Re: [PATCH] hw/cxl/cxl-host: Fix guest crash when getting cxl-fmw property

[Jonathan Cameron via <qemu-devel@nongnu.org>]

On Fri, 5 Jul 2024 02:39:51 +0000
"Zhijian Li (Fujitsu)" <lizhijian@fujitsu.com> wrote:

> On 04/07/2024 17:34, Zhao Liu wrote:
> > From: Zhao Liu <zhao1.liu@intel.com>
> > 
> > Guest crashes (Segmentation fault) when getting cxl-fmw property via
> > qmp:
> >   
> 
> IMO, it's fair to say "Guest crashes" which generally means the guest kernel panic etc.
> I'd prefer the subject like:
> hw/cxl/cxl-host: Fix segmentation fault when getting cxl-fmw property
Agreed. I've picked this up and edited the description.

I've just hit send on a v2 of the misc minor fixes series with this
replacing the patch that dropped cfmws_list

Thanks,

Jonathan


> 
> 
> Otherwise,
> 
> Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
> 
> 
> > (QEMU) qom-get path=machine property=cxl-fmw
> > 
> > This issue is caused by accessing wrong callback (opaque) type in
> > machine_get_cfmw().
> > 
> > cxl_machine_init() sets the callback as `CXLState *` type but
> > machine_get_cfmw() treats the callback as
> > `CXLFixedMemoryWindowOptionsList **`.
> > 
> > Fix this error by casting opaque to `CXLState *` type in
> > machine_get_cfmw().
> > 
> > Fixes: 03b39fcf64bc ("hw/cxl: Make the CXL fixed memory window setup a machine parameter.")
> > Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
> > ---
> >   hw/cxl/cxl-host.c | 3 ++-
> >   1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/hw/cxl/cxl-host.c b/hw/cxl/cxl-host.c
> > index c5f5fcfd64d0..e9f2543c43c6 100644
> > --- a/hw/cxl/cxl-host.c
> > +++ b/hw/cxl/cxl-host.c
> > @@ -315,7 +315,8 @@ static void machine_set_cxl(Object *obj, Visitor *v, const char *name,
> >   static void machine_get_cfmw(Object *obj, Visitor *v, const char *name,
> >                                void *opaque, Error **errp)
> >   {
> > -    CXLFixedMemoryWindowOptionsList **list = opaque;
> > +    CXLState *state = opaque;
> > +    CXLFixedMemoryWindowOptionsList **list = &state->cfmw_list;
> >   
> >       visit_type_CXLFixedMemoryWindowOptionsList(v, name, list, errp);
> >