Essentially nothing is changed from my previous patch.
Diffs are:
- split hvm_dirq_assist() for readability
- a little bit efficent for MP race condition
The attached patch is not so readable.
I'll show the following handmade diff for human.
=======================================================================
void hvm_dirq_assist(struct vcpu *v)
{
struct domain *d = v->domain;
struct hvm_irq_dpci *hvm_irq_dpci = d->arch.hvm_domain.irq.dpci;
- unsigned int irq;
+ unsigned int irq, i, dirq_mask_size;
+ unsigned long mask;
- if ( !iommu_enabled || (v->vcpu_id != 0) || (hvm_irq_dpci == NULL) )
+ if ( !iommu_enabled || (hvm_irq_dpci == NULL) )
return;
- for ( irq = find_first_bit(hvm_irq_dpci->dirq_mask, d->nr_pirqs);
- irq < d->nr_pirqs;
- irq = find_next_bit(hvm_irq_dpci->dirq_mask, d->nr_pirqs, irq + 1) )
- {
- if ( !test_and_clear_bit(irq, hvm_irq_dpci->dirq_mask) )
- continue;
-
- __hvm_dirq_assist(d, hvm_irq_dpci, irq);
- }
+ dirq_mask_size = BITS_TO_LONGS(d->nr_pirqs);
+ for (i = 0; i < dirq_mask_size; i++)
+ mask = xchg(&hvm_irq_dpci->dirq_mask[i], 0L);
+
+ while ( mask != 0 )
+ {
+ irq = find_first_set_bit(mask);
+ mask &= ~(1UL << irq);
+ irq += (i * BITS_PER_LONG);
+ if ( irq < d->nr_pirqs )
+ __hvm_dirq_assist(d, hvm_irq_dpci, irq);
+ }
+ }
}
=======================================================================
while d->nr_pirqs<=64, dirq_mask_size is 1 (d->nr_pirqs is normally 32).
Then the efficiency is not so worse than comparing v->vcpu_id != 0.
Thanks,
Kouya
# HG changeset patch
# User Kouya Shimura <kouya@xxxxxxxxxxxxxx>
# Date 1247204881 -32400
# Node ID 7b1506cac37df608120ec665cef3dd3bb1ddc94a
# Parent 20743a0a4ac5c9969beebd7bd414ace7de030cfd
passthrough: deliver IRQs even if VCPU#0 is halted
Signed-off-by: Kouya Shimura <kouya@xxxxxxxxxxxxxx>
diff -r 20743a0a4ac5 -r 7b1506cac37d xen/drivers/passthrough/io.c
--- a/xen/drivers/passthrough/io.c Thu Jul 09 17:06:40 2009 +0100
+++ b/xen/drivers/passthrough/io.c Fri Jul 10 14:48:01 2009 +0900
@@ -362,6 +362,7 @@ int hvm_do_IRQ_dpci(struct domain *d, un
int hvm_do_IRQ_dpci(struct domain *d, unsigned int mirq)
{
struct hvm_irq_dpci *dpci = domain_get_irq_dpci(d);
+ struct vcpu *v;
ASSERT(spin_is_locked(&irq_desc[domain_irq_to_vector(d, mirq)].lock));
if ( !iommu_enabled || (d == dom0) || !dpci ||
@@ -378,7 +379,14 @@ int hvm_do_IRQ_dpci(struct domain *d, un
if ( pt_irq_need_timer(dpci->mirq[mirq].flags) )
set_timer(&dpci->hvm_timer[domain_irq_to_vector(d, mirq)],
NOW() + PT_IRQ_TIME_OUT);
- vcpu_kick(d->vcpu[0]);
+
+ /* Kick an online VCPU. mostly VCPU#0 except kdump case. */
+ for_each_vcpu(d, v)
+ if ( !test_bit(_VPF_down, &v->pause_flags) )
+ {
+ vcpu_kick(v);
+ break;
+ }
return 1;
}
@@ -429,63 +437,76 @@ static int hvm_pci_msi_assert(struct dom
}
#endif
+static void __hvm_dirq_assist(
+ struct domain *d, struct hvm_irq_dpci *hvm_irq_dpci, unsigned int irq)
+{
+ uint32_t device, intx;
+ struct dev_intx_gsi_link *digl;
+
+ spin_lock(&d->event_lock);
+#ifdef SUPPORT_MSI_REMAPPING
+ if ( hvm_irq_dpci->mirq[irq].flags & HVM_IRQ_DPCI_GUEST_MSI )
+ {
+ hvm_pci_msi_assert(d, irq);
+ spin_unlock(&d->event_lock);
+ return;
+ }
+#endif
+ if ( pt_irq_need_timer(hvm_irq_dpci->mirq[irq].flags) )
+ stop_timer(&hvm_irq_dpci->hvm_timer[domain_irq_to_vector(d, irq)]);
+
+ list_for_each_entry ( digl, &hvm_irq_dpci->mirq[irq].digl_list, list )
+ {
+ device = digl->device;
+ intx = digl->intx;
+ hvm_pci_intx_assert(d, device, intx);
+ hvm_irq_dpci->mirq[irq].pending++;
+
+#ifdef SUPPORT_MSI_REMAPPING
+ if ( hvm_irq_dpci->mirq[irq].flags & HVM_IRQ_DPCI_TRANSLATE )
+ {
+ /* for translated MSI to INTx, eoi as early as possible */
+ __msi_pirq_eoi(d, irq);
+ }
+#endif
+ }
+
+ /*
+ * Set a timer to see if the guest can finish the interrupt or not. For
+ * example, the guest OS may unmask the PIC during boot, before the
+ * guest driver is loaded. hvm_pci_intx_assert() may succeed, but the
+ * guest will never deal with the irq, then the physical interrupt line
+ * will never be deasserted.
