From: Ard Biesheuvel <ardb+git@google.com>
To: linux-kernel@vger.kernel.org
Cc: linux-efi@vger.kernel.org, x86@kernel.org,
Ard Biesheuvel <ardb@kernel.org>,
"Mike Rapoport (Microsoft)" <rppt@kernel.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: [PATCH v2 03/19] x86/efi: Unmap kernel-reserved boot regions from EFI page tables
Date: Thu, 19 Mar 2026 10:05:33 +0100 [thread overview]
Message-ID: <20260319090529.1091660-24-ardb+git@google.com> (raw)
In-Reply-To: <20260319090529.1091660-21-ardb+git@google.com>
From: Ard Biesheuvel <ardb@kernel.org>
Currently, the logic that unmaps boot services code and data regions
that were mapped temporarily to work around firmware bugs disregards
regions that have been marked as EFI_MEMORY_RUNTIME. However, such
regions only have significance to the OS, and there is no reason to
retain the mapping in the EFI page tables, given that the runtime
firmware must never touch those regions.
So pull the unmap forward.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/x86/platform/efi/quirks.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 35caa5746115..30b8012eafaa 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -442,12 +442,6 @@ void __init efi_unmap_boot_services(void)
continue;
}
- /* Do not free, someone else owns it: */
- if (md->attribute & EFI_MEMORY_RUNTIME) {
- num_entries++;
- continue;
- }
-
/*
* Before calling set_virtual_address_map(), EFI boot services
* code/data regions were mapped as a quirk for buggy firmware.
@@ -455,6 +449,12 @@ void __init efi_unmap_boot_services(void)
*/
efi_unmap_pages(md);
+ /* Do not free, someone else owns it: */
+ if (md->attribute & EFI_MEMORY_RUNTIME) {
+ num_entries++;
+ continue;
+ }
+
/*
* Nasty quirk: if all sub-1MB memory is used for boot
* services, we can get here without having allocated the
--
2.53.0.851.ga537e3e6e9-goog
next prev parent reply other threads:[~2026-03-19 9:06 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-19 9:05 [PATCH v2 00/19] efi/x86: Avoid the need to mangle the EFI memory map Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 01/19] memblock: Permit existing reserved regions to be marked RSRV_KERN Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 02/19] efi: Tag memblock reservations of boot services regions as RSRV_KERN Ard Biesheuvel
2026-03-19 9:05 ` Ard Biesheuvel [this message]
2026-03-19 9:05 ` [PATCH v2 04/19] x86/efi: Drop EFI_MEMORY_RUNTIME check from __ioremap_check_other() Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 05/19] x86/efi: Omit RSRV_KERN memblock reservations when freeing boot regions Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 06/19] x86/efi: Defer sub-1M check from unmap to free stage Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 07/19] x86/efi: Simplify real mode trampoline allocation quirk Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 08/19] x86/efi: Omit redundant kernel image overlap check Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 09/19] x86/efi: Drop redundant EFI_PARAVIRT check Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 10/19] x86/efi: Do not rely on EFI_MEMORY_RUNTIME bit and avoid entry splitting Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 11/19] efi: Use nr_map not map_end to find the last valid memory map entry Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 12/19] x86/efi: Only merge EFI memory map entries on 32-bit systems Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 13/19] x86/efi: Clean the memory map using iterator and filter API Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 14/19] x86/efi: Update the runtime map in place Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 15/19] x86/efi: Use iterator API when mapping EFI regions for runtime Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 16/19] x86/efi: Reuse memory map instead of reallocating it Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 17/19] x86/efi: Defer compaction of the EFI memory map Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 18/19] x86/efi: Do not abuse RUNTIME bit to mark boot regions as reserved Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 19/19] x86/efi: Free unused tail of the EFI memory map Ard Biesheuvel
2026-03-24 9:50 ` [PATCH v2 00/19] efi/x86: Avoid the need to mangle " Ard Biesheuvel
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260319090529.1091660-24-ardb+git@google.com \
--to=ardb+git@google.com \
--cc=ardb@kernel.org \
--cc=benh@kernel.crashing.org \
--cc=linux-efi@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=rppt@kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox