[PATCH v10 03/17] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn

From: Shannon Zhao
Date: Fri Apr 01 2016 - 11:50:13 EST


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@xxxxxxxxxx>
Reviewed-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
drivers/xen/xlate_mmu.c | 38 +++++++++++++++++++++++++++-----------
1 file changed, 27 insertions(+), 11 deletions(-)

diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
index 9692656..23f1387 100644
--- a/drivers/xen/xlate_mmu.c
+++ b/drivers/xen/xlate_mmu.c
@@ -189,6 +189,18 @@ int xen_xlate_unmap_gfn_range(struct vm_area_struct *vma,
}
EXPORT_SYMBOL_GPL(xen_xlate_unmap_gfn_range);

+struct map_balloon_pages {
+ xen_pfn_t *pfns;
+ unsigned int idx;
+};
+
+static void setup_balloon_gfn(unsigned long gfn, void *data)
+{
+ struct map_balloon_pages *info = data;
+
+ info->pfns[info->idx++] = gfn;
+}
+
/**
* xen_xlate_map_ballooned_pages - map a new set of ballooned pages
* @gfns: returns the array of corresponding GFNs
@@ -205,11 +217,13 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt,
struct page **pages;
xen_pfn_t *pfns;
void *vaddr;
+ struct map_balloon_pages data;
int rc;
- unsigned int i;
+ unsigned long nr_pages;

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 +232,24 @@ 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]);

- vaddr = vmap(pages, nr_grant_frames, 0, PAGE_KERNEL);
+ data.pfns = pfns;
+ data.idx = 0;
+ xen_for_each_gfn(pages, nr_grant_frames, setup_balloon_gfn, &data);
+
+ 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