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authorDaniel De Graaf <dgdegra@tycho.nsa.gov>2011-03-09 18:07:34 -0500
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-03-16 10:05:36 -0400
commitca47ceaa2c407bbddd395c1807b616042365bd65 (patch)
tree0af54829ad78f6f43cc090299384c294f7739603 /drivers/xen
parentb6f3067985f12d514187059fb10fe3c877f87cb2 (diff)
xen-gntdev: Use ballooned pages for grant mappings
Grant mappings cause the PFN<->MFN mapping to be lost on the pages used for the mapping. Instead of leaking memory, use pages that have already been ballooned out and so have no valid mapping. This removes the need for the bad-page leak workaround as pages are repopulated by the balloon driver. Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/gntdev.c38
1 files changed, 5 insertions, 33 deletions
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index d96d311b858..017ce600fbc 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -36,6 +36,7 @@
#include <xen/xen.h>
#include <xen/grant_table.h>
+#include <xen/balloon.h>
#include <xen/gntdev.h>
#include <xen/events.h>
#include <asm/xen/hypervisor.h>
@@ -122,10 +123,10 @@ static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
NULL == add->pages)
goto err;
+ if (alloc_xenballooned_pages(count, add->pages))
+ goto err;
+
for (i = 0; i < count; i++) {
- add->pages[i] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
- if (add->pages[i] == NULL)
- goto err;
add->map_ops[i].handle = -1;
add->unmap_ops[i].handle = -1;
}
@@ -137,11 +138,6 @@ static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
return add;
err:
- if (add->pages)
- for (i = 0; i < count; i++) {
- if (add->pages[i])
- __free_page(add->pages[i]);
- }
kfree(add->pages);
kfree(add->grants);
kfree(add->map_ops);
@@ -184,8 +180,6 @@ static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
static void gntdev_put_map(struct grant_map *map)
{
- int i;
-
if (!map)
return;
@@ -202,29 +196,7 @@ static void gntdev_put_map(struct grant_map *map)
if (!use_ptemod)
unmap_grant_pages(map, 0, map->count);
- for (i = 0; i < map->count; i++) {
- uint32_t check, *tmp;
- if (!map->pages[i])
- continue;
- /* XXX When unmapping in an HVM domain, Xen will
- * sometimes end up mapping the GFN to an invalid MFN.
- * In this case, writes will be discarded and reads will
- * return all 0xFF bytes. Leak these unusable GFNs
- * until Xen supports fixing their p2m mapping.
- *
- * Confirmed present in Xen 4.1-RC3 with HVM source
- */
- tmp = kmap(map->pages[i]);
- *tmp = 0xdeaddead;
- mb();
- check = *tmp;
- kunmap(map->pages[i]);
- if (check == 0xdeaddead)
- __free_page(map->pages[i]);
- else
- pr_debug("Discard page %d=%ld\n", i,
- page_to_pfn(map->pages[i]));
- }
+ free_xenballooned_pages(map->count, map->pages);
}
kfree(map->pages);
kfree(map->grants);