hw/arm/virt: Introduce variable region_base in virt_set_high_memmap()

This introduces variable 'region_base' for the base address of the
specific high memory region. It's the preparatory work to optimize
high memory region address assignment.

No functional change intended.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Tested-by: Zhenyu Zhang <zhenyzha@redhat.com>
Message-id: 20221029224307.138822-4-gshan@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/arm/virt.c

@@ -1693,15 +1693,15 @@ static uint64_t virt_cpu_mp_affinity(VirtMachineState *vms, int idx)
 static void virt_set_high_memmap(VirtMachineState *vms,
                                  hwaddr base, int pa_bits)
 {
-    hwaddr region_size;
+    hwaddr region_base, region_size;
     bool fits;
     int i;
 
     for (i = VIRT_LOWMEMMAP_LAST; i < ARRAY_SIZE(extended_memmap); i++) {
+        region_base = ROUND_UP(base, extended_memmap[i].size);
         region_size = extended_memmap[i].size;
 
-        base = ROUND_UP(base, region_size);
-        vms->memmap[i].base = base;
+        vms->memmap[i].base = region_base;
         vms->memmap[i].size = region_size;
 
         /*
@@ -1710,9 +1710,9 @@ static void virt_set_high_memmap(VirtMachineState *vms,
          *
          * For each device that doesn't fit, disable it.
          */
-        fits = (base + region_size) <= BIT_ULL(pa_bits);
+        fits = (region_base + region_size) <= BIT_ULL(pa_bits);
         if (fits) {
-            vms->highest_gpa = base + region_size - 1;
+            vms->highest_gpa = region_base + region_size - 1;
         }
 
         switch (i) {
@@ -1727,7 +1727,7 @@ static void virt_set_high_memmap(VirtMachineState *vms,
             break;
         }
 
-        base += region_size;
+        base = region_base + region_size;
     }
 }