[21/63] xen: set max_pfn_mapped to the last pfn mapped

From: Greg KH
Date: Fri Mar 25 2011 - 19:52:38 EST


2.6.38-stable review patch. If anyone has any objections, please let us know.

------------------

From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

commit 14988a4d350ce3b41ecad4f63c4f44c56f5ae34d upstream.

Do not set max_pfn_mapped to the end of the initial memory mappings,
that also contain pages that don't belong in pfn space (like the mfn
list).

Set max_pfn_mapped to the last real pfn mapped in the initial memory
mappings that is the pfn backing _end.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
LKML-Reference: <alpine.DEB.2.00.1103171739050.3382@kaball-desktop>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
arch/x86/xen/mmu.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1651,9 +1651,6 @@ static __init void xen_map_identity_earl
for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
pte_t pte;

- if (pfn > max_pfn_mapped)
- max_pfn_mapped = pfn;
-
if (!pte_none(pte_page[pteidx]))
continue;

@@ -1711,6 +1708,12 @@ __init pgd_t *xen_setup_kernel_pagetable
pud_t *l3;
pmd_t *l2;

+ /* max_pfn_mapped is the last pfn mapped in the initial memory
+ * mappings. Considering that on Xen after the kernel mappings we
+ * have the mappings of some pages that don't exist in pfn space, we
+ * set max_pfn_mapped to the last real pfn mapped. */
+ max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
+
/* Zap identity mapping */
init_level4_pgt[0] = __pgd(0);

@@ -1815,9 +1818,7 @@ __init pgd_t *xen_setup_kernel_pagetable
initial_kernel_pmd =
extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);

- max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
- xen_start_info->nr_pt_frames * PAGE_SIZE +
- 512*1024);
+ max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));

kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
memcpy(initial_kernel_pmd, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);


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