[Xen-changelog] [xen master] xen/arm: p2m: apply_p2m_changes: Do not undo more than necessary

[patchbot@xxxxxxx]

commit b13981ff7a5e57798b8dd802c9ee3ba79914e75b
Author:     Julien Grall <julien.grall@xxxxxxx>
AuthorDate: Fri May 20 14:37:41 2016 +0100
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Sat May 21 16:16:46 2016 +0100

    xen/arm: p2m: apply_p2m_changes: Do not undo more than necessary
    
    Since commit 4b25423a "arch/arm: unmap partially-mapped memory regions",
    Xen has been undoing the P2M mappings when an error occurred during
    insertion or memory allocation.
    
    The function apply_p2m_changes can work with region not-aligned to a
    block size (2MB, 1G) or page size (4K). The mapping will be done by
    splitting the region in a set of regions aligned to the size supported
    by the page table.
    
    The mapping of a region could fail when it is not possible to allocate
    memory for an intermediate table (i.e a new or when shattering a block).
    
    When the mapping is undone, the end of the region is computed using the
    base address of the current region and the size of the failing level.
    However the failing level may not be the leaf one, therefore unrelated
    entries will be removed.
    
    Fix it by removing the mapping from the start address up to the last
    region that has been successfully mapped.
    
    Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
    Reviewed-by: Wei Chen <Wei.Chen@xxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
---
 xen/arch/arm/p2m.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index db21433..68c67b0 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -1189,13 +1189,10 @@ out:
     {
         BUG_ON(addr == end_gpaddr);
         /*
-         * addr keeps the address of the last successfully-inserted mapping,
-         * while apply_p2m_changes() considers an address range which is
-         * exclusive of end_gpaddr: add level_size to addr to obtain the
-         * right end of the range
+         * addr keeps the address of the end of the last successfully-inserted
+         * mapping.
          */
-        apply_p2m_changes(d, REMOVE,
-                          start_gpaddr, addr + level_sizes[level], orig_maddr,
+        apply_p2m_changes(d, REMOVE, start_gpaddr, addr, orig_maddr,
                           mattr, 0, p2m_invalid, d->arch.p2m.default_access);
     }
 
--
generated by git-patchbot for /home/xen/git/xen.git#master

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