x86/apic: remove vector_allocation_cpumask hook

All implementations use the same hook which is a wrapper around
cpumask_of(cpu).  Adjust callers to no longer use such dummy mask with a
single CPU set, as the CPU is already known to the caller.  This removes a
pair of usages of for_each_cpu().

No functional change intended.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

xen/arch/x86/genapic/bigsmp.c

@@ -47,7 +47,6 @@ static int __init cf_check probe_bigsmp(void)
 const struct genapic __initconst_cf_clobber apic_bigsmp = {
 	APIC_INIT("bigsmp", probe_bigsmp),
 	.init_apic_ldr = init_apic_ldr_phys,
-	.vector_allocation_cpumask = vector_allocation_cpumask_phys,
 	.send_IPI_mask = send_IPI_mask_phys,
 	.send_IPI_self = send_IPI_self_legacy
 };

xen/arch/x86/genapic/default.c

@@ -17,7 +17,6 @@
 const struct genapic __initconst_cf_clobber apic_default = {
 	APIC_INIT("default", NULL),
 	.init_apic_ldr = init_apic_ldr_flat,
-	.vector_allocation_cpumask = vector_allocation_cpumask_phys,
 	.send_IPI_mask = send_IPI_mask_flat,
 	.send_IPI_self = send_IPI_self_legacy
 };

xen/arch/x86/genapic/delivery.c

@@ -30,11 +30,6 @@ void cf_check init_apic_ldr_phys(void)
 	/* We only deliver in phys mode - no setup needed. */
 }
 
-const cpumask_t *cf_check vector_allocation_cpumask_phys(int cpu)
-{
-	return cpumask_of(cpu);
-}
-
 unsigned int cpu_mask_to_apicid(const cpumask_t *cpumask)
 {
 	/* As we are using single CPU as destination, pick only one CPU here */

xen/arch/x86/genapic/x2apic.c

@@ -141,7 +141,6 @@ static void cf_check send_IPI_mask_x2apic_cluster(
 static const struct genapic __initconst_cf_clobber apic_x2apic_phys = {
     APIC_INIT("x2apic_phys", NULL),
     .init_apic_ldr = init_apic_ldr_phys,
-    .vector_allocation_cpumask = vector_allocation_cpumask_phys,
     .send_IPI_mask = send_IPI_mask_x2apic_phys,
     .send_IPI_self = send_IPI_self_x2apic
 };
@@ -156,12 +155,6 @@ static const struct genapic __initconst_cf_clobber apic_x2apic_phys = {
 static const struct genapic __initconst_cf_clobber apic_x2apic_mixed = {
     APIC_INIT("x2apic_mixed", NULL),
 
-    /*
-     * The following fields are exclusively used by external interrupts and
-     * hence are set to use Physical destination mode handlers.
-     */
-    .vector_allocation_cpumask = vector_allocation_cpumask_phys,
-
     /*
      * The following fields are exclusively used by IPIs and hence are set to
      * use Cluster Logical destination mode handlers.  Note that init_apic_ldr

xen/arch/x86/include/asm/genapic.h

@@ -24,7 +24,6 @@ struct genapic {
 	int (*probe)(void);
 
 	void (*init_apic_ldr)(void);
-	const cpumask_t *(*vector_allocation_cpumask)(int cpu);
 	void (*send_IPI_mask)(const cpumask_t *mask, int vector);
     void (*send_IPI_self)(uint8_t vector);
 };
@@ -35,8 +34,6 @@ struct genapic {
 
 #define TARGET_CPUS ((const typeof(cpu_online_map) *)&cpu_online_map)
 #define init_apic_ldr() alternative_vcall(genapic.init_apic_ldr)
-#define vector_allocation_cpumask(cpu) \
-	alternative_call(genapic.vector_allocation_cpumask, cpu)
 
 extern struct genapic genapic;
 extern const struct genapic apic_default;
@@ -50,7 +47,6 @@ void cf_check send_IPI_mask_flat(const cpumask_t *cpumask, int vector);
 void cf_check init_apic_ldr_phys(void);
 unsigned int cpu_mask_to_apicid(const cpumask_t *cpumask);
 void cf_check send_IPI_mask_phys(const cpumask_t *mask, int vector);
-const cpumask_t *cf_check vector_allocation_cpumask_phys(int cpu);
 
 void generic_apic_probe(void);
 void generic_bigsmp_probe(void);

xen/arch/x86/irq.c

@@ -621,16 +621,12 @@ static int _assign_irq_vector(struct irq_desc *desc, const cpumask_t *mask)
 
     for_each_cpu(cpu, mask)
     {
-        const cpumask_t *vec_mask;
-        int new_cpu;
         int vector, offset;
 
         /* Only try and allocate irqs on cpus that are present. */
         if (!cpu_online(cpu))
             continue;
 
-        vec_mask = vector_allocation_cpumask(cpu);
-
         vector = current_vector;
         offset = current_offset;
 next:
@@ -650,13 +646,13 @@ next:
             && test_bit(vector, irq_used_vectors) )
             goto next;
 
-        if ( cpumask_test_cpu(0, vec_mask) &&
+        if ( !cpu &&
              vector >= FIRST_LEGACY_VECTOR && vector <= LAST_LEGACY_VECTOR )
             goto next;
 
-        for_each_cpu(new_cpu, vec_mask)
-            if (per_cpu(vector_irq, new_cpu)[vector] >= 0)
+        if ( per_cpu(vector_irq, cpu)[vector] >= 0 )
             goto next;
+
         /* Found one! */
         current_vector = vector;
         current_offset = offset;
@@ -688,12 +684,11 @@ next:
                 release_old_vec(desc);
         }
 
-        trace_irq_mask(TRC_HW_IRQ_ASSIGN_VECTOR, irq, vector, vec_mask);
+        trace_irq_mask(TRC_HW_IRQ_ASSIGN_VECTOR, irq, vector, cpumask_of(cpu));
 
-        for_each_cpu(new_cpu, vec_mask)
-            per_cpu(vector_irq, new_cpu)[vector] = irq;
+        per_cpu(vector_irq, cpu)[vector] = irq;
         desc->arch.vector = vector;
-        cpumask_copy(desc->arch.cpu_mask, vec_mask);
+        cpumask_copy(desc->arch.cpu_mask, cpumask_of(cpu));
 
         desc->arch.used = IRQ_USED;
         ASSERT((desc->arch.used_vectors == NULL)