libxc: reorganize domain builder guest memory allocator

Guest memory allocation in the domain builder of libxc is done via
virtual addresses only. In order to be able to support preallocated
areas not virtually mapped reorganize the memory allocator to keep
track of allocated pages globally and in allocated segments.

This requires an interface change of the allocate callback of the
domain builder which currently is using the last mapped virtual
address as a parameter. This is no problem as the only user of this
callback is stubdom/grub/kexec.c using this virtual address to
calculate the last used pfn.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>

stubdom/grub/kexec.c

@@ -100,9 +100,9 @@ static void do_exchange(struct xc_dom_image *dom, xen_pfn_t target_pfn, xen_pfn_
     dom->p2m_host[target_pfn] = source_mfn;
 }
 
-int kexec_allocate(struct xc_dom_image *dom, xen_vaddr_t up_to)
+int kexec_allocate(struct xc_dom_image *dom)
 {
-    unsigned long new_allocated = (up_to - dom->parms.virt_base) / PAGE_SIZE;
+    unsigned long new_allocated = dom->pfn_alloc_end - dom->rambase_pfn;
     unsigned long i;
 
     pages = realloc(pages, new_allocated * sizeof(*pages));
@@ -319,8 +319,6 @@ void kexec(void *kernel, long kernel_size, void *module, long module_size, char
 
     /* Make sure the bootstrap page table does not RW-map any of our current
      * page table frames */
-    kexec_allocate(dom, dom->virt_pgtab_end);
-
     if ( (rc = xc_dom_update_guest_p2m(dom))) {
         grub_printf("xc_dom_update_guest_p2m returned %d\n", rc);
         errnum = ERR_BOOT_FAILURE;