From: Kiryl Shutsemau <kas@kernel.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Ard Biesheuvel <ardb@kernel.org>,
Thomas Gleixner <tglx@kernel.org>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
x86@kernel.org, linux-efi@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Moritz Sanft <ms@edgeless.systems>
Subject: Re: [PATCH 1/2] efi: Fix reservation of unaccepted memory table
Date: Fri, 13 Feb 2026 16:14:38 +0000 [thread overview]
Message-ID: <aY9Mf8oZODGiDoXp@thinkstation> (raw)
In-Reply-To: <b3b073e4-d51e-4fd7-ad7c-7465dab412b6@intel.com>
On Fri, Feb 13, 2026 at 08:01:55AM -0800, Dave Hansen wrote:
> On 2/13/26 07:48, Kiryl Shutsemau (Meta) wrote:
> > static __init void reserve_unaccepted(struct efi_unaccepted_memory *unaccepted)
> > {
> > - phys_addr_t start, size;
> > + phys_addr_t start, end;
> >
> > start = PAGE_ALIGN_DOWN(efi.unaccepted);
>
> Why are we even aligning the start? Isn't *that* the bug?
How so? It is up to EFI how the table is allocated. We need to be sure
that this memory is mapped and not overwritten.
> The memblock code seems to be able to handle arbitrary alignment just fine.
Memblock will track it, but, as the comment says, anything smaller than
page size will not be mapped, but we need the table to be accessible by
kernel.
--
Kiryl Shutsemau / Kirill A. Shutemov
next prev parent reply other threads:[~2026-02-13 16:14 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-13 15:48 [PATCH 0/2] efi: Fix alignenment issues in unaccepted memory code Kiryl Shutsemau (Meta)
2026-02-13 15:48 ` [PATCH 1/2] efi: Fix reservation of unaccepted memory table Kiryl Shutsemau (Meta)
2026-02-13 16:01 ` Dave Hansen
2026-02-13 16:14 ` Kiryl Shutsemau [this message]
2026-02-13 16:46 ` Dave Hansen
2026-02-13 17:20 ` Kiryl Shutsemau
2026-02-14 15:51 ` Mike Rapoport
2026-02-16 14:22 ` Kiryl Shutsemau
2026-02-16 14:51 ` Mike Rapoport
2026-02-16 15:53 ` Dave Hansen
2026-02-16 16:19 ` Mike Rapoport
2026-02-13 15:48 ` [PATCH 2/2] efi: Align unaccepted memory range to page boundary Kiryl Shutsemau (Meta)
2026-02-16 14:51 ` Tom Lendacky
2026-02-16 15:33 ` Kiryl Shutsemau
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