xen/arm: vgic: Use 'unsigned int' rather than 'int' whenever it is possible

Switch to unsigned int for the return/parameters of the following
functions:
    * REG_RANK_NR(): 'b' (number of bits) and the return is always positive.
      'n' doesn't need to be size specific.
    * vgic_rank_offset(): 'b' (number of bits), 'n' (register index),
      's' (size of the access) are always positive.
    * vgic_{enable, disable}_irqs(): 'n' (rank index) is always positive
    * vgic_get_virq_type(): 'n' (rank index) and 'index' (register
      index) are always positive.
    * vgic_get_rank(): 'rank' is an index and therefore always positive.

Take the opportunity to propogate the unsignedness to the local
variable used for the arguments.

This will remove some of the warning reported by GCC 12.2.1 when
passing the flags -Wsign-conversion/-Wconversion.

Signed-off-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Henry Wang <Henry.Wang@arm.com>
Tested-by: Henry Wang <Henry.Wang@arm.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>

xen/arch/arm/include/asm/vgic.h

@@ -252,7 +252,7 @@ struct vgic_ops {
  * Rank containing GICD_<FOO><n> for GICD_<FOO> with
  * <b>-bits-per-interrupt
  */
-static inline int REG_RANK_NR(int b, uint32_t n)
+static inline unsigned int REG_RANK_NR(unsigned int b, unsigned int n)
 {
     switch ( b )
     {
@@ -297,10 +297,13 @@ extern void gic_remove_from_lr_pending(struct vcpu *v, struct pending_irq *p);
 extern void vgic_init_pending_irq(struct pending_irq *p, unsigned int virq);
 extern struct pending_irq *irq_to_pending(struct vcpu *v, unsigned int irq);
 extern struct pending_irq *spi_to_pending(struct domain *d, unsigned int irq);
-extern struct vgic_irq_rank *vgic_rank_offset(struct vcpu *v, int b, int n, int s);
+extern struct vgic_irq_rank *vgic_rank_offset(struct vcpu *v,
+                                              unsigned int b,
+                                              unsigned int n,
+                                              unsigned int s);
 extern struct vgic_irq_rank *vgic_rank_irq(struct vcpu *v, unsigned int irq);
-extern void vgic_disable_irqs(struct vcpu *v, uint32_t r, int n);
-extern void vgic_enable_irqs(struct vcpu *v, uint32_t r, int n);
+extern void vgic_disable_irqs(struct vcpu *v, uint32_t r, unsigned int n);
+extern void vgic_enable_irqs(struct vcpu *v, uint32_t r, unsigned int n);
 extern void vgic_set_irqs_pending(struct vcpu *v, uint32_t r,
                                   unsigned int rank);
 extern void register_vgic_ops(struct domain *d, const struct vgic_ops *ops);

xen/arch/arm/vgic-v2.c

@@ -161,7 +161,11 @@ static int vgic_v2_distr_mmio_read(struct vcpu *v, mmio_info_t *info,
 {
     struct hsr_dabt dabt = info->dabt;
     struct vgic_irq_rank *rank;
-    int gicd_reg = (int)(info->gpa - v->domain->arch.vgic.dbase);
+    /*
+     * gpa/dbase are paddr_t which size may be higher than 32-bit. Yet
+     * the difference will always be smaller than 32-bit.
+     */
+    unsigned int gicd_reg = info->gpa - v->domain->arch.vgic.dbase;
     unsigned long flags;
 
     perfc_incr(vgicd_reads);
@@ -403,7 +407,11 @@ static int vgic_v2_distr_mmio_write(struct vcpu *v, mmio_info_t *info,
 {
     struct hsr_dabt dabt = info->dabt;
     struct vgic_irq_rank *rank;
-    int gicd_reg = (int)(info->gpa - v->domain->arch.vgic.dbase);
+    /*
+     * gpa/dbase are paddr_t which size may be higher than 32-bit. Yet
+     * the difference will always be smaller than 32-bit.
+     */
+    unsigned int gicd_reg = info->gpa - v->domain->arch.vgic.dbase;
     uint32_t tr;
     unsigned long flags;
 

xen/arch/arm/vgic.c

@@ -24,7 +24,8 @@
 #include <asm/gic.h>
 #include <asm/vgic.h>
 
-static inline struct vgic_irq_rank *vgic_get_rank(struct vcpu *v, int rank)
+static inline struct vgic_irq_rank *vgic_get_rank(struct vcpu *v,
+                                                  unsigned int rank)
 {
     if ( rank == 0 )
         return v->arch.vgic.private_irqs;
@@ -38,17 +39,17 @@ static inline struct vgic_irq_rank *vgic_get_rank(struct vcpu *v, int rank)
  * Returns rank corresponding to a GICD_<FOO><n> register for
  * GICD_<FOO> with <b>-bits-per-interrupt.
  */
-struct vgic_irq_rank *vgic_rank_offset(struct vcpu *v, int b, int n,
-                                              int s)
+struct vgic_irq_rank *vgic_rank_offset(struct vcpu *v, unsigned int b,
+                                       unsigned int n, unsigned int s)
 {
-    int rank = REG_RANK_NR(b, (n >> s));
+    unsigned int rank = REG_RANK_NR(b, (n >> s));
 
     return vgic_get_rank(v, rank);
 }
 
 struct vgic_irq_rank *vgic_rank_irq(struct vcpu *v, unsigned int irq)
 {
-    int rank = irq/32;
+    unsigned int rank = irq / 32;
 
     return vgic_get_rank(v, rank);
 }
@@ -324,14 +325,14 @@ void arch_move_irqs(struct vcpu *v)
     }
 }
 
-void vgic_disable_irqs(struct vcpu *v, uint32_t r, int n)
+void vgic_disable_irqs(struct vcpu *v, uint32_t r, unsigned int n)
 {
     const unsigned long mask = r;
     struct pending_irq *p;
     struct irq_desc *desc;
     unsigned int irq;
     unsigned long flags;
-    int i = 0;
+    unsigned int i = 0;
     struct vcpu *v_target;
 
     /* LPIs will never be disabled via this function. */
@@ -361,7 +362,9 @@ void vgic_disable_irqs(struct vcpu *v, uint32_t r, int n)
 #define VGIC_ICFG_MASK(intr) (1U << ((2 * ((intr) % 16)) + 1))
 
 /* The function should be called with the rank lock taken */
-static inline unsigned int vgic_get_virq_type(struct vcpu *v, int n, int index)
+static inline unsigned int vgic_get_virq_type(struct vcpu *v,
+                                              unsigned int n,
+                                              unsigned int index)
 {
     struct vgic_irq_rank *r = vgic_get_rank(v, n);
     uint32_t tr = r->icfg[index >> 4];
@@ -374,13 +377,13 @@ static inline unsigned int vgic_get_virq_type(struct vcpu *v, int n, int index)
         return IRQ_TYPE_LEVEL_HIGH;
 }
 
-void vgic_enable_irqs(struct vcpu *v, uint32_t r, int n)
+void vgic_enable_irqs(struct vcpu *v, uint32_t r, unsigned int n)
 {
     const unsigned long mask = r;
     struct pending_irq *p;
     unsigned int irq;
     unsigned long flags;
-    int i = 0;
+    unsigned int i = 0;
     struct vcpu *v_target;
     struct domain *d = v->domain;