[Xen-changelog] [xen master] xen: arm: process XENMEM_add_to_physmap_range forwards not backwards.

[patchbot@xxxxxxx]

commit cd50b8cae268fc66969e2f3858e79c244a0eea0b
Author:     Ian Campbell <ian.campbell@xxxxxxxxxx>
AuthorDate: Wed Dec 18 13:39:14 2013 +0000
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Wed Dec 18 14:14:17 2013 +0000

    xen: arm: process XENMEM_add_to_physmap_range forwards not backwards.
    
    Jan points out that processing the list backwards is rather counter 
intuitive
    and that the effect of the hypercall can differ between forwards and 
backwards
    processing (e.g. in the presence of duplicate idx or gpfn, which would be
    unusual but as Jan says, users are a creative bunch)
    
    Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    Cc: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
---
 xen/arch/arm/mm.c |   13 ++++++-------
 1 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 654281a..726adc7 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -1061,21 +1061,18 @@ static int xenmem_add_to_physmap_range(struct domain *d,
 {
     int rc;
 
-    /* Process entries in reverse order to allow continuations */
     while ( xatpr->size > 0 )
     {
         xen_ulong_t idx;
         xen_pfn_t gpfn;
 
-        if ( unlikely(copy_from_guest_offset(&idx, xatpr->idxs,
-                                             xatpr->size-1, 1)) )
+        if ( unlikely(copy_from_guest_offset(&idx, xatpr->idxs, 0, 1)) )
         {
             rc = -EFAULT;
             goto out;
         }
 
-        if ( unlikely(copy_from_guest_offset(&gpfn, xatpr->gpfns,
-                                             xatpr->size-1, 1)) )
+        if ( unlikely(copy_from_guest_offset(&gpfn, xatpr->gpfns, 0, 1)) )
         {
             rc = -EFAULT;
             goto out;
@@ -1085,8 +1082,7 @@ static int xenmem_add_to_physmap_range(struct domain *d,
                                        xatpr->foreign_domid,
                                        idx, gpfn);
 
-        if ( unlikely(copy_to_guest_offset(xatpr->errs,
-                                           xatpr->size-1, &rc, 1)) )
+        if ( unlikely(copy_to_guest_offset(xatpr->errs, 0, &rc, 1)) )
         {
             rc = -EFAULT;
             goto out;
@@ -1095,6 +1091,9 @@ static int xenmem_add_to_physmap_range(struct domain *d,
         if ( rc < 0 )
             goto out;
 
+        guest_handle_add_offset(xatpr->idxs, 1);
+        guest_handle_add_offset(xatpr->gpfns, 1);
+        guest_handle_add_offset(xatpr->errs, 1);
         xatpr->size--;
 
         /* Check for continuation if it's not the last interation */
--
generated by git-patchbot for /home/xen/git/xen.git#master

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