254.c
> > > +++ b/arch/x86/kvm/i8254.c
> > > @@ -709,6 +709,7 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32
> > > flags)
> > > hrtimer_init(&pit_state->pit_timer.timer,
> > >CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
> > > pit_state->irq_ack_notifier.gsi = 0;
> > > + pit_state->irq_ack_notifier.irq_source_id = -1; /* No filter */
> >
> > A bit prettier would be to
> > #define KVM_NO_IRQ_SOURCE_ID (-1)
> > and test for it explicitly.
>
> Ok. I'll add a define and resend this one. Thanks,
>
> Alex
>
> > > pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
> > > kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
> > > pit_state->pit_timer.reinject = true;
> > > diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
> > > index e498b18..d2175a9 100644
> > > --- a/arch/x86/kvm/i8259.c
> > > +++ b/arch/x86/kvm/i8259.c
> > > @@ -74,9 +74,14 @@ static void pic_unlock(struct kvm_pic *s)
> > >
> > > static void pic_clear_isr(struct kvm_kpic_state *s, int irq)
> > > {
> > > + unsigned long irq_source_ids;
> > > +
> > > s->isr &= ~(1 << irq);
> > > if (s != &s->pics_state->pics[0])
> > > irq += 8;
> > > +
> > > + irq_source_ids = s->pics_state->irq_states[irq];
> > > +
> > > /*
> > >* We are dropping lock while calling ack notifiers since ack
> > >* notifier callbacks for assigned devices call into PIC recursively.
> > > @@ -84,7 +89,8 @@ static void pic_clear_isr(struct kvm_kpic_state *s, int
> > > irq)
> > >* it should be safe since PIC state is already updated at this stage.
> > >*/
> > > pic_unlock(s->pics_state);
> > > - kvm_notify_acked_irq(s->pics_state->kvm, SELECT_PIC(irq), irq);
> > > + kvm_notify_acked_irq(s->pics_state->kvm, SELECT_PIC(irq), irq,
> > > + irq_source_ids);
> > > pic_lock(s->pics_state);
> > > }
> > >
> > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> > > index b70b48b..2ad3e4a 100644
> > > --- a/include/linux/kvm_host.h
> > > +++ b/include/linux/kvm_host.h
> > > @@ -577,6 +577,7 @@ int kvm_is_mmio_pfn(pfn_t pfn);
> > >
> > > struct kvm_irq_ack_notifier {
> > > struct hlist_node link;
> > > + int irq_source_id;
> > > unsigned gsi;
> > > void (*irq_acked)(struct kvm_irq_ack_notifier *kian);
> > > };
> > > @@ -627,7 +628,8 @@ void kvm_get_intr_delivery_bitmask(struct kvm_ioapic
> > > *ioapic,
> > > int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level);
> > > int kvm_set_msi(struct kvm_kernel_irq_routing_entry *irq_entry, struct
> > > kvm *kvm,
> > > int irq_source_id, int level);
> > > -void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned
> > > pin);
> > > +void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned
> > > pin,
> > > + unsigned long irq_source_ids);
> > > void kvm_register_irq_ack_notifier(struct kvm *kvm,
> > > struct kvm_irq_ack_notifier *kian);
> >
