[xen staging] ARM/vgic: Use for_each_set_bit() in vgic_mmio_write_sgir()

[patchbot@xxxxxxx]

commit eeb679da8f8d5d96948315ce30e4d750be6a1f51
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Fri Aug 30 14:25:28 2024 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Thu Mar 27 11:54:23 2025 +0000

    ARM/vgic: Use for_each_set_bit() in vgic_mmio_write_sgir()
    
    The bitmap_for_each() expression only inspects the bottom 8 bits of targets.
    Change it's type to uint8_t and use for_each_set_bit() which is more 
efficient
    over scalars.
    
    GICD_SGI_TARGET_LIST_MASK is 2 bits wide.  Two cases discard the prior
    calculation of targets, and one case exits early.
    
    Therefore, move the GICD_SGI_TARGET_MASK calculation into the only case 
which
    wants it, and use MASK_EXTR() to simplify the expression.
    
    No functional change.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
---
 xen/arch/arm/vgic/vgic-mmio-v2.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/xen/arch/arm/vgic/vgic-mmio-v2.c b/xen/arch/arm/vgic/vgic-mmio-v2.c
index 7d1391ac9b..b7c2d7ce99 100644
--- a/xen/arch/arm/vgic/vgic-mmio-v2.c
+++ b/xen/arch/arm/vgic/vgic-mmio-v2.c
@@ -88,13 +88,12 @@ static void vgic_mmio_write_sgir(struct vcpu *source_vcpu,
     struct domain *d = source_vcpu->domain;
     unsigned int nr_vcpus = d->max_vcpus;
     unsigned int intid = val & GICD_SGI_INTID_MASK;
-    unsigned long targets = (val & GICD_SGI_TARGET_MASK) >>
-                            GICD_SGI_TARGET_SHIFT;
-    unsigned int vcpu_id;
+    uint8_t targets = 0;
 
     switch ( val & GICD_SGI_TARGET_LIST_MASK )
     {
     case GICD_SGI_TARGET_LIST:                    /* as specified by targets */
+        targets = MASK_EXTR(val, GICD_SGI_TARGET_MASK);
         targets &= GENMASK(nr_vcpus - 1, 0);      /* limit to existing VCPUs */
         break;
     case GICD_SGI_TARGET_OTHERS:
@@ -109,7 +108,7 @@ static void vgic_mmio_write_sgir(struct vcpu *source_vcpu,
         return;
     }
 
-    bitmap_for_each ( vcpu_id, &targets, 8 )
+    for_each_set_bit ( vcpu_id, targets )
     {
         struct vcpu *vcpu = d->vcpu[vcpu_id];
         struct vgic_irq *irq = vgic_get_irq(d, vcpu, intid);
--
generated by git-patchbot for /home/xen/git/xen.git#staging