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    Subject[PATCH 4.4 33/90] xen/privcmd: Support correctly 64KB page granularity when mapping memory
    Date
    4.4-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Julien Grall <julien.grall@arm.com>

    commit 753c09b5652bb4fe53e2db648002ec64b32b8827 upstream.

    Commit 5995a68 "xen/privcmd: Add support for Linux 64KB page granularity" did
    not go far enough to support 64KB in mmap_batch_fn.

    The variable 'nr' is the number of 4KB chunk to map. However, when Linux
    is using 64KB page granularity the array of pages (vma->vm_private_data)
    contain one page per 64KB. Fix it by incrementing st->index correctly.

    Furthermore, st->va is not correctly incremented as PAGE_SIZE !=
    XEN_PAGE_SIZE.

    Fixes: 5995a68 ("xen/privcmd: Add support for Linux 64KB page granularity")
    Reported-by: Feng Kan <fkan@apm.com>
    Signed-off-by: Julien Grall <julien.grall@arm.com>
    Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
    Signed-off-by: Juergen Gross <jgross@suse.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/xen/privcmd.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    --- a/drivers/xen/privcmd.c
    +++ b/drivers/xen/privcmd.c
    @@ -335,8 +335,8 @@ static int mmap_batch_fn(void *data, int
    st->global_error = 1;
    }
    }
    - st->va += PAGE_SIZE * nr;
    - st->index += nr;
    + st->va += XEN_PAGE_SIZE * nr;
    + st->index += nr / XEN_PFN_PER_PAGE;

    return 0;
    }

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