Re: [Qemu-devel] [PATCH] numa: set the memory backend "is_mapped" field

[Eduardo Habkost]

On Tue, Jul 19, 2016 at 12:07:53PM +0200, Igor Mammedov wrote:
> On Tue, 19 Jul 2016 10:28:35 +0200
> Greg Kurz <address@hidden> wrote:
> 
> > Commit 2aece63 "hostmem: detect host backend memory is being used properly"
> > added a way to know if a memory backend is busy or available for use. It
> > caused a slight regression if we pass the same backend to a NUMA node and
> > to a pc-dimm device:
> > 
> > -m 1G,slots=2,maxmem=2G \
> > -object memory-backend-ram,size=1G,id=mem-mem1 \
> > -device pc-dimm,id=dimm-mem1,memdev=mem-mem1 \
> > -numa node,nodeid=0,memdev=mem-mem1
> > 
> > Before commit 2aece63, this would cause QEMU to print an error message and
> > to exit gracefully:
> > 
> > qemu-system-ppc64: -device pc-dimm,id=dimm-mem1,memdev=mem-mem1:
> >     can't use already busy memdev: mem-mem1
> > 
> > Since commit 2aece63, QEMU hits an assertion in the memory code:
> > 
> > qemu-system-ppc64: memory.c:1934: memory_region_add_subregion_common:
> >     Assertion `!subregion->container' failed.
> > Aborted
> > 
> > This happens because pc-dimm devices don't use memory_region_is_mapped()
> > anymore and cannot guess the backend is already used by a NUMA node.
> > 
> > Let's revert to the previous behavior by turning the NUMA code to also
> > call host_memory_backend_set_mapped() when it uses a backend.
> > 
> > Fixes: 2aece63c8a9d2c3a8ff41d2febc4cdeff2633331
> > Signed-off-by: Greg Kurz <address@hidden>
> Reviewed-by: Igor Mammedov <address@hidden>

I have just noticed that this fell through the cracks, sorry.
Applied to numa-next. Thanks!

-- 
Eduardo