xen: fix shared irq device passthrough

In driver/xen/events.c, whether bind_pirq is shareable or not is
determined by desc->action is NULL or not. But in __setup_irq,
startup(irq) is invoked before desc->action is assigned with
new action. So desc->action in startup_irq is always NULL, and
bind_pirq is always not shareable. This results in pt_irq_create_bind
failure when passthrough a device which shares irq to other devices.

This patch doesn't use probing_irq to determine if pirq is shareable
or not, instead set shareable flag in irq_info according to trigger
mode in xen_allocate_pirq. Set level triggered interrupts shareable.
Thus use this flag to set bind_pirq flag accordingly.

[v2: arch/x86/xen/pci.c no more, so file skipped]

Signed-off-by: Weidong Han <weidong.han@intel.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 4e0f868..cd50409 100644 (file)
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -97,6 +97,7 @@ struct irq_info
        } u;
 };
 #define PIRQ_NEEDS_EOI (1 << 0)
+#define PIRQ_SHAREABLE (1 << 1)
 
 static struct irq_info *irq_info;
 
@@ -445,6 +446,7 @@ static unsigned int startup_pirq(unsigned int irq)
        struct evtchn_bind_pirq bind_pirq;
        struct irq_info *info = info_for_irq(irq);
        int evtchn = evtchn_from_irq(irq);
+       int rc;
 
        BUG_ON(info->type != IRQT_PIRQ);
 
@@ -453,8 +455,10 @@ static unsigned int startup_pirq(unsigned int irq)
 
        bind_pirq.pirq = irq;
        /* NB. We are happy to share unless we are probing. */
-       bind_pirq.flags = probing_irq(irq) ? 0 : BIND_PIRQ__WILL_SHARE;
-       if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_pirq, &bind_pirq) != 0) {
+       bind_pirq.flags = info->u.pirq.flags & PIRQ_SHAREABLE ?
+                                       BIND_PIRQ__WILL_SHARE : 0;
+       rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_pirq, &bind_pirq);
+       if (rc != 0) {
                if (!probing_irq(irq))
                        printk(KERN_INFO "Failed to obtain physical IRQ %d\n",
                               irq);
@@ -564,7 +568,7 @@ static int find_irq_by_gsi(unsigned gsi)
  * event channel until the irq actually started up.  Return an
  * existing irq if we've already got one for the gsi.
  */
-int xen_allocate_pirq(unsigned gsi, char *name)
+int xen_allocate_pirq(unsigned gsi, int shareable, char *name)
 {
        int irq;
        struct physdev_irq irq_op;
@@ -596,6 +600,7 @@ int xen_allocate_pirq(unsigned gsi, char *name)
        }
 
        irq_info[irq] = mk_pirq_info(0, gsi, irq_op.vector);
+       irq_info[irq].u.pirq.flags |= shareable ? PIRQ_SHAREABLE : 0;
 
 out:
        spin_unlock(&irq_mapping_update_lock);

diff --git a/include/xen/events.h b/include/xen/events.h
index 2532f8b..d7a4ca7 100644 (file)
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -70,7 +70,7 @@ void xen_hvm_evtchn_do_upcall(void);
 /* Allocate an irq for a physical interrupt, given a gsi.  "Legacy"
  * GSIs are identity mapped; others are dynamically allocated as
  * usual. */
-int xen_allocate_pirq(unsigned gsi, char *name);
+int xen_allocate_pirq(unsigned gsi, int shareable, char *name);
 
 /* Return vector allocated to pirq */
 int xen_vector_from_irq(unsigned pirq);