From: Borislav Petkov <bp@alien8.de>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>,
linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Michael Roth <michael.roth@amd.com>
Subject: Re: [PATCH v3 00/17] x86: head_64.S spring cleaning
Date: Wed, 23 Nov 2022 12:09:08 +0100 [thread overview]
Message-ID: <Y33/VIsB5HGREY4i@zn.tnic> (raw)
In-Reply-To: <CAMj1kXGnGz+V3tmonitY+3TiWuWJFWj-mQLUbRo+xp8UwZ_SpQ@mail.gmail.com>
On Wed, Nov 23, 2022 at 11:52:32AM +0100, Ard Biesheuvel wrote:
> The patch moves it from .data to .bss inadvertently, and I am not
> convinced Tom's analysis is entirely accurate: we may simply have
> garbage in image_offset if we access it before .bss gets cleared.
That should not be too hard to find out: add an endless loop in asm in
the guest right after the first image_offset access:
1:
jmp 1b
and then dump its value.
Or Tom might have an even better solution.
But looking at the code, BSS clearing happens later, at .Lrelocated and
the EFI stub comes before it. AFAICT.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2022-11-23 11:11 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-22 16:10 [PATCH v3 00/17] x86: head_64.S spring cleaning Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 01/17] x86/compressed: efi-mixed: rename efi_thunk_64.S to efi-mixed.S Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed: Rename " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 02/17] x86/compressed: efi-mixed: move 32-bit entrypoint code into .text section Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed: Move " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 03/17] x86/compressed: efi-mixed: move bootargs parsing out of 32-bit startup code Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed: Move " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 04/17] x86/compressed: efi-mixed: move efi32_pe_entry into .text section Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed: Move " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 05/17] x86/compressed: efi-mixed: move efi32_entry out of head_64.S Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed: Move " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 06/17] x86/compressed: efi-mixed: move efi32_pe_entry() " Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed: Move " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 07/17] x86/compressed: efi: merge multiple definitions of image_offset into one Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed, efi: Merge " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 08/17] x86/compressed: efi-mixed: simplify IDT/GDT preserve/restore Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed: Simplify IDT/GDT preserve/restore in the EFI thunk tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 09/17] x86/compressed: avoid touching ECX in startup32_set_idt_entry() Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed: Avoid " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 10/17] x86/compressed: pull global variable ref up into startup32_load_idt() Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed: Pull global variable reference " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 11/17] x86/compressed: move startup32_load_idt() into .text section Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed: Move " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 12/17] x86/compressed: move startup32_load_idt() out of head_64.S Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed: Move " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 13/17] x86/compressed: move startup32_check_sev_cbit() into .text Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed: Move " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 14/17] x86/compressed: move startup32_check_sev_cbit() out of head_64.S Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed: Move " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 15/17] x86/compressed: adhere to calling convention in get_sev_encryption_bit() Ard Biesheuvel
2022-11-24 8:12 ` [tip: x86/boot] x86/boot/compressed: Adhere " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 16/17] x86/compressed: only build mem_encrypt.S if AMD_MEM_ENCRYPT=y Ard Biesheuvel
2022-11-24 8:11 ` [tip: x86/boot] x86/boot/compressed: Only " tip-bot2 for Ard Biesheuvel
2022-11-22 16:10 ` [PATCH v3 17/17] efi: x86: Make the deprecated EFI handover protocol optional Ard Biesheuvel
2022-11-22 18:56 ` Randy Dunlap
2022-11-24 8:11 ` [tip: x86/boot] x86/efi: " tip-bot2 for Ard Biesheuvel
2022-11-22 20:48 ` [PATCH v3 00/17] x86: head_64.S spring cleaning Tom Lendacky
2022-11-22 21:37 ` Ard Biesheuvel
2022-11-22 21:42 ` Ard Biesheuvel
2022-11-22 21:50 ` Tom Lendacky
2022-11-22 21:51 ` Ard Biesheuvel
2022-11-22 21:49 ` Tom Lendacky
2022-11-22 22:20 ` Borislav Petkov
2022-11-23 10:49 ` Borislav Petkov
2022-11-23 10:52 ` Ard Biesheuvel
2022-11-23 11:09 ` Borislav Petkov [this message]
2022-11-23 11:22 ` Ard Biesheuvel
2022-11-23 14:16 ` Tom Lendacky
2022-11-23 14:33 ` Ard Biesheuvel
2022-11-23 14:13 ` Tom Lendacky
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