Pages returned by alloc_xenballooned_pages() will be used for grant
mapping which will call set_phys_to_machine() (in PV guests).
Ballooned pages are set as INVALID_P2M_ENTRY in the p2m and thus may
be using the (shared) missing tables and a subsequent
set_phys_to_machine() will need to allocate new tables.
Since the grant mapping may be done from a context that cannot sleep,
the p2m entries must already be allocated.
Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
---
drivers/xen/balloon.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 3094f38f..e040cf4 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -593,6 +593,7 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages)
{
int pgno = 0;
struct page *page;
+ int ret = -ENOMEM;
mutex_lock(&balloon_mutex);
@@ -602,6 +603,11 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages)
page = balloon_retrieve(true);
if (page) {
pages[pgno++] = page;
+#ifdef CONFIG_XEN_HAVE_PVMMU
+ ret = xen_alloc_p2m_entry(page_to_pfn(page));
+ if (ret < 0)
+ goto out_undo;
+#endif
} else {
ret = add_ballooned_pages(nr_pages - pgno);
if (ret < 0)
@@ -613,7 +619,7 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages)
out_undo:
mutex_unlock(&balloon_mutex);
free_xenballooned_pages(pgno, pages);
- return -ENOMEM;
+ return ret;
}
EXPORT_SYMBOL(alloc_xenballooned_pages);
--
2.1.4
--
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