[Xen-devel] [PATCH 1/7] xen: support pirq != irq

[stefano.stabellini@xxxxxxxxxxxxx]

From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

PHYSDEVOP_map_pirq might return a pirq different from what we asked if
we are running as an HVM guest, so we need to be able to support pirqs
that are different from linux irqs.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 drivers/xen/events.c |   49 +++++++++++++++++++++++++++++++++++++++++--------
 include/xen/events.h |    1 +
 2 files changed, 42 insertions(+), 8 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 395fd19..a5c30db 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -90,6 +90,7 @@ struct irq_info
                unsigned short virq;
                enum ipi_vector ipi;
                struct {
+                       unsigned short pirq;
                        unsigned short gsi;
                        unsigned char vector;
                        unsigned char flags;
@@ -100,6 +101,7 @@ struct irq_info
 #define PIRQ_SHAREABLE (1 << 1)
 
 static struct irq_info *irq_info;
+static int *pirq_to_irq;
 
 static int *evtchn_to_irq;
 struct cpu_evtchn_s {
@@ -146,11 +148,12 @@ static struct irq_info mk_virq_info(unsigned short 
evtchn, unsigned short virq)
                        .cpu = 0, .u.virq = virq };
 }
 
-static struct irq_info mk_pirq_info(unsigned short evtchn,
+static struct irq_info mk_pirq_info(unsigned short evtchn, unsigned short pirq,
                                    unsigned short gsi, unsigned short vector)
 {
        return (struct irq_info) { .type = IRQT_PIRQ, .evtchn = evtchn,
-                       .cpu = 0, .u.pirq = { .gsi = gsi, .vector = vector } };
+                       .cpu = 0,
+                       .u.pirq = { .pirq = pirq, .gsi = gsi, .vector = vector 
} };
 }
 
 /*
@@ -192,6 +195,16 @@ static unsigned virq_from_irq(unsigned irq)
        return info->u.virq;
 }
 
+static unsigned pirq_from_irq(unsigned irq)
+{
+       struct irq_info *info = info_for_irq(irq);
+
+       BUG_ON(info == NULL);
+       BUG_ON(info->type != IRQT_PIRQ);
+
+       return info->u.pirq.pirq;
+}
+
 static unsigned gsi_from_irq(unsigned irq)
 {
        struct irq_info *info = info_for_irq(irq);
@@ -364,6 +377,16 @@ static int get_nr_hw_irqs(void)
        return ret;
 }
 
+static int find_unbound_pirq(void)
+{
+       int i;
+       for (i = 0; i < nr_irqs; i++) {
+               if (pirq_to_irq[i] < 0)
+                       return i;
+       }
+       return -1;
+}
+
 static int find_unbound_irq(void)
 {
        int irq;
@@ -410,7 +433,7 @@ static bool identity_mapped_irq(unsigned irq)
 
 static void pirq_unmask_notify(int irq)
 {
-       struct physdev_eoi eoi = { .irq = irq };
+       struct physdev_eoi eoi = { .irq = pirq_from_irq(irq) };
 
        if (unlikely(pirq_needs_eoi(irq))) {
                int rc = HYPERVISOR_physdev_op(PHYSDEVOP_eoi, &eoi);
@@ -425,7 +448,7 @@ static void pirq_query_unmask(int irq)
 
        BUG_ON(info->type != IRQT_PIRQ);
 
-       irq_status.irq = irq;
+       irq_status.irq = pirq_from_irq(irq);
        if (HYPERVISOR_physdev_op(PHYSDEVOP_irq_status_query, &irq_status))
                irq_status.flags = 0;
 
@@ -453,7 +476,7 @@ static unsigned int startup_pirq(unsigned int irq)
        if (VALID_EVTCHN(evtchn))
                goto out;
 
-       bind_pirq.pirq = irq;
+       bind_pirq.pirq = pirq_from_irq(irq);
        /* NB. We are happy to share unless we are probing. */
        bind_pirq.flags = info->u.pirq.flags & PIRQ_SHAREABLE ?
                                        BIND_PIRQ__WILL_SHARE : 0;
@@ -556,12 +579,17 @@ static int find_irq_by_gsi(unsigned gsi)
        return -1;
 }
 
+int xen_allocate_pirq(unsigned gsi, int shareable, char *name)
+{
+       return xen_map_pirq_gsi(gsi, gsi, shareable, name);
+}
+
 /*
  * Allocate a physical irq, along with a vector.  We don't assign an
  * 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, int shareable, char *name)
+int xen_map_pirq_gsi(unsigned pirq, unsigned gsi, int shareable, char *name)
 {
        int irq;
        struct physdev_irq irq_op;
@@ -570,7 +598,7 @@ int xen_allocate_pirq(unsigned gsi, int shareable, char 
*name)
 
        irq = find_irq_by_gsi(gsi);
        if (irq != -1) {
-               printk(KERN_INFO "xen_allocate_pirq: returning irq %d for gsi 
%u\n",
+               printk(KERN_INFO "xen_map_pirq_gsi: returning irq %d for gsi 
%u\n",
                       irq, gsi);
                goto out;       /* XXX need refcount? */
        }
@@ -600,8 +628,9 @@ int xen_allocate_pirq(unsigned gsi, int shareable, char 
*name)
                goto out;
        }
 
-       irq_info[irq] = mk_pirq_info(0, gsi, irq_op.vector);
+       irq_info[irq] = mk_pirq_info(0, pirq, gsi, irq_op.vector);
        irq_info[irq].u.pirq.flags |= shareable ? PIRQ_SHAREABLE : 0;
+       pirq_to_irq[pirq] = irq;
 
 out:
        spin_unlock(&irq_mapping_update_lock);
@@ -1311,6 +1340,10 @@ void __init xen_init_IRQ(void)
                                    GFP_KERNEL);
        irq_info = kcalloc(nr_irqs, sizeof(*irq_info), GFP_KERNEL);
 
+       pirq_to_irq = kcalloc(nr_irqs, sizeof(*pirq_to_irq), GFP_KERNEL);
+       for (i = 0; i < nr_irqs; i++)
+               pirq_to_irq[i] = -1;
+
        evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
                                    GFP_KERNEL);
        for (i = 0; i < NR_EVENT_CHANNELS; i++)
diff --git a/include/xen/events.h b/include/xen/events.h
index 2f70de4..b276c38 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -71,6 +71,7 @@ void xen_hvm_evtchn_do_upcall(void);
    GSIs are identity mapped; others are dynamically allocated as
    usual. */
 int xen_allocate_pirq(unsigned gsi, int shareable, char *name);
+int xen_map_pirq_gsi(unsigned pirq, unsigned gsi, int shareable, char *name);
 
 /* De-allocates the above mentioned physical interrupt. */
 int xen_destroy_irq(int irq);
-- 
1.5.6.5


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