[PATCH v8 12/13] xen/arm: introduce GIC_PRI_TO_GUEST macro

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

GICH_LR registers and GICH_VMCR only support 5 bits for guest irq
priorities.
Introduce a macro to reduce the 8-bit priority fields to 5 bits; use it
in gic.c.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

---

Changes in v8:
- fix typo and hard tabs.
---
 xen/arch/arm/gic.c        |    2 +-
 xen/include/asm-arm/gic.h |    2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index de8dd1c..2bfaba9 100644
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -555,7 +555,7 @@ static inline void gic_set_lr(int lr, struct pending_irq *p,
     BUG_ON(lr < 0);
     BUG_ON(state & ~(GICH_LR_STATE_MASK<<GICH_LR_STATE_SHIFT));
 
-    lr_val = state | ((p->priority >> 3) << GICH_LR_PRIORITY_SHIFT) |
+    lr_val = state | (GIC_PRI_TO_GUEST(p->priority) << GICH_LR_PRIORITY_SHIFT) |
         ((p->irq & GICH_LR_VIRTUAL_MASK) << GICH_LR_VIRTUAL_SHIFT);
     if ( p->desc != NULL )
         lr_val |= GICH_LR_HW | (p->desc->irq << GICH_LR_PHYSICAL_SHIFT);
diff --git a/xen/include/asm-arm/gic.h b/xen/include/asm-arm/gic.h
index 30e92cf..bf6fb1e 100644
--- a/xen/include/asm-arm/gic.h
+++ b/xen/include/asm-arm/gic.h
@@ -152,6 +152,8 @@
 #define GIC_PRI_IRQ        0xa0
 #define GIC_PRI_IPI        0x90 /* IPIs must preempt normal interrupts */
 #define GIC_PRI_HIGHEST    0x80 /* Higher priorities belong to Secure-World */
+#define GIC_PRI_TO_GUEST(pri) (pri >> 3) /* GICH_LR and GICH_VMCR only support
+                                            5 bits for guest irq priority */
 
 
 #ifndef __ASSEMBLY__
-- 
1.7.10.4