Hi David,
On 24/07/2015 12:47, David Vrabel wrote:
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 fd6970f3..8932d10 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -541,6 +541,7 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages)
{
int pgno = 0;
struct page *page;
+ int ret = -ENOMEM;
mutex_lock(&balloon_mutex);
@@ -550,6 +551,11 @@ 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));
Don't you want to call this function only when the guest is not using
auto-translated physmap?
+ if (ret < 0)
+ goto out_undo;
+#endif
} else {
enum bp_state st;
@@ -576,7 +582,7 @@ 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);
Regards,
--
Julien Grall
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