Re: [PATCH RFC v3 32/36] kmsan: add iomap support

[Alexander Potapenko <glider@google.com>]

On Tue, Dec 3, 2019 at 1:51 PM Marco Elver <elver@google.com> wrote:
>
> On Fri, 22 Nov 2019 at 12:28, <glider@google.com> wrote:
> >
> > Functions from lib/iomap.c interact with hardware, so KMSAN must ensure
> > that:
> >  - every read function returns an initialized value
> >  - every write function checks values before sending them to hardware.
> >
> > Signed-off-by: Alexander Potapenko <glider@google.com>
> > Cc: Christoph Hellwig <hch@infradead.org>
> > Cc: Darrick J. Wong <darrick.wong@oracle.com>
> > Cc: Vegard Nossum <vegard.nossum@oracle.com>
> > Cc: Dmitry Vyukov <dvyukov@google.com>
> > Cc: linux-mm@kvack.org
> > ---
> >
> > Change-Id: Iacd96265e56398d8c111637ddad3cad727e48c8d
> > ---
> >  lib/iomap.c | 40 ++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 40 insertions(+)
> >
> > diff --git a/lib/iomap.c b/lib/iomap.c
> > index e909ab71e995..3ef20b8138e2 100644
> > --- a/lib/iomap.c
> > +++ b/lib/iomap.c
> > @@ -6,6 +6,7 @@
> [...]
> >  void iowrite8_rep(void __iomem *addr, const void *src, unsigned long count)
> >  {
> > +       /* Make sure uninitialized memory isn't copied to devices. */
> > +       kmsan_check_memory(src, count);
> >         IO_COND(addr, outsb(port, src, count), mmio_outsb(addr, src, count));
> >  }
> >  void iowrite16_rep(void __iomem *addr, const void *src, unsigned long count)
> >  {
> > +       /* Make sure uninitialized memory isn't copied to devices. */
> > +       kmsan_check_memory(src, count);
>
> Should this be 'count * 2' ?
Good catch, thanks!
Will fix in v4.
>
> >         IO_COND(addr, outsw(port, src, count), mmio_outsw(addr, src, count));
> >  }
> >  void iowrite32_rep(void __iomem *addr, const void *src, unsigned long count)
> >  {
> > +       /* Make sure uninitialized memory isn't copied to devices. */
> > +       kmsan_check_memory(src, count);
>
> Should this be 'count * 4' ?
Ditto
> Thanks,
> -- Marco



-- 
Alexander Potapenko
Software Engineer

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