Hi Shannon,
On 30/03/16 08:38, Shannon Zhao wrote:
On 2016/3/30 0:28, Julien Grall wrote:
On 24/03/16 14:44, Shannon Zhao wrote:
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 | 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++);
+ }
Would it be possible to re-use xen_for_each_gfn? This will avoid
open-coding the loop to break down the Linux page.
I don't think so. Using xen_acpi_guest_init will require factoring
"pfns[i] = pfn_to_gfn(xen_pfn++)" to a function with parameter pfns[i].
How can we pass pfns[i]?
By using the variable data. Something along those lines:
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;
data->pfns[data->idx] = gfn;
data->idx++;
}
And then in xen_xlate_map_ballooned_pages
xen_for_each_gfn(pages, nr_grant_frames, setup_balloon_gfn, &data);
Regards,
--
Julien Grall
--
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