xen/mmu: If the revector fails, don't attempt to revector anything else.

If the P2M revectoring would fail, we would try to continue on by
cleaning the PMD for L1 (PTE) page-tables. The xen_cleanhighmap
is greedy and erases the PMD on both boundaries. Since the P2M
array can share the PMD, we would wipe out part of the __ka
that is still used in the P2M tree to point to P2M leafs.

This fixes it by bypassing the revectoring and continuing on.
If the revector fails, a nice WARN is printed so we can still
troubleshoot this.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 5b2cb54425ce..cb9db72b33f8 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1238,7 +1238,8 @@ static void __init xen_pagetable_setup_done(pgd_t *base)
                         memblock_free(__pa(xen_start_info->mfn_list), size);
                         /* And revector! Bye bye old array */
                         xen_start_info->mfn_list = new_mfn_list;
-                }
+                } else
+                        goto skip;
         }
         /* At this stage, cleanup_highmap has already cleaned __ka space
          * from _brk_limit way up to the max_pfn_mapped (which is the end of
@@ -1259,6 +1260,7 @@ static void __init xen_pagetable_setup_done(pgd_t *base)
          * anything at this stage. */
         xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1);
 #endif
+skip:
 #endif
         xen_post_allocator_init();
 }