On 03.10.2011 19:24, Stefano Stabellini wrote:
> I am going to send a different patch upstream for Xen 4.2, because I
> would also like it to cover the very unlikely scenario in which a PV
> guest (like dom0 or a PV guest with PCI passthrough) is loosing level
> interrupts because when Xen tries to set the corresponding event channel
> pending the bit is alreay set. The codebase is different enough that
> making the same change on 4.1 is non-trivial. I am appending the new
> patch to this email, it would be great if you could test it. You just
> need a 4.2 hypervisor, not the entire system. You should be able to
> perform the test updating only xen.gz.
> If you have trouble if xen-unstable.hg tip, try changeset 23843.
Hi Stefano,
currently I would have the problem that I don't have too much time to move to
another hypervisor (tests may or may not be useful there with substantial
changes beside this one) with our next release being close.
But I think I got a usable backport of your change to 4.1.1 (you think it looks
ok?) and have given that a quick test which seems to be ok...
Though one drawback is that I don't have a setup which would use passthrough, so
that path is not tested. I think I did see (with a debugging version) that the
lost count was incremented and decremented in dom0, though.
-Stefan
---
Index: xen-4.1.1/xen/arch/x86/domain.c
===================================================================
--- xen-4.1.1.orig/xen/arch/x86/domain.c 2011-10-05 15:03:19.405815293
+0200
+++ xen-4.1.1/xen/arch/x86/domain.c 2011-10-05 15:09:59.781816622 +0200
@@ -514,6 +514,12 @@ int arch_domain_create(struct domain *d,
memset(d->arch.pirq_irq, 0,
d->nr_pirqs * sizeof(*d->arch.pirq_irq));
+ d->arch.pirq_lost = xmalloc_array(int, d->nr_pirqs);
+ if ( !d->arch.pirq_lost)
+ goto fail;
+ memset(d->arch.pirq_lost, 0,
+ d->nr_pirqs * sizeof(*d->arch.pirq_lost));
+
d->arch.irq_pirq = xmalloc_array(int, nr_irqs);
if ( !d->arch.irq_pirq )
goto fail;
@@ -575,6 +581,7 @@ int arch_domain_create(struct domain *d,
fail:
d->is_dying = DOMDYING_dead;
vmce_destroy_msr(d);
+ xfree(d->arch.pirq_lost);
xfree(d->arch.pirq_irq);
xfree(d->arch.irq_pirq);
xfree(d->arch.pirq_emuirq);
@@ -628,6 +635,7 @@ void arch_domain_destroy(struct domain *
#endif
free_xenheap_page(d->shared_info);
+ xfree(d->arch.pirq_lost);
xfree(d->arch.pirq_irq);
xfree(d->arch.irq_pirq);
xfree(d->arch.pirq_emuirq);
Index: xen-4.1.1/xen/arch/x86/hvm/irq.c
===================================================================
--- xen-4.1.1.orig/xen/arch/x86/hvm/irq.c 2011-10-05 15:14:35.441815292
+0200
+++ xen-4.1.1/xen/arch/x86/hvm/irq.c 2011-10-05 17:55:43.603986605 +0200
@@ -33,7 +33,9 @@ static void assert_gsi(struct domain *d,
int pirq = domain_emuirq_to_pirq(d, ioapic_gsi);
if ( hvm_domain_use_pirq(d, pirq) )
{
- send_guest_pirq(d, pirq);
+ if ( send_guest_pirq(d, pirq) && ioapic_gsi >= NR_ISAIRQS )
+ if (d->arch.pirq_lost)
+ d->arch.pirq_lost[pirq]++;
return;
}
vioapic_irq_positive_edge(d, ioapic_gsi);
@@ -67,6 +69,12 @@ static void __hvm_pci_intx_assert(
