[Xen-devel] [PATCH 5/6] xen/arm: Only enable physical IRQs when the guest asks

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

From: Julien Grall <julien.grall@xxxxxxxxxx>

From: Julien Grall <julien.grall@xxxxxxxxxx>

Set/Unset IRQ_DISABLED from gic_irq_enable and gic_irq_disable.
Enable IRQs when the guest requests it, not unconditionally at boot time.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
 xen/arch/arm/gic.c  |   13 +++++++++----
 xen/arch/arm/vgic.c |    6 ++----
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index 5ec3ff9..72f978d 100644
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -137,6 +137,7 @@ static void gic_irq_enable(struct irq_desc *desc)
     /* Enable routing */
     enabler = GICD[GICD_ISENABLER + irq / 32];
     GICD[GICD_ISENABLER + irq / 32] = enabler | (1u << (irq % 32));
+    desc->status &= ~IRQ_DISABLED;
 }
 
 static void gic_irq_disable(struct irq_desc *desc)
@@ -145,6 +146,7 @@ static void gic_irq_disable(struct irq_desc *desc)
 
     /* Disable routing */
     GICD[GICD_ICENABLER + irq / 32] = (1u << (irq % 32));
+    desc->status |= IRQ_DISABLED;
 }
 
 static unsigned int gic_irq_startup(struct irq_desc *desc)
@@ -562,7 +564,6 @@ void __init release_irq(unsigned int irq)
     spin_lock_irqsave(&desc->lock,flags);
     action = desc->action;
     desc->action  = NULL;
-    desc->status |= IRQ_DISABLED;
     desc->status &= ~IRQ_GUEST;
 
     spin_lock(&gic.lock);
@@ -585,11 +586,8 @@ static int __setup_irq(struct irq_desc *desc, unsigned int 
irq,
         return -EBUSY;
 
     desc->action  = new;
-    desc->status &= ~IRQ_DISABLED;
     dsb();
 
-    desc->handler->startup(desc);
-
     return 0;
 }
 
@@ -605,6 +603,8 @@ int __init setup_dt_irq(const struct dt_irq *irq, struct 
irqaction *new)
 
     rc = __setup_irq(desc, irq->irq, new);
 
+    desc->handler->startup(desc);
+
     spin_unlock_irqrestore(&desc->lock, flags);
 
     return rc;
@@ -743,6 +743,7 @@ int gic_route_irq_to_guest(struct domain *d, const struct 
dt_irq *irq,
     unsigned long flags;
     int retval;
     bool_t level;
+    struct pending_irq *p;
 
     action = xmalloc(struct irqaction);
     if (!action)
@@ -769,6 +770,10 @@ int gic_route_irq_to_guest(struct domain *d, const struct 
dt_irq *irq,
         goto out;
     }
 
+    /* do not assume delivery to vcpu0 */
+    p = irq_to_pending(d->vcpu[0], irq->irq);
+    p->desc = desc;
+
 out:
     spin_unlock(&gic.lock);
     spin_unlock_irqrestore(&desc->lock, flags);
diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index 969ad2d..5b533ea 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -374,6 +374,8 @@ static void vgic_enable_irqs(struct vcpu *v, uint32_t r, 
int n)
         p = irq_to_pending(v, irq);
         if ( !list_empty(&p->inflight) && !(p->status & GIC_IRQ_GUEST_VISIBLE) 
)
             gic_set_guest_irq(v, irq, GICH_LR_PENDING, p->priority);
+        if ( p->desc != NULL && (p->desc->status & IRQ_DISABLED) )
+            p->desc->handler->enable(p->desc);
         i++;
     }
 
@@ -696,10 +698,6 @@ void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int 
irq, int virtual)
     n->irq = irq;
     n->status = GIC_IRQ_GUEST_PENDING;
     n->priority = priority;
-    if (!virtual)
-        n->desc = irq_to_desc(irq);
-    else
-        n->desc = NULL;
 
     /* the irq is enabled */
     if ( rank->ienable & (1 << (irq % 32)) )
-- 
1.7.10.4


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