path: root/main/xen/xsa214.patch
diff options
Diffstat (limited to 'main/xen/xsa214.patch')
1 files changed, 0 insertions, 41 deletions
diff --git a/main/xen/xsa214.patch b/main/xen/xsa214.patch
deleted file mode 100644
index 46a3d3a4c6..0000000000
--- a/main/xen/xsa214.patch
+++ /dev/null
@@ -1,41 +0,0 @@
-From: Jan Beulich <jbeulich@suse.com>
-Subject: x86: discard type information when stealing pages
-While a page having just a single general reference left necessarily
-has a zero type reference count too, its type may still be valid (and
-in validated state; at present this is only possible and relevant for
-PGT_seg_desc_page, as page tables have their type forcibly zapped when
-their type reference count drops to zero, and
-PGT_{writable,shared}_page pages don't require any validation). In
-such a case when the page is being re-used with the same type again,
-validation is being skipped. As validation criteria differ between
-32- and 64-bit guests, pages to be transferred between guests need to
-have their validation indicator zapped (and with it we zap all other
-type information at once).
-This is XSA-214.
-Reported-by: Jann Horn <jannh@google.com>
-Signed-off-by: Jan Beulich <jbeulich@suse.com>
-Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---- a/xen/arch/x86/mm.c
-+++ b/xen/arch/x86/mm.c
-@@ -4466,6 +4466,17 @@ int steal_page(
- y = cmpxchg(&page->count_info, x, x & ~PGC_count_mask);
- } while ( y != x );
-+ /*
-+ * With the sole reference dropped temporarily, no-one can update type
-+ * information. Type count also needs to be zero in this case, but e.g.
-+ * PGT_seg_desc_page may still have PGT_validated set, which we need to
-+ * clear before transferring ownership (as validation criteria vary
-+ * depending on domain type).
-+ */
-+ BUG_ON(page->u.inuse.type_info & (PGT_count_mask | PGT_locked |
-+ PGT_pinned));
-+ page->u.inuse.type_info = 0;
- /* Swizzle the owner then reinstate the PGC_allocated reference. */
- page_set_owner(page, NULL);
- y = page->count_info;