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>,
Tom Lendacky <thomas.lendacky@amd.com>
Subject: [PATCH v2 04/19] x86/efi: Drop EFI_MEMORY_RUNTIME check from __ioremap_check_other()
Date: Thu, 19 Mar 2026 10:05:34 +0100 [thread overview]
Message-ID: <20260319090529.1091660-25-ardb+git@google.com> (raw)
In-Reply-To: <20260319090529.1091660-21-ardb+git@google.com>
From: Ard Biesheuvel <ardb@kernel.org>
__ioremap_check_other() is called when memremap() is used on memory that
turns out to be reserved. This may be the case for ESRT or MOK tables
that are reserved via efi_mem_reserve(), in which case they will be
covered by EfiBootServicesData entries in the EFI memory map.
Such entries are created with the EFI_MEMORY_RUNTIME attribute set, to
distinguish them from EfiBootServicesData entries that were reserved
only temporarily, in order to work around firmware bugs.
However, given that
a) __ioremap_check_other() is only called for memory that could not be
mapped using try_ram_remap(),
b) on x86, the EFI memory map only retains EfiBootServicesData entries that
cover a permanent reservation,
the EFI_MEMORY_RUNTIME check is redundant, and can be dropped.
This removes the need to set this attribute in the first place, which is
desirable as it results in considerable complexity in managing the EFI
memory map on x86. This is implemented in subsequent patches.
While at it, use switch() rather than if() to avoid multiple calls to
efi_mem_type(), which is backed by a hypervisor call in some cases.
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/x86/mm/ioremap.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 12c8180ca1ba..2d0e1cfb9054 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -124,9 +124,9 @@ static void __ioremap_check_other(resource_size_t addr, struct ioremap_desc *des
if (!IS_ENABLED(CONFIG_EFI))
return;
- if (efi_mem_type(addr) == EFI_RUNTIME_SERVICES_DATA ||
- (efi_mem_type(addr) == EFI_BOOT_SERVICES_DATA &&
- efi_mem_attributes(addr) & EFI_MEMORY_RUNTIME))
+ switch (efi_mem_type(addr))
+ case EFI_RUNTIME_SERVICES_DATA:
+ case EFI_BOOT_SERVICES_DATA:
desc->flags |= IORES_MAP_ENCRYPTED;
}
--
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 ` [PATCH v2 03/19] x86/efi: Unmap kernel-reserved boot regions from EFI page tables Ard Biesheuvel
2026-03-19 9:05 ` Ard Biesheuvel [this message]
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=20260319090529.1091660-25-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=thomas.lendacky@amd.com \
--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