Re: [PATCH v2 2/2] fbdev/efifb: honour UEFI memory map attributes when mapping the fb

[Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>]

On Monday, June 25, 2018 11:58:11 AM Ard Biesheuvel wrote:
> ,On 22 June 2018 at 09:52, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> > If the framebuffer address provided by the Graphics Output Protocol
> > (GOP) is covered by the UEFI memory map, it will tell us which memory
> > attributes are permitted when mapping this region. In some cases,
> > (KVM guest on ARM), violating this will result in loss of coherency,
> > which means that updates sent to the framebuffer by the guest will
> > not be observeable by the host, and the emulated display simply does
> > not work.
> >
> > So if the memory map contains such a description, take the attributes
> > field into account, and add support for creating WT or WB mappings of
> > the framebuffer region.
> >
> > Cc: linux-fbdev@vger.kernel.org
> > Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> > Cc: Peter Jones <pjones@redhat.com>
> > Tested-by: Laszlo Ersek <lersek@redhat.com>
> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> 
> Bartlomiej, do you have any comments on this patch? If not, I would
> like to queue it in the efi tree.

> > @@ -164,6 +168,8 @@ static int efifb_probe(struct platform_device *dev)
> >         unsigned int size_remap;
> >         unsigned int size_total;
> >         char *option = NULL;
> > +       efi_memory_desc_t md;
> > +
> >

minor nit: redundant newline

the rest looks fine to me

Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics