xen/arm: vgic: Correctly calculate GICD_TYPER.ITLinesNumber

The formula of GICD_TYPER.ITLinesNumber is 32(N + 1).

As the number of SPIs suppported by the domain may not be a multiple of
32, we have to round up the number before using it.

At the same time remove the mask GICD_TYPE_LINES which is pointless.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

xen/arch/arm/vgic-v2.c

@@ -55,7 +55,7 @@ static int vgic_v2_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         /* No secure world support for guests. */
         vgic_lock(v);
         *r = ( ((v->domain->max_vcpus - 1) << GICD_TYPE_CPUS_SHIFT) )
-            |( ((v->domain->arch.vgic.nr_spis / 32)) & GICD_TYPE_LINES );
+            | DIV_ROUND_UP(v->domain->arch.vgic.nr_spis, 32);
         vgic_unlock(v);
         return 1;
     case GICD_IIDR:

xen/arch/arm/vgic-v3.c

@@ -700,7 +700,7 @@ static int vgic_v3_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         if ( dabt.size != DABT_WORD ) goto bad_width;
         /* No secure world support for guests. */
         *r = ((ncpus - 1) << GICD_TYPE_CPUS_SHIFT |
-              ((v->domain->arch.vgic.nr_spis / 32) & GICD_TYPE_LINES));
+              DIV_ROUND_UP(v->domain->arch.vgic.nr_spis, 32));
 
         *r |= (irq_bits - 1) << GICD_TYPE_ID_BITS_SHIFT;