This implements a simple way to express the case of IRQ routing where
there is one in-kernel PIC and the system interrupts (GSIs) are routed
1-1 to the corresponding pins of the PIC. This is expressed by having
kvm->irq_routing == NULL with a skeleton irq routing entry in the new
kvm->default_irq_route field.
This provides a convenient way to provide backwards compatibility when
adding IRQ routing capability to an existing in-kernel PIC, such as the
XICS emulation on powerpc.
Signed-off-by: Paul Mackerras <paulus@xxxxxxxxx>
---
include/linux/kvm_host.h | 1 +
virt/kvm/eventfd.c | 4 ++++
virt/kvm/irqchip.c | 23 ++++++++++++++++++++---
3 files changed, 25 insertions(+), 3 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 749bdb1..609f587 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -394,6 +394,7 @@ struct kvm {
* if configured, irqfds.lock.
*/
struct kvm_irq_routing_table __rcu *irq_routing;
+ struct kvm_kernel_irq_routing_entry default_irq_route;
struct hlist_head mask_notifier_list;
struct hlist_head irq_ack_notifier_list;
#endif
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index abe4d60..7010cb3 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -272,6 +272,10 @@ static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd,
{
struct kvm_kernel_irq_routing_entry *e;
+ if (!irq_rt) {
+ rcu_assign_pointer(irqfd->irq_entry, NULL);
+ return;
+ }
if (irqfd->gsi >= irq_rt->nr_rt_entries) {
rcu_assign_pointer(irqfd->irq_entry, NULL);
return;
diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
index 20dc9e4..ebc2941 100644
--- a/virt/kvm/irqchip.c
+++ b/virt/kvm/irqchip.c
@@ -30,13 +30,24 @@
#include <trace/events/kvm.h>
#include "irq.h"
+static inline int pin_to_gsi(struct kvm *kvm, unsigned irqchip, unsigned pin)
+{
+ struct kvm_irq_routing_table *rt;
+ int gsi = pin;
+
+ rt = rcu_dereference(kvm->irq_routing);
+ if (rt)
+ gsi = rt->chip[irqchip][pin];
+ return gsi;
+}
+
bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin)
{
struct kvm_irq_ack_notifier *kian;
int gsi;
rcu_read_lock();
- gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
+ gsi = pin_to_gsi(kvm, irqchip, pin);
if (gsi != -1)
hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
link)
@@ -59,7 +70,7 @@ void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
trace_kvm_ack_irq(irqchip, pin);
rcu_read_lock();
- gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
+ gsi = pin_to_gsi(kvm, irqchip, pin);
if (gsi != -1)
hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
link)
@@ -126,7 +137,13 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
*/
rcu_read_lock();
irq_rt = rcu_dereference(kvm->irq_routing);
- if (irq < irq_rt->nr_rt_entries)
+ if (!irq_rt) {
+ if (kvm->default_irq_route.set) {
+ irq_set[i] = kvm->default_irq_route;
+ irq_set[i].gsi = irq;
+ irq_set[i++].irqchip.pin = irq;
+ }
+ } else if (irq < irq_rt->nr_rt_entries)
hlist_for_each_entry(e, &irq_rt->map[irq], link)
irq_set[i++] = *e;
rcu_read_unlock();
--
1.8.4.rc3
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