[Xen-changelog] [xen master] ARM: VGIC: factor out vgic_connect_hw_irq()

[patchbot@xxxxxxx]

commit ec2a2f1de4a98bef1f0d993b2fea6b750223d1fc
Author:     Andre Przywara <andre.przywara@xxxxxxxxxx>
AuthorDate: Tue Feb 6 17:09:00 2018 +0000
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Thu Feb 8 13:18:11 2018 -0800

    ARM: VGIC: factor out vgic_connect_hw_irq()
    
    At the moment we happily access VGIC internal data structures like
    the rank and struct pending_irq in gic.c, which should be VGIC agnostic.
    
    Factor out a new function vgic_connect_hw_irq(), which allows a virtual
    IRQ to be connected to a hardware IRQ (using the hw bit in the LR).
    
    This removes said accesses to VGIC data structures and improves abstraction.
    
    One thing to note is that this changes the locking scheme slightly:
    we hold the rank lock for a shorter period of time, not covering some
    of the later lines, which deal with the "irq_desc" structure only. This
    should not have any adverse effect, but is a change in locking anyway.
    
    Signed-off-by: Andre Przywara <andre.przywara@xxxxxxxxxx>
    Reviewed-by: Julien Grall <julien.grall@xxxxxxx>
---
 xen/arch/arm/gic-vgic.c    | 41 +++++++++++++++++++++++++++++++++++++++++
 xen/arch/arm/gic.c         | 44 ++++++++++----------------------------------
 xen/include/asm-arm/vgic.h |  2 ++
 3 files changed, 53 insertions(+), 34 deletions(-)

diff --git a/xen/arch/arm/gic-vgic.c b/xen/arch/arm/gic-vgic.c
index 8221ae5..820e464 100644
--- a/xen/arch/arm/gic-vgic.c
+++ b/xen/arch/arm/gic-vgic.c
@@ -397,6 +397,47 @@ void gic_dump_vgic_info(struct vcpu *v)
         printk("Pending irq=%d\n", p->irq);
 }
 
+int vgic_connect_hw_irq(struct domain *d, struct vcpu *v, unsigned int virq,
+                        struct irq_desc *desc, bool connect)
+{
+    unsigned long flags;
+    /*
+     * Use vcpu0 to retrieve the pending_irq struct. Given that we only
+     * route SPIs to guests, it doesn't make any difference.
+     */
+    struct vcpu *v_target = vgic_get_target_vcpu(d->vcpu[0], virq);
+    struct vgic_irq_rank *rank = vgic_rank_irq(v_target, virq);
+    struct pending_irq *p = irq_to_pending(v_target, virq);
+    int ret = 0;
+
+    /* "desc" is optional when we disconnect an IRQ. */
+    ASSERT(connect && desc);
+
+    /* We are taking to rank lock to prevent parallel connections. */
+    vgic_lock_rank(v_target, rank, flags);
+
+    if ( connect )
+    {
+        /* The VIRQ should not be already enabled by the guest */
+        if ( !p->desc &&
+             !test_bit(GIC_IRQ_GUEST_ENABLED, &p->status) )
+            p->desc = desc;
+        else
+            ret = -EBUSY;
+    }
+    else
+    {
+        if ( desc && p->desc != desc )
+            ret = -EINVAL;
+        else
+            p->desc = NULL;
+    }
+
+    vgic_unlock_rank(v_target, rank, flags);
+
+    return ret;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index 4cb74d4..968e46f 100644
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -128,13 +128,7 @@ void gic_route_irq_to_xen(struct irq_desc *desc, unsigned 
int priority)
 int gic_route_irq_to_guest(struct domain *d, unsigned int virq,
                            struct irq_desc *desc, unsigned int priority)
 {
-    unsigned long flags;
-    /* Use vcpu0 to retrieve the pending_irq struct. Given that we only
-     * route SPIs to guests, it doesn't make any difference. */
-    struct vcpu *v_target = vgic_get_target_vcpu(d->vcpu[0], virq);
-    struct vgic_irq_rank *rank = vgic_rank_irq(v_target, virq);
-    struct pending_irq *p = irq_to_pending(v_target, virq);
-    int res = -EBUSY;
+    int ret;
 
