Re: [Qemu-devel] [PATCH qemu v14 12/18] vfio: Check that IOMMU MR translates to system address space

[Alexey Kardashevskiy]

On 03/23/2016 02:47 AM, Alex Williamson wrote:
> On Tue, 22 Mar 2016 14:05:15 +1100
> David Gibson <address@hidden> wrote:
>
> > On Mon, Mar 21, 2016 at 06:47:00PM +1100, Alexey Kardashevskiy wrote:
> > > At the moment IOMMU MR only translate to the system memory.
> > > However if some new code changes this, we will need clear indication why
> > > it is not working so here is the check.
> > >
> > > Signed-off-by: Alexey Kardashevskiy <address@hidden>
> >
> > Reviewed-by: David Gibson <address@hidden>
> >
> > Alex, any chance we could merge this quickly, since it is a reasonable
> > sanity check even without the rest of the changes.
>
> It all sounds very theoretical to inspire some rush to merge it
> quickly, is there any chance we could actually hit this currently?


The chances are as big as chances that some platform starts supporting VFIO 
soon, for these new folks such a check would be a good piece of 
documentation or at least a warning trigger to ask a question in the lists.



> > > ---
> > > Changes:
> > > v14:
> > > * new to the series
> > > ---
> > >   hw/vfio/common.c | 6 ++++++
> > >   1 file changed, 6 insertions(+)
> > >
> > > diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> > > index 55723c9..9587c25 100644
> > > --- a/hw/vfio/common.c
> > > +++ b/hw/vfio/common.c
> > > @@ -266,6 +266,12 @@ static void vfio_iommu_map_notify(Notifier *n, void *data)
> > >
> > >       trace_vfio_iommu_map_notify(iova, iova + iotlb->addr_mask);
> > >
> > > +    if (iotlb->target_as != &address_space_memory) {
> > > +        error_report("Wrong target AS \"%s\", only system memory is allowed",
> > > +                     iotlb->target_as->name?iotlb->target_as->name:"noname");
>
> Spaces please.
>
> > > +        return;
> > > +    }
> > > +
> > >       /*
> > >        * The IOMMU TLB entry we have just covers translation through
> > >        * this IOMMU to its immediate target.  We need to translate


--
Alexey