linux-kernel - Re: [PATCH] efi: avoid error message when booting under Xen

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Message-ID: <CAMj1kXGE52Y6QQhGLU6r_9x6TVftZqfS7zyLCiDusZhV4tbhjg@mail.gmail.com>
Date:   Fri, 10 Jul 2020 16:27:23 +0300
From:   Ard Biesheuvel <ardb@...nel.org>
To:     Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Cc:     Jürgen Groß <jgross@...e.com>,
        xen-devel@...ts.xenproject.org, linux-fbdev@...r.kernel.org,
        dri-devel@...ts.freedesktop.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Peter Jones <pjones@...hat.com>,
        linux-efi <linux-efi@...r.kernel.org>
Subject: Re: [PATCH] efi: avoid error message when booting under Xen

On Fri, 10 Jul 2020 at 13:17, Bartlomiej Zolnierkiewicz
<b.zolnierkie@...sung.com> wrote:
>
>
> [ added EFI Maintainer & ML to Cc: ]
>
> Hi,
>
> On 7/9/20 11:17 AM, Jürgen Groß wrote:
> > On 28.06.20 10:50, Jürgen Groß wrote:
> >> Ping?
> >>
> >> On 10.06.20 16:10, Juergen Gross wrote:
> >>> efifb_probe() will issue an error message in case the kernel is booted
> >>> as Xen dom0 from UEFI as EFI_MEMMAP won't be set in this case. Avoid
> >>> that message by calling efi_mem_desc_lookup() only if EFI_PARAVIRT
> >>> isn't set.
> >>>

Why not test for EFI_MEMMAP instead of EFI_BOOT?


> >>> Fixes: 38ac0287b7f4 ("fbdev/efifb: Honour UEFI memory map attributes when mapping the FB")
> >>> Signed-off-by: Juergen Gross <jgross@...e.com>
> >>> ---
> >>>   drivers/video/fbdev/efifb.c | 2 +-
> >>>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
> >>> index 65491ae74808..f5eccd1373e9 100644
> >>> --- a/drivers/video/fbdev/efifb.c
> >>> +++ b/drivers/video/fbdev/efifb.c
> >>> @@ -453,7 +453,7 @@ static int efifb_probe(struct platform_device *dev)
> >>>       info->apertures->ranges[0].base = efifb_fix.smem_start;
> >>>       info->apertures->ranges[0].size = size_remap;
> >>> -    if (efi_enabled(EFI_BOOT) &&
> >>> +    if (efi_enabled(EFI_BOOT) && !efi_enabled(EFI_PARAVIRT) &&
> >>>           !efi_mem_desc_lookup(efifb_fix.smem_start, &md)) {
> >>>           if ((efifb_fix.smem_start + efifb_fix.smem_len) >
> >>>               (md.phys_addr + (md.num_pages << EFI_PAGE_SHIFT))) {
> >>>
> >>
> >
> > In case I see no reaction from the maintainer for another week I'll take
> > this patch through the Xen tree.
>
> From fbdev POV this change looks fine to me and I'm OK with merging it
> through Xen or EFI tree:
>
> Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
>
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics