[Xen-devel] [RFC v2 07/16] hack:vgic: move irq_to_pending out of lock

[Andrii Anisov <andrii.anisov@xxxxxxxxx>]

From: Andrii Anisov <andrii_anisov@xxxxxxxx>

For GICV2 pending_irq allocation is not concurrent, so reduce
some code under lock.

This code is not supposed to work with GICv3

Signed-off-by: Andrii Anisov <andrii_anisov@xxxxxxxx>
---
 xen/arch/arm/gic-v3-its.c | 2 ++
 xen/arch/arm/gic-v3-lpi.c | 2 ++
 xen/arch/arm/gic-v3.c     | 2 ++
 xen/arch/arm/vgic.c       | 9 ++++-----
 4 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
index ba4bc00..b1b890a 100644
--- a/xen/arch/arm/gic-v3-its.c
+++ b/xen/arch/arm/gic-v3-its.c
@@ -35,6 +35,8 @@
 
 #define ITS_CMD_QUEUE_SZ                SZ_1M
 
+#error "The current gic/vgic/domain code does not support GICv3"
+
 /*
  * No lock here, as this list gets only populated upon boot while scanning
  * firmware tables for all host ITSes, and only gets iterated afterwards.
diff --git a/xen/arch/arm/gic-v3-lpi.c b/xen/arch/arm/gic-v3-lpi.c
index e8c6e15..be64e17 100644
--- a/xen/arch/arm/gic-v3-lpi.c
+++ b/xen/arch/arm/gic-v3-lpi.c
@@ -32,6 +32,8 @@
 #include <asm/page.h>
 #include <asm/sysregs.h>
 
+#error "The current gic/vgic/domain code does not support GICv3"
+
 /*
  * There could be a lot of LPIs on the host side, and they always go to
  * a guest. So having a struct irq_desc for each of them would be wasteful
diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index 6fbc106..8e835b5 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -44,6 +44,8 @@
 #include <asm/io.h>
 #include <asm/sysregs.h>
 
+#error "The current gic/vgic/domain code does not support GICv3"
+
 /* Global state */
 static struct {
     void __iomem *map_dbase;  /* Mapped address of distributor registers */
diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index a795b6f..371576f 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -286,17 +286,16 @@ bool vgic_migrate_irq(struct vcpu *old, struct vcpu *new, 
unsigned int irq)
     ASSERT(!is_lpi(irq));
 #endif
 
-    spin_lock_irqsave(&old->arch.vgic.lock, flags);
-
     p = irq_to_pending(old, irq);
 
     /* nothing to do for virtual interrupts */
     if ( p->desc == NULL )
     {
-        spin_unlock_irqrestore(&old->arch.vgic.lock, flags);
         return true;
     }
 
+    spin_lock_irqsave(&old->arch.vgic.lock, flags);
+
     /* migration already in progress, no need to do anything */
     if ( test_bit(GIC_IRQ_GUEST_MIGRATING, &p->status) )
     {
@@ -588,8 +587,6 @@ void vgic_inject_irq(struct domain *d, struct vcpu *v, 
unsigned int virq,
         return;
     }
 
-    spin_lock_irqsave(&v->arch.vgic.lock, flags);
-
     n = irq_to_pending(v, virq);
 #ifdef CONFIG_GICV3
     /* If an LPI has been removed, there is nothing to inject here. */
@@ -600,6 +597,8 @@ void vgic_inject_irq(struct domain *d, struct vcpu *v, 
unsigned int virq,
     }
 #endif
 
+    spin_lock_irqsave(&v->arch.vgic.lock, flags);
+
     set_bit(GIC_IRQ_GUEST_QUEUED, &n->status);
 
     if ( !list_empty(&n->inflight) )
-- 
2.7.4


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