linux-kernel - Re: [PATCH] efi: bump up EFI_MMAP_NR_SLACK

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAMj1kXHmB9RAwfCDZN+CDhXD4D6Z1sE6vg5HN3SUEZ+uLnEnWg@mail.gmail.com>
Date: Thu, 19 Dec 2024 11:26:21 +0100
From: Ard Biesheuvel <ardb@...nel.org>
To: Hamza Mahfooz <hamzamahfooz@...ux.microsoft.com>
Cc: linux-efi@...r.kernel.org, stable@...nel.org, 
	Allen Pais <apais@...ux.microsoft.com>, Tyler Hicks <code@...icks.com>, 
	Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>, 
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>, Andrew Morton <akpm@...ux-foundation.org>, 
	Jonathan Marek <jonathan@...ek.ca>, open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] efi: bump up EFI_MMAP_NR_SLACK_SLOTS to 32

On Tue, 10 Dec 2024 at 10:59, Ard Biesheuvel <ardb@...nel.org> wrote:
>
> On Mon, 9 Dec 2024 at 19:20, Hamza Mahfooz
> <hamzamahfooz@...ux.microsoft.com> wrote:
> >
> > Recent platforms require more slack slots than the current value of
> > EFI_MMAP_NR_SLACK_SLOTS, otherwise they fail to boot. The current
> > workaround is to append `efi=disable_early_pci_dma` to the kernel's
> > cmdline. So, bump up EFI_MMAP_NR_SLACK_SLOTS to 32 to allow those
> > platforms to boot with the aforementioned workaround.
> >
> > Cc: stable@...nel.org
> > Cc: Ard Biesheuvel <ardb@...nel.org>
> > Cc: Allen Pais <apais@...ux.microsoft.com>
> > Cc: Tyler Hicks <code@...icks.com>
> > Signed-off-by: Hamza Mahfooz <hamzamahfooz@...ux.microsoft.com>
> > ---
> >  drivers/firmware/efi/libstub/efistub.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
> > index 76e44c185f29..e95ce6ae5c26 100644
> > --- a/drivers/firmware/efi/libstub/efistub.h
> > +++ b/drivers/firmware/efi/libstub/efistub.h
> > @@ -171,7 +171,7 @@ void efi_set_u64_split(u64 data, u32 *lo, u32 *hi)
> >   * the EFI memory map. Other related structures, e.g. x86 e820ext, need
> >   * to factor in this headroom requirement as well.
> >   */
> > -#define EFI_MMAP_NR_SLACK_SLOTS        8
> > +#define EFI_MMAP_NR_SLACK_SLOTS        32
> >
> >  typedef struct efi_generic_dev_path efi_device_path_protocol_t;
> >
>
> Acked-by: Ard Biesheuvel <ardb@...nel.org>

I've queued this up for v6.14 now - once we are confident it does not
cause any regressions, we can backport it to stable branches too.