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

[Shannon Zhao <shannon.zhao@xxxxxxxxxx>]

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


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