gsi = hvm_pci_intx_gsi(device, intx);
if ( hvm_irq->gsi_assert_count[gsi]++ == 0 )
assert_gsi(d, gsi);
+ else {
+ int pirq = domain_emuirq_to_pirq(d, gsi);
+
+ if ( hvm_domain_use_pirq(d, pirq) && d->arch.pirq_lost)
+ d->arch.pirq_lost[pirq]++;
+ }
link = hvm_pci_intx_link(device, intx);
isa_irq = hvm_irq->pci_link.route[link];
Index: xen-4.1.1/xen/arch/x86/irq.c
===================================================================
--- xen-4.1.1.orig/xen/arch/x86/irq.c 2011-10-05 15:26:58.477815292 +0200
+++ xen-4.1.1/xen/arch/x86/irq.c 2011-10-05 17:56:23.191986535 +0200
@@ -888,10 +888,13 @@ static void __do_IRQ_guest(int irq)
desc->status |= IRQ_INPROGRESS; /* cleared during hvm eoi */
}
}
- else if ( send_guest_pirq(d, pirq) &&
- (action->ack_type == ACKTYPE_NONE) )
- {
- already_pending++;
+ else {
+ if ( send_guest_pirq(d, pirq) ) {
+ if ( action->ack_type == ACKTYPE_EOI && d->arch.pirq_lost)
+ d->arch.pirq_lost[pirq]++;
+ else if ( action->ack_type == ACKTYPE_NONE )
+ already_pending++;
+ }
}
}
Index: xen-4.1.1/xen/arch/x86/physdev.c
===================================================================
--- xen-4.1.1.orig/xen/arch/x86/physdev.c 2011-10-05 15:36:14.545815292
+0200
+++ xen-4.1.1/xen/arch/x86/physdev.c 2011-10-05 17:57:06.055986460 +0200
@@ -261,13 +261,18 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_H
ret = -EINVAL;
if ( eoi.irq >= v->domain->nr_pirqs )
break;
+ spin_lock(&v->domain->event_lock);
if ( v->domain->arch.pirq_eoi_map )
evtchn_unmask(v->domain->pirq_to_evtchn[eoi.irq]);
if ( !is_hvm_domain(v->domain) ||
domain_pirq_to_irq(v->domain, eoi.irq) > 0 )
- ret = pirq_guest_eoi(v->domain, eoi.irq);
- else
- ret = 0;
+ pirq_guest_eoi(v->domain, eoi.irq);
+ if ( v->domain->arch.pirq_lost && v->domain->arch.pirq_lost[eoi.irq]) {
+ if ( !send_guest_pirq(v->domain, eoi.irq) )
+ v->domain->arch.pirq_lost[eoi.irq]--;
+ }
+ ret = 0;
+ spin_unlock(&v->domain->event_lock);
break;
}
@@ -323,9 +328,10 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_H
break;
irq_status_query.flags = 0;
if ( is_hvm_domain(v->domain) &&
- domain_pirq_to_irq(v->domain, irq) <= 0 )
+ domain_pirq_to_irq(v->domain, irq) <= 0 &&
+ domain_pirq_to_emuirq(v->domain, irq) == IRQ_UNBOUND )
{
- ret = copy_to_guest(arg, &irq_status_query, 1) ? -EFAULT : 0;
+ ret = -EINVAL;
break;
}
Index: xen-4.1.1/xen/include/asm-x86/domain.h
===================================================================
--- xen-4.1.1.orig/xen/include/asm-x86/domain.h 2011-10-05 15:10:11.709815293
+0200
+++ xen-4.1.1/xen/include/asm-x86/domain.h 2011-10-05 15:12:46.237815276
+0200
@@ -312,6 +312,9 @@ struct arch_domain
(possibly other cases in the future */
uint64_t vtsc_kerncount; /* for hvm, counts all vtsc */
uint64_t vtsc_usercount; /* not used for hvm */
+
+ /* Protected by d->event_lock, count of lost pirqs */
+ int *pirq_lost;
} __cacheline_aligned;
#define has_arch_pdevs(d) (!list_empty(&(d)->arch.pdev_list))
xen-backport-pirq-lost.patch
Description: Text Data
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