[PATCH] ARM/vgic: Use for_each_set_bit() in vgic_to_sgi()

[Andrew Cooper]

The existing expression is just a very complicated way of expressing a loop
over all bits of target->list.  Simplify the expression.

While here, fix the two gprintk()'s.  Because of a quotes vs line continuation
issue, there's a long string of spaces in the middle of the format string.

  $ strings xen-syms-arm32 | grep -e VGIC -e GICD_SGIR
  <G><1>%pv VGIC: write r=%08x                         target->list=%hx, wrong 
CPUTargetList
  <G><1>%pv vGICD:unhandled GICD_SGIR write %08x                  with wrong 
mode

not to mention trailing whitespace too.

Rewrite them to be more consise and more useful.  Use 0x prefixes for hex,
rather than ambigous, and identify the problem target vCPU / mode, rather than
simply saying somethign was wrong.

Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
---
CC: Stefano Stabellini <sstabell...@kernel.org>
CC: Julien Grall <jul...@xen.org>
CC: Volodymyr Babchuk <volodymyr_babc...@epam.com>
CC: Bertrand Marquis <bertrand.marq...@arm.com>
CC: Michal Orzel <michal.or...@amd.com>
CC: Jan Beulich <jbeul...@suse.com>

In a fun twist, we can't use target->list directly in the expresion, because
the typeof() picks up constness from the pointer, and we get:

  In file included from arch/arm/vgic.c:11:
  arch/arm/vgic.c: In function ‘vgic_to_sgi’:
  ./include/xen/bitops.h:305:19: error: assignment of read-only variable ‘__v’
    305 |               __v &= __v - 1 )
        |                   ^~
  arch/arm/vgic.c:483:9: note: in expansion of macro ‘for_each_set_bit’
    483 |         for_each_set_bit ( i, target->list )
        |         ^~~~~~~~~~~~~~~~

Sadly we need -std=c23 before we can use typeof_unqual() which is what we
actually want here.
---
 xen/arch/arm/vgic.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index 7b54ccc7cbfa..081cbb67fb52 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -470,8 +470,7 @@ bool vgic_to_sgi(struct vcpu *v, register_t sgir, enum 
gic_sgi_mode irqmode,
     struct domain *d = v->domain;
     int vcpuid;
     int i;
-    unsigned int base;
-    unsigned long int bitmap;
+    unsigned int base, bitmap;
 
     ASSERT( virq < 16 );
 
@@ -481,15 +480,16 @@ bool vgic_to_sgi(struct vcpu *v, register_t sgir, enum 
gic_sgi_mode irqmode,
         perfc_incr(vgic_sgi_list);
         base = target->aff1 << 4;
         bitmap = target->list;
-        bitmap_for_each ( i, &bitmap, sizeof(target->list) * 8 )
+
+        for_each_set_bit ( i, bitmap )
         {
             vcpuid = base + i;
             if ( vcpuid >= d->max_vcpus || d->vcpu[vcpuid] == NULL ||
                  !is_vcpu_online(d->vcpu[vcpuid]) )
             {
-                gprintk(XENLOG_WARNING, "VGIC: write r=%"PRIregister" \
-                        target->list=%hx, wrong CPUTargetList \n",
-                        sgir, target->list);
+                gprintk(XENLOG_WARNING,
+                        "vGIC: write %#"PRIregister", target->list=%#x, bad 
target v%d\n",
+                        sgir, target->list, vcpuid);
                 continue;
             }
             vgic_inject_irq(d, d->vcpu[vcpuid], virq, true);
@@ -510,8 +510,8 @@ bool vgic_to_sgi(struct vcpu *v, register_t sgir, enum 
gic_sgi_mode irqmode,
         break;
     default:
         gprintk(XENLOG_WARNING,
-                "vGICD:unhandled GICD_SGIR write %"PRIregister" \
-                 with wrong mode\n", sgir);
+                "vGICD: GICD_SGIR write %#"PRIregister" with unhangled mode 
%d\n",
+                sgir, irqmode);
         return false;
     }
 
-- 
2.39.2