On Mon, Oct 17, 2011 at 02:07:41PM -0200, Marcelo Tosatti wrote:
> > > Configurations to consider, all common ones used for assigned devices?
> >
> > I mean, besides round robin, any other modes that
> > have an issue? Interrupts can also be multicast,
> > I think, but we probably don't care what happens
> > to affinity then, as msi interrupts are probably never
> > broadcast ...
>
> There is also lowest priority, which can be used with MSI.
So the following will probably address that comment?
diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
index f89f138..b579777 100644
--- a/virt/kvm/assigned-dev.c
+++ b/virt/kvm/assigned-dev.c
@@ -142,9 +142,11 @@ static void deassign_host_irq(struct kvm *kvm,
for (i = 0; i < assigned_dev->entries_nr; i++)
disable_irq(assigned_dev->host_msix_entries[i].vector);
- for (i = 0; i < assigned_dev->entries_nr; i++)
- free_irq(assigned_dev->host_msix_entries[i].vector,
- (void *)assigned_dev);
+ for (i = 0; i < assigned_dev->entries_nr; i++) {
+ u32 vector = assigned_dev->host_msix_entries[i].vector;
+ irq_set_affinity_hint(vector, NULL);
+ free_irq(vector, (void *)assigned_dev);
+ }
assigned_dev->entries_nr = 0;
kfree(assigned_dev->host_msix_entries);
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index ac8b629..dabf89f 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -22,6 +22,7 @@
#include <linux/kvm_host.h>
#include <linux/slab.h>
+#include <linux/interrupt.h>
#include <trace/events/kvm.h>
#include <asm/msidef.h>
@@ -80,11 +81,23 @@ inline static bool kvm_is_dm_lowest_prio(struct
kvm_lapic_irq *irq)
#endif
}
+static void kvm_vcpu_host_irq_hint(struct kvm_vcpu *vcpu, int host_irq)
+{
+ const struct cpumask *mask;
+ /* raw_smp_processor_id() is ok here: if we get preempted we can get a
+ * wrong value but we don't mind much. */
+ if (host_irq >= 0 && unlikely(vcpu->cpu != raw_smp_processor_id())) {
+ mask = get_cpu_mask(vcpu->cpu);
+ irq_set_affinity_hint(host_irq, mask);
+ }
+}
+
int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
struct kvm_lapic_irq *irq, int host_irq)
{
int i, r = -1;
- struct kvm_vcpu *vcpu, *lowest = NULL;
+ int matches = 0;
+ struct kvm_vcpu *vcpu, *lowest = NULL, *match;
if (irq->dest_mode == 0 && irq->dest_id == 0xff &&
kvm_is_dm_lowest_prio(irq))
@@ -98,10 +111,13 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct
kvm_lapic *src,
irq->dest_id, irq->dest_mode))
continue;
+ ++matches;
+
if (!kvm_is_dm_lowest_prio(irq)) {
if (r < 0)
r = 0;
r += kvm_apic_set_irq(vcpu, irq);
+ match = vcpu;
} else if (kvm_lapic_enabled(vcpu)) {
if (!lowest)
lowest = vcpu;
@@ -110,8 +126,13 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct
kvm_lapic *src,
}
}
- if (lowest)
+ if (lowest) {
r = kvm_apic_set_irq(lowest, irq);
+ match = lowest;
+ }
+
+ if (matches == 1)
+ kvm_vcpu_host_irq_hint(match, host_irq);
return r;
}
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