[PATCH v7 03/17] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn

Shannon Zhao
2016-03-24T14:51:49Z

Make xen_xlate_map_ballooned_pages work with 64K pages. In that case
Kernel pages are 64K in size but Xen pages remain 4K in size. Xen pfns
refer to 4K pages.

Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
drivers/xen/xlate_mmu.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
index 9692656..28f728b 100644
--- a/drivers/xen/xlate_mmu.c
+++ b/drivers/xen/xlate_mmu.c
@@ -207,9 +207,12 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
void *vaddr;
int rc;
unsigned int i;
+ unsigned long nr_pages;
+ xen_pfn_t xen_pfn = 0;

BUG_ON(nr_grant_frames == 0);
- pages = kcalloc(nr_grant_frames, sizeof(pages[0]), GFP_KERNEL);
+ nr_pages = DIV_ROUND_UP(nr_grant_frames, XEN_PFN_PER_PAGE);
+ pages = kcalloc(nr_pages, sizeof(pages[0]), GFP_KERNEL);
if (!pages)
return -ENOMEM;

@@ -218,22 +221,25 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
kfree(pages);
return -ENOMEM;
}
- rc = alloc_xenballooned_pages(nr_grant_frames, pages);
+ rc = alloc_xenballooned_pages(nr_pages, pages);
if (rc) {
- pr_warn("%s Couldn't balloon alloc %ld pfns rc:%d\n", __func__,
- nr_grant_frames, rc);
+ pr_warn("%s Couldn't balloon alloc %ld pages rc:%d\n", __func__,
+ nr_pages, rc);
kfree(pages);
kfree(pfns);
return rc;
}
- for (i = 0; i < nr_grant_frames; i++)
- pfns[i] = page_to_pfn(pages[i]);
+ for (i = 0; i < nr_grant_frames; i++) {
+ if ((i % XEN_PFN_PER_PAGE) == 0)
+ xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
+ pfns[i] = pfn_to_gfn(xen_pfn++);
+ }

- vaddr = vmap(pages, nr_grant_frames, 0, PAGE_KERNEL);
+ vaddr = vmap(pages, nr_pages, 0, PAGE_KERNEL);
if (!vaddr) {
- pr_warn("%s Couldn't map %ld pfns rc:%d\n", __func__,
- nr_grant_frames, rc);
- free_xenballooned_pages(nr_grant_frames, pages);
+ pr_warn("%s Couldn't map %ld pages rc:%d\n", __func__,
+ nr_pages, rc);
+ free_xenballooned_pages(nr_pages, pages);
kfree(pages);
kfree(pfns);
return -ENOMEM;
--
2.1.4