     ASSERT(spin_is_locked(&desc->lock));
     /* Caller has already checked that the IRQ is an SPI */
@@ -142,12 +136,9 @@ int gic_route_irq_to_guest(struct domain *d, unsigned int 
virq,
     ASSERT(virq < vgic_num_irqs(d));
     ASSERT(!is_lpi(virq));
 
-    vgic_lock_rank(v_target, rank, flags);
-
-    if ( p->desc ||
-         /* The VIRQ should not be already enabled by the guest */
-         test_bit(GIC_IRQ_GUEST_ENABLED, &p->status) )
-        goto out;
+    ret = vgic_connect_hw_irq(d, NULL, virq, desc, true);
+    if ( ret )
+        return ret;
 
     desc->handler = gic_hw_ops->gic_guest_irq_type;
     set_bit(_IRQ_GUEST, &desc->status);
@@ -156,31 +147,19 @@ int gic_route_irq_to_guest(struct domain *d, unsigned int 
virq,
         gic_set_irq_type(desc, desc->arch.type);
     gic_set_irq_priority(desc, priority);
 
-    p->desc = desc;
-    res = 0;
-
-out:
-    vgic_unlock_rank(v_target, rank, flags);
-
-    return res;
+    return 0;
 }
 
 /* This function only works with SPIs for now */
 int gic_remove_irq_from_guest(struct domain *d, unsigned int virq,
                               struct irq_desc *desc)
 {
-    struct vcpu *v_target = vgic_get_target_vcpu(d->vcpu[0], virq);
-    struct vgic_irq_rank *rank = vgic_rank_irq(v_target, virq);
-    struct pending_irq *p = irq_to_pending(v_target, virq);
-    unsigned long flags;
+    int ret;
 
     ASSERT(spin_is_locked(&desc->lock));
     ASSERT(test_bit(_IRQ_GUEST, &desc->status));
-    ASSERT(p->desc == desc);
     ASSERT(!is_lpi(virq));
 
-    vgic_lock_rank(v_target, rank, flags);
-
     if ( d->is_dying )
     {
         desc->handler->shutdown(desc);
@@ -198,19 +177,16 @@ int gic_remove_irq_from_guest(struct domain *d, unsigned 
int virq,
          */
         if ( test_bit(_IRQ_INPROGRESS, &desc->status) ||
              !test_bit(_IRQ_DISABLED, &desc->status) )
-        {
-            vgic_unlock_rank(v_target, rank, flags);
             return -EBUSY;
-        }
     }
 
+    ret = vgic_connect_hw_irq(d, NULL, virq, desc, false);
+    if ( ret )
+        return ret;
+
     clear_bit(_IRQ_GUEST, &desc->status);
     desc->handler = &no_irq_type;
 
-    p->desc = NULL;
-
-    vgic_unlock_rank(v_target, rank, flags);
-
     return 0;
 }
 
diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h
index 22c8502..fda0823 100644
--- a/xen/include/asm-arm/vgic.h
+++ b/xen/include/asm-arm/vgic.h
@@ -219,6 +219,8 @@ int vgic_v2_init(struct domain *d, int *mmio_count);
 int vgic_v3_init(struct domain *d, int *mmio_count);
 
 bool vgic_evtchn_irq_pending(struct vcpu *v);
+int vgic_connect_hw_irq(struct domain *d, struct vcpu *v, unsigned int virq,
+                        struct irq_desc *desc, bool connect);
 
 extern int domain_vgic_register(struct domain *d, int *mmio_count);
 extern int vcpu_vgic_free(struct vcpu *v);
--
generated by git-patchbot for /home/xen/git/xen.git#master

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