[PULL,13/18] spapr: add pre_plug function for memory

From: Laurent Vivier <lvivier@redhat.com>

This allows to manage errors before the memory
has started to be hotplugged. We already have
the function for the CPU cores.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
[dwg: Fixed a couple of style nits]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 hw/ppc/spapr.c | 41 ++++++++++++++++++++++++++---------------
 1 file changed, 26 insertions(+), 15 deletions(-)

On 25 May 2017 at 04:51, David Gibson <david@gibson.dropbear.id.au> wrote:
> From: Laurent Vivier <lvivier@redhat.com>
>
> This allows to manage errors before the memory
> has started to be hotplugged. We already have
> the function for the CPU cores.

> +static void spapr_memory_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
> +                                  Error **errp)
> +{
> +    PCDIMMDevice *dimm = PC_DIMM(dev);
> +    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
> +    MemoryRegion *mr = ddc->get_memory_region(dimm);
> +    uint64_t size = memory_region_size(mr);
> +    char *mem_dev;
> +
> +    if (size % SPAPR_MEMORY_BLOCK_SIZE) {
> +        error_setg(errp, "Hotplugged memory size must be a multiple of "
> +                      "%lld MB", SPAPR_MEMORY_BLOCK_SIZE / M_BYTE);
> +        return;
> +    }
> +
> +    mem_dev = object_property_get_str(OBJECT(dimm), PC_DIMM_MEMDEV_PROP, NULL);
> +    if (mem_dev && !kvmppc_is_mem_backend_page_size_ok(mem_dev)) {
> +        error_setg(errp, "Memory backend has bad page size. "
> +                   "Use 'memory-backend-file' with correct mem-path.");
> +        return;
> +    }
> +}

Coverity points out that this leaks memory -- object_property_get_str()
returns a copy of a string which the caller is supposed to free, but
this code doesn't free it. (CID 1375942.)

thanks
-- PMM

On Tue, 6 Jun 2017 16:00:32 +0100
Peter Maydell <peter.maydell@linaro.org> wrote:

> On 25 May 2017 at 04:51, David Gibson <david@gibson.dropbear.id.au> wrote:
> > From: Laurent Vivier <lvivier@redhat.com>
> >
> > This allows to manage errors before the memory
> > has started to be hotplugged. We already have
> > the function for the CPU cores.  
> 
> > +static void spapr_memory_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
> > +                                  Error **errp)
> > +{
> > +    PCDIMMDevice *dimm = PC_DIMM(dev);
> > +    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
> > +    MemoryRegion *mr = ddc->get_memory_region(dimm);
> > +    uint64_t size = memory_region_size(mr);
> > +    char *mem_dev;
> > +
> > +    if (size % SPAPR_MEMORY_BLOCK_SIZE) {
> > +        error_setg(errp, "Hotplugged memory size must be a multiple of "
> > +                      "%lld MB", SPAPR_MEMORY_BLOCK_SIZE / M_BYTE);
> > +        return;
> > +    }
> > +
> > +    mem_dev = object_property_get_str(OBJECT(dimm), PC_DIMM_MEMDEV_PROP, NULL);
> > +    if (mem_dev && !kvmppc_is_mem_backend_page_size_ok(mem_dev)) {
> > +        error_setg(errp, "Memory backend has bad page size. "
> > +                   "Use 'memory-backend-file' with correct mem-path.");
> > +        return;
> > +    }
> > +}  
> 
> Coverity points out that this leaks memory -- object_property_get_str()
> returns a copy of a string which the caller is supposed to free, but
> this code doesn't free it. (CID 1375942.)
> 

Yeah, I've received the Coverity report as well. This is a regression introduced
in 2.9 by commit df58713396f8 ("hw/ppc/spapr: Check for valid page size when hot
plugging memory") actually.

The same commit also introduces a similar leak in
kvmppc_is_mem_backend_page_size_ok().

I'm about to send a series to fix both.

Cheers.

--
Greg

> thanks
> -- PMM
>