[PATCH 5/6] ARM/vgic: Use for_each_set_bit() in vgic_set_irqs_pending()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

... which is better optimised for scalar values, rather than using the
arbitrary-sized bitmap helpers.

For ARM32:

  add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-16 (-16)
  Function                                     old     new   delta
  vgic_set_irqs_pending                        284     268     -16

including removing calls to _find_{first,next}_bit_le(), and two stack-spilled
words too.

For ARM64:

  add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-40 (-40)
  Function                                     old     new   delta
  vgic_set_irqs_pending                        268     228     -40

including removing three calls to find_next_bit().

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Julien Grall <julien@xxxxxxx>
CC: Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
CC: Bertrand Marquis <bertrand.marquis@xxxxxxx>
CC: Michal Orzel <michal.orzel@xxxxxxx>

TODO: These were debug builds, and I need to redo the analysis with release
builds.  Also extend to the other examples.
---
 xen/arch/arm/vgic.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index 57519e834d78..c060676aee78 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -421,15 +421,13 @@ void vgic_enable_irqs(struct vcpu *v, uint32_t r, 
unsigned int n)
 
 void vgic_set_irqs_pending(struct vcpu *v, uint32_t r, unsigned int rank)
 {
-    const unsigned long mask = r;
-    unsigned int i;
     /* The first rank is always per-vCPU */
     bool private = rank == 0;
 
     /* LPIs will never be set pending via this function */
     ASSERT(!is_lpi(32 * rank + 31));
 
-    bitmap_for_each( i, &mask, 32 )
+    for_each_set_bit ( i, r )
     {
         unsigned int irq = i + 32 * rank;
 
-- 
2.39.2