xen/setup: Don't relocate p2m over existing one

When relocating the p2m, take special care not to relocate it so
that is overlaps with the current location of the p2m/initrd. This is
needed since the full extent of the current location is not marked as a
reserved region in the e820.

This was seen to happen to a dom0 with a large initial p2m and a small
reserved region in the middle of the initial p2m.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
OraBug: 25497392

(cherry picked from commit 7ecec8503af37de6be4f96b53828d640a968705f)
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index e4f88de6f40fc3d767679bf7496b76d828030e5f..2eda84116168fd197ba3a10d41a91b3de26c75b5 100644 (file)
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -713,10 +713,9 @@ static void __init xen_reserve_xen_mfnlist(void)
                size = PFN_PHYS(xen_start_info->nr_p2m_frames);
        }
 
-       if (!xen_is_e820_reserved(start, size)) {
-               memblock_reserve(start, size);
+       memblock_reserve(start, size);
+       if (!xen_is_e820_reserved(start, size))
                return;
-       }
 
 #ifdef CONFIG_X86_32
        /*
@@ -727,6 +726,7 @@ static void __init xen_reserve_xen_mfnlist(void)
        BUG();
 #else
        xen_relocate_p2m();
+       memblock_free(start, size);
 #endif
 }