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[Xen-changelog] [xen master] libxc: introduce xc_dom_seg_to_ptr_pages

commit 53bfcf585b09eb4ac2240f89d1ade77421cd2451
Author:     Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
AuthorDate: Fri Jun 14 16:39:34 2013 +0100
Commit:     Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CommitDate: Fri Jun 14 16:39:34 2013 +0100

    libxc: introduce xc_dom_seg_to_ptr_pages
    Provide a version of xc_dom_seg_to_ptr which returns the number of
    guest pages it has actually mapped.  This is useful for callers who
    want to do range checking; we will use this later in this series.
    This is part of the fix to a security issue, XSA-55.
    Signed-off-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
    Reviewed-by: Chuck Anderson <chuck.anderson@xxxxxxxxxx>
    v7: xc_dom_seg_to_ptr_pages now always expects pages_out!=NULL.
       (It seems silly to have it tolerate NULL when all the real callers
        pass non-NULL and there's a version which doesn't need pages_out
        anyway.  Fix the call in xc_dom_seg_to_ptr to have a dummy pages
        for pages_out.)
    v5: xc_dom_seg_to_ptr_pages sets *pages_out=0 if it returns NULL.
    v4 was:
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
 tools/libxc/xc_dom.h |   19 ++++++++++++++++---
 1 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/tools/libxc/xc_dom.h b/tools/libxc/xc_dom.h
index ac36600..316c5cb 100644
--- a/tools/libxc/xc_dom.h
+++ b/tools/libxc/xc_dom.h
@@ -294,14 +294,27 @@ void *xc_dom_pfn_to_ptr(struct xc_dom_image *dom, 
xen_pfn_t first,
 void xc_dom_unmap_one(struct xc_dom_image *dom, xen_pfn_t pfn);
 void xc_dom_unmap_all(struct xc_dom_image *dom);
-static inline void *xc_dom_seg_to_ptr(struct xc_dom_image *dom,
-                                      struct xc_dom_seg *seg)
+static inline void *xc_dom_seg_to_ptr_pages(struct xc_dom_image *dom,
+                                      struct xc_dom_seg *seg,
+                                      xen_pfn_t *pages_out)
     xen_vaddr_t segsize = seg->vend - seg->vstart;
     unsigned int page_size = XC_DOM_PAGE_SIZE(dom);
     xen_pfn_t pages = (segsize + page_size - 1) / page_size;
+    void *retval;
+    retval = xc_dom_pfn_to_ptr(dom, seg->pfn, pages);
+    *pages_out = retval ? pages : 0;
+    return retval;
+static inline void *xc_dom_seg_to_ptr(struct xc_dom_image *dom,
+                                      struct xc_dom_seg *seg)
+    xen_pfn_t dummy;
-    return xc_dom_pfn_to_ptr(dom, seg->pfn, pages);
+    return xc_dom_seg_to_ptr_pages(dom, seg, &dummy);
 static inline void *xc_dom_vaddr_to_ptr(struct xc_dom_image *dom,
generated by git-patchbot for /home/xen/git/xen.git#master

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