+ */
+ if ( pt_irq_need_timer(hvm_irq_dpci->mirq[irq].flags) )
+ set_timer(&hvm_irq_dpci->hvm_timer[domain_irq_to_vector(d, irq)],
+ NOW() + PT_IRQ_TIME_OUT);
+ spin_unlock(&d->event_lock);
+}
+
void hvm_dirq_assist(struct vcpu *v)
{
- unsigned int irq;
- uint32_t device, intx;
struct domain *d = v->domain;
struct hvm_irq_dpci *hvm_irq_dpci = d->arch.hvm_domain.irq.dpci;
- struct dev_intx_gsi_link *digl;
+ unsigned int irq, i, dirq_mask_size;
+ unsigned long mask;
- if ( !iommu_enabled || (v->vcpu_id != 0) || (hvm_irq_dpci == NULL) )
+ if ( !iommu_enabled || (hvm_irq_dpci == NULL) )
return;
- for ( irq = find_first_bit(hvm_irq_dpci->dirq_mask, d->nr_pirqs);
- irq < d->nr_pirqs;
- irq = find_next_bit(hvm_irq_dpci->dirq_mask, d->nr_pirqs, irq + 1) )
+ dirq_mask_size = BITS_TO_LONGS(d->nr_pirqs);
+ for (i = 0; i < dirq_mask_size; i++)
{
- if ( !test_and_clear_bit(irq, hvm_irq_dpci->dirq_mask) )
- continue;
+ mask = xchg(&hvm_irq_dpci->dirq_mask[i], 0L);
- spin_lock(&d->event_lock);
-#ifdef SUPPORT_MSI_REMAPPING
- if ( hvm_irq_dpci->mirq[irq].flags & HVM_IRQ_DPCI_GUEST_MSI )
+ while ( mask != 0 )
{
- hvm_pci_msi_assert(d, irq);
- spin_unlock(&d->event_lock);
- continue;
+ irq = find_first_set_bit(mask);
+ mask &= ~(1UL << irq);
+ irq += (i * BITS_PER_LONG);
+ if ( irq < d->nr_pirqs )
+ __hvm_dirq_assist(d, hvm_irq_dpci, irq);
}
-#endif
- if ( pt_irq_need_timer(hvm_irq_dpci->mirq[irq].flags) )
- stop_timer(&hvm_irq_dpci->hvm_timer[domain_irq_to_vector(d, irq)]);
-
- list_for_each_entry ( digl, &hvm_irq_dpci->mirq[irq].digl_list, list )
- {
- device = digl->device;
- intx = digl->intx;
- hvm_pci_intx_assert(d, device, intx);
- hvm_irq_dpci->mirq[irq].pending++;
-
-#ifdef SUPPORT_MSI_REMAPPING
- if ( hvm_irq_dpci->mirq[irq].flags & HVM_IRQ_DPCI_TRANSLATE )
- {
- /* for translated MSI to INTx interrupt, eoi as early as
possible */
- __msi_pirq_eoi(d, irq);
- }
-#endif
- }
-
- /*
- * Set a timer to see if the guest can finish the interrupt or not. For
- * example, the guest OS may unmask the PIC during boot, before the
- * guest driver is loaded. hvm_pci_intx_assert() may succeed, but the
- * guest will never deal with the irq, then the physical interrupt line
- * will never be deasserted.
- */
- if ( pt_irq_need_timer(hvm_irq_dpci->mirq[irq].flags) )
- set_timer(&hvm_irq_dpci->hvm_timer[domain_irq_to_vector(d, irq)],
- NOW() + PT_IRQ_TIME_OUT);
- spin_unlock(&d->event_lock);
}
}
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