xen: dynamically allocate p2m space
Use early brk mechanism to allocate p2m tables, to save memory when
booting non-Xen.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 42086ac..ecbdcf0 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -174,18 +174,16 @@
#define TOP_ENTRIES (MAX_DOMAIN_PAGES / P2M_ENTRIES_PER_PAGE)
/* Placeholder for holes in the address space */
-static unsigned long p2m_missing[P2M_ENTRIES_PER_PAGE] __page_aligned_data =
- { [ 0 ... P2M_ENTRIES_PER_PAGE-1 ] = ~0UL };
+static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_ENTRIES_PER_PAGE);
/* Array of pointers to pages containing p2m entries */
-static unsigned long *p2m_top[TOP_ENTRIES] __page_aligned_data =
- { [ 0 ... TOP_ENTRIES - 1] = &p2m_missing[0] };
+static RESERVE_BRK_ARRAY(unsigned long *, p2m_top, TOP_ENTRIES);
/* Arrays of p2m arrays expressed in mfns used for save/restore */
-static unsigned long p2m_top_mfn[TOP_ENTRIES] __page_aligned_bss;
+static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, TOP_ENTRIES);
-static unsigned long p2m_top_mfn_list[TOP_ENTRIES / P2M_ENTRIES_PER_PAGE]
- __page_aligned_bss;
+static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn_list,
+ (TOP_ENTRIES / P2M_ENTRIES_PER_PAGE));
static inline unsigned p2m_top_index(unsigned long pfn)
{
@@ -209,7 +207,7 @@
p2m_top_mfn[topidx] = virt_to_mfn(p2m_top[topidx]);
}
- for (idx = 0; idx < ARRAY_SIZE(p2m_top_mfn_list); idx++) {
+ for (idx = 0; idx < TOP_ENTRIES/P2M_ENTRIES_PER_PAGE; idx++) {
unsigned topidx = idx * P2M_ENTRIES_PER_PAGE;
p2m_top_mfn_list[idx] = virt_to_mfn(&p2m_top_mfn[topidx]);
}
@@ -230,6 +228,22 @@
unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list;
unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
unsigned pfn;
+ unsigned i;
+
+ p2m_missing = extend_brk(sizeof(*p2m_missing) * P2M_ENTRIES_PER_PAGE,
+ PAGE_SIZE);
+ for (i = 0; i < P2M_ENTRIES_PER_PAGE; i++)
+ p2m_missing[i] = ~0UL;
+
+ p2m_top = extend_brk(sizeof(*p2m_top) * TOP_ENTRIES,
+ PAGE_SIZE);
+ for (i = 0; i < TOP_ENTRIES; i++)
+ p2m_top[i] = p2m_missing;
+
+ p2m_top_mfn = extend_brk(sizeof(*p2m_top_mfn) * TOP_ENTRIES, PAGE_SIZE);
+ p2m_top_mfn_list = extend_brk(sizeof(*p2m_top_mfn_list) *
+ (TOP_ENTRIES / P2M_ENTRIES_PER_PAGE),
+ PAGE_SIZE);
for (pfn = 0; pfn < max_pfn; pfn += P2M_ENTRIES_PER_PAGE) {
unsigned topidx = p2m_top_index(pfn);