Re: [PATCH 1/4] hvm: NUMA guest: extend memops hypercall

[Andre Przywara <andre.przywara@amd.com>]

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Keir Fraser wrote:
> On 4/7/08 08:57, "Andre Przywara" <andre.przywara@amd.com> wrote:
> 
>> This patch extends the memops hypercall in a compatible way to transport
>> a desired NUMA node number. The address_bits field will be limited to 8
>> bits and is now embedded in the mem_flags member, which additionally
>> contains the node number (limited to 8 bit). Passing a node number of
>> '0' (currently the default) will revert to automatic node selection
>> (based on currently scheduled node).
> 
> Should unprivileged domUs be allowed to specify the NUMA node they allocate
> from, regardless of whether they even run there? Seems like a breakage of
> guest isolation to me.
Good catch (I code in HVM land most of the time), I hope this small 
(attached) patch fixes this.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>

Regards,
Andre.

-- 
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 277-84917
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diff -r aa69281c1ecf xen/common/memory.c
--- a/xen/common/memory.c	Thu Jul 03 13:20:35 2008 +0200
+++ b/xen/common/memory.c	Fri Jul 04 13:13:12 2008 +0200
@@ -528,7 +528,8 @@
             args.memflags = MEMF_bits(XENMEM_addr_bits(reservation.mem_flags));
         }
 
-        args.memflags |= MEMF_node(XENMEM_get_node(reservation.mem_flags));
+        if (IS_PRIV(current->domain))
+            args.memflags |= MEMF_node(XENMEM_get_node(reservation.mem_flags));
 
         if ( likely(reservation.domid == DOMID_SELF) )
         {

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