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authorDavid Vrabel <david.vrabel@citrix.com>2015-07-22 14:50:37 +0100
committerDavid Vrabel <david.vrabel@citrix.com>2015-10-23 14:20:31 +0100
commit4a69c909deb0dd3cae653d14ac0ff52d5440a19c (patch)
tree13c9a6a80d575d706e8b689604047d0591ffad91 /drivers/xen
parent8edfcf882eb91ec9028c7334f90f6ef3db5b0fcf (diff)
downloadlinux-4a69c909deb0dd3cae653d14ac0ff52d5440a19c.tar.gz
xen/balloon: pre-allocate p2m entries for ballooned pages
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@citrix.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/balloon.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 25fd1bd949d8..f56662324a47 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -602,6 +602,11 @@ 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)