Re: [Qemu-devel] [PATCH RFC 2/4] check if we have space left for hotplugged memory

[Hu Tao]

On Sun, Jun 15, 2014 at 11:53:52AM +0300, Michael S. Tsirkin wrote:
> On Sat, Jun 14, 2014 at 12:48:57PM +0800, Hu Tao wrote:
> > If pc-dimm is specified on qemu command line, but only with
> > -m size (aka not -m size,maxmem,slots) then qemu will core dump.
> > 
> > This patch fixes the problem.
> > 
> > Signed-off-by: Hu Tao <address@hidden>
> > ---
> >  hw/mem/pc-dimm.c | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> > 
> > diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c
> > index 8c26568..6e8bf43 100644
> > --- a/hw/mem/pc-dimm.c
> > +++ b/hw/mem/pc-dimm.c
> > @@ -107,7 +107,12 @@ uint64_t pc_dimm_get_free_addr(uint64_t 
> > address_space_start,
> >      uint64_t new_addr, ret = 0;
> >      uint64_t address_space_end = address_space_start + address_space_size;
> >  
> > -    assert(address_space_end > address_space_size);
> > +    if (address_space_size == 0) {
> > +        error_setg(errp, "can't add memory beyond 0x%" PRIx64,
> > +                   address_space_end);
> 
> That's quite an unfriendly error message, isn't it?
> Why not explain what the problem is to the user?

Thanks! patch updated.

> 
> > +        goto out;
> > +    }
> > +
> 
> I would move the assert to this point. It protects against
> integer overflow.
> 
> >      object_child_foreach(qdev_get_machine(), pc_dimm_built_list, &list);
> >  
> >      if (hint) {
> 
> 
> > -- 
> > 1.9.3