[PATCH 4/4] ARM/vgic: Use for_each_set_bit() in vgic-mmio*

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

These are all loops over a scalar value, and don't need to call general bitop
helpers behind the scenes.

No functional change.

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>

Slighly RFC.  It's unclear whether len is the size of the register, or the
size of the access.  For sub-GPR accesses, won't the upper bits be clear
anyway?  If so, this can be simplified further.

$ ../scripts/bloat-o-meter xen-syms-arm64-{before,after}
add/remove: 0/0 grow/shrink: 2/5 up/down: 20/-140 (-120)
Function                                     old     new   delta
vgic_mmio_write_spending                     320     332     +12
vgic_mmio_write_cpending                     368     376      +8
vgic_mmio_write_sactive                      192     176     -16
vgic_mmio_write_cactive                      192     176     -16
vgic_mmio_write_cenable                      316     288     -28
vgic_mmio_write_senable                      320     284     -36
vgic_mmio_write_sgir                         344     300     -44

$ ../scripts/bloat-o-meter xen-syms-arm32-{before,after}
add/remove: 0/0 grow/shrink: 0/4 up/down: 0/-32 (-32)
Function                                     old     new   delta
vgic_mmio_write_sactive                      204     200      -4
vgic_mmio_write_cpending                     464     460      -4
vgic_mmio_write_cactive                      204     200      -4
vgic_mmio_write_sgir                         336     316     -20
---
 xen/arch/arm/vgic/vgic-mmio-v2.c |  3 +--
 xen/arch/arm/vgic/vgic-mmio.c    | 36 +++++++++++++++++++++-----------
 2 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/xen/arch/arm/vgic/vgic-mmio-v2.c b/xen/arch/arm/vgic/vgic-mmio-v2.c
index 670b335db2c3..42fac0403f07 100644
--- a/xen/arch/arm/vgic/vgic-mmio-v2.c
+++ b/xen/arch/arm/vgic/vgic-mmio-v2.c
@@ -90,7 +90,6 @@ static void vgic_mmio_write_sgir(struct vcpu *source_vcpu,
     unsigned int intid = val & GICD_SGI_INTID_MASK;
     unsigned long targets = (val & GICD_SGI_TARGET_MASK) >>
                             GICD_SGI_TARGET_SHIFT;
-    unsigned int vcpu_id;
 
     switch ( val & GICD_SGI_TARGET_LIST_MASK )
     {
@@ -108,7 +107,7 @@ static void vgic_mmio_write_sgir(struct vcpu *source_vcpu,
         return;
     }
 
-    bitmap_for_each ( vcpu_id, &targets, 8 )
+    for_each_set_bit ( vcpu_id, (uint8_t)targets )
     {
         struct vcpu *vcpu = d->vcpu[vcpu_id];
         struct vgic_irq *irq = vgic_get_irq(d, vcpu, intid);
diff --git a/xen/arch/arm/vgic/vgic-mmio.c b/xen/arch/arm/vgic/vgic-mmio.c
index bd4caf7fc326..f7c336a238ab 100644
--- a/xen/arch/arm/vgic/vgic-mmio.c
+++ b/xen/arch/arm/vgic/vgic-mmio.c
@@ -69,9 +69,11 @@ void vgic_mmio_write_senable(struct vcpu *vcpu,
                              unsigned long val)
 {
     uint32_t intid = VGIC_ADDR_TO_INTID(addr, 1);
-    unsigned int i;
 
-    bitmap_for_each ( i, &val, len * 8 )
+    if ( len < sizeof(val) )
+        val &= (1UL << (len * 8)) - 1;
+
+    for_each_set_bit ( i, val )
     {
         struct vgic_irq *irq = vgic_get_irq(vcpu->domain, vcpu, intid + i);
         unsigned long flags;
@@ -114,9 +116,11 @@ void vgic_mmio_write_cenable(struct vcpu *vcpu,
                              unsigned long val)
 {
     uint32_t intid = VGIC_ADDR_TO_INTID(addr, 1);
-    unsigned int i;
 
-    bitmap_for_each ( i, &val, len * 8 )
+    if ( len < sizeof(val) )
+        val &= (1UL << (len * 8)) - 1;
+
+    for_each_set_bit ( i, val )
     {
         struct vgic_irq *irq;
         unsigned long flags;
@@ -182,11 +186,13 @@ void vgic_mmio_write_spending(struct vcpu *vcpu,
                               unsigned long val)
 {
     uint32_t intid = VGIC_ADDR_TO_INTID(addr, 1);
-    unsigned int i;
     unsigned long flags;
     irq_desc_t *desc;
 
-    bitmap_for_each ( i, &val, len * 8 )
+    if ( len < sizeof(val) )
+        val &= (1UL << (len * 8)) - 1;
+
+    for_each_set_bit ( i, val )
     {
         struct vgic_irq *irq = vgic_get_irq(vcpu->domain, vcpu, intid + i);
 
@@ -230,11 +236,13 @@ void vgic_mmio_write_cpending(struct vcpu *vcpu,
                               unsigned long val)
 {
     uint32_t intid = VGIC_ADDR_TO_INTID(addr, 1);
-    unsigned int i;
     unsigned long flags;
     irq_desc_t *desc;
 
-    bitmap_for_each ( i, &val, len * 8 )
+    if ( len < sizeof(val) )
+        val &= (1UL << (len * 8)) - 1;
+
+    for_each_set_bit ( i, val )
     {
         struct vgic_irq *irq = vgic_get_irq(vcpu->domain, vcpu, intid + i);
 
@@ -326,9 +334,11 @@ void vgic_mmio_write_cactive(struct vcpu *vcpu,
                              unsigned long val)
 {
     uint32_t intid = VGIC_ADDR_TO_INTID(addr, 1);
-    unsigned int i;
 
-    bitmap_for_each ( i, &val, len * 8 )
+    if ( len < sizeof(val) )
+        val &= (1UL << (len * 8)) - 1;
+
+    for_each_set_bit ( i, val )
     {
         struct vgic_irq *irq = vgic_get_irq(vcpu->domain, vcpu, intid + i);
 
@@ -356,9 +366,11 @@ void vgic_mmio_write_sactive(struct vcpu *vcpu,
                              unsigned long val)
 {
     uint32_t intid = VGIC_ADDR_TO_INTID(addr, 1);
-    unsigned int i;
 
-    bitmap_for_each ( i, &val, len * 8 )
+    if ( len < sizeof(val) )
+        val &= (1UL << (len * 8)) - 1;
+
+    for_each_set_bit ( i, val )
     {
         struct vgic_irq *irq = vgic_get_irq(vcpu->domain, vcpu, intid + i);
 
-- 
2.39.2