Commit Graph

1332 Commits

Author SHA1 Message Date
Ard Biesheuvel
8ed12ab131 x86/boot/sev: Support memory acceptance in the EFI stub under SVSM
Commit:

  d54d610243 ("x86/boot/sev: Avoid shared GHCB page for early memory acceptance")

provided a fix for SEV-SNP memory acceptance from the EFI stub when
running at VMPL #0. However, that fix was insufficient for SVSM SEV-SNP
guests running at VMPL >0, as those rely on a SVSM calling area, which
is a shared buffer whose address is programmed into a SEV-SNP MSR, and
the SEV init code that sets up this calling area executes much later
during the boot.

Given that booting via the EFI stub at VMPL >0 implies that the firmware
has configured this calling area already, reuse it for performing memory
acceptance in the EFI stub.

Fixes: fcd042e864 ("x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0")
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Co-developed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>
Cc: Dionna Amalie Glaze <dionnaglaze@google.com>
Cc: Kevin Loughlin <kevinloughlin@google.com>
Cc: linux-efi@vger.kernel.org
Link: https://lore.kernel.org/r/20250428174322.2780170-2-ardb+git@google.com
2025-05-04 08:20:27 +02:00
Ard Biesheuvel
032ce1ea94 x86/boot: Work around broken busybox 'truncate' tool
The GNU coreutils version of truncate, which is the original, accepts a
% prefix for the -s size argument which means the file in question
should be padded to a multiple of the given size. This is currently used
to pad the setup block of bzImage to a multiple of 4k before appending
the decompressor.

busybox reimplements truncate but does not support this idiom, and
therefore fails the build since commit

  9c54baab44 ("x86/boot: Drop CRC-32 checksum and the build tool that generates it")

Since very little build code within the kernel depends on the 'truncate'
utility, work around this incompatibility by avoiding truncate altogether,
and relying on dd to perform the padding.

Fixes: 9c54baab44 ("x86/boot: Drop CRC-32 checksum and the build tool that generates it")
Reported-by: <phasta@kernel.org>
Tested-by: Philipp Stanner <phasta@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250424101917.1552527-2-ardb+git@google.com
2025-04-24 18:23:27 +02:00
Ard Biesheuvel
d54d610243 x86/boot/sev: Avoid shared GHCB page for early memory acceptance
Communicating with the hypervisor using the shared GHCB page requires
clearing the C bit in the mapping of that page. When executing in the
context of the EFI boot services, the page tables are owned by the
firmware, and this manipulation is not possible.

So switch to a different API for accepting memory in SEV-SNP guests, one
which is actually supported at the point during boot where the EFI stub
may need to accept memory, but the SEV-SNP init code has not executed
yet.

For simplicity, also switch the memory acceptance carried out by the
decompressor when not booting via EFI - this only involves the
allocation for the decompressed kernel, and is generally only called
after kexec, as normal boot will jump straight into the kernel from the
EFI stub.

Fixes: 6c32117963 ("x86/sev: Add SNP-specific unaccepted memory support")
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Co-developed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>
Cc: Dionna Amalie Glaze <dionnaglaze@google.com>
Cc: Kevin Loughlin <kevinloughlin@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-efi@vger.kernel.org
Link: https://lore.kernel.org/r/20250404082921.2767593-8-ardb+git@google.com # discussion thread #1
Link: https://lore.kernel.org/r/20250410132850.3708703-2-ardb+git@google.com # discussion thread #2
Link: https://lore.kernel.org/r/20250417202120.1002102-2-ardb+git@google.com # final submission
2025-04-18 14:30:30 +02:00
Linus Torvalds
f4d2ef4825 Merge tag 'kbuild-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:

 - Improve performance in gendwarfksyms

 - Remove deprecated EXTRA_*FLAGS and KBUILD_ENABLE_EXTRA_GCC_CHECKS

 - Support CONFIG_HEADERS_INSTALL for ARCH=um

 - Use more relative paths to sources files for better reproducibility

 - Support the loong64 Debian architecture

 - Add Kbuild bash completion

 - Introduce intermediate vmlinux.unstripped for architectures that need
   static relocations to be stripped from the final vmlinux

 - Fix versioning in Debian packages for -rc releases

 - Treat missing MODULE_DESCRIPTION() as an error

 - Convert Nios2 Makefiles to use the generic rule for built-in DTB

 - Add debuginfo support to the RPM package

* tag 'kbuild-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (40 commits)
  kbuild: rpm-pkg: build a debuginfo RPM
  kconfig: merge_config: use an empty file as initfile
  nios2: migrate to the generic rule for built-in DTB
  rust: kbuild: skip `--remap-path-prefix` for `rustdoc`
  kbuild: pacman-pkg: hardcode module installation path
  kbuild: deb-pkg: don't set KBUILD_BUILD_VERSION unconditionally
  modpost: require a MODULE_DESCRIPTION()
  kbuild: make all file references relative to source root
  x86: drop unnecessary prefix map configuration
  kbuild: deb-pkg: add comment about future removal of KDEB_COMPRESS
  kbuild: Add a help message for "headers"
  kbuild: deb-pkg: remove "version" variable in mkdebian
  kbuild: deb-pkg: fix versioning for -rc releases
  Documentation/kbuild: Fix indentation in modules.rst example
  x86: Get rid of Makefile.postlink
  kbuild: Create intermediate vmlinux build with relocations preserved
  kbuild: Introduce Kconfig symbol for linking vmlinux with relocations
  kbuild: link-vmlinux.sh: Make output file name configurable
  kbuild: do not generate .tmp_vmlinux*.map when CONFIG_VMLINUX_MAP=y
  Revert "kheaders: Ignore silly-rename files"
  ...
2025-04-05 15:46:50 -07:00
Linus Torvalds
1fa753c7b5 Merge tag 'efi-next-for-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:

 - Decouple mixed mode startup code from the traditional x86
   decompressor

 - Revert zero-length file hack in efivarfs

 - Prevent EFI zboot from using the CopyMem/SetMem boot services after
   ExitBootServices()

 - Update EFI zboot to use the ZLIB/ZSTD library interfaces directly

* tag 'efi-next-for-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efi/libstub: Avoid legacy decompressor zlib/zstd wrappers
  efi/libstub: Avoid CopyMem/SetMem EFI services after ExitBootServices
  efi: efibc: change kmalloc(size * count, ...) to kmalloc_array()
  efivarfs: Revert "allow creation of zero length files"
  x86/efi/mixed: Move mixed mode startup code into libstub
  x86/efi/mixed: Simplify and document thunking logic
  x86/efi/mixed: Remove dependency on legacy startup_32 code
  x86/efi/mixed: Set up 1:1 mapping of lower 4GiB in the stub
  x86/efi/mixed: Factor out and clean up long mode entry
  x86/efi/mixed: Check CPU compatibility without relying on verify_cpu()
  x86/efistub: Merge PE and handover entrypoints
2025-03-29 11:36:19 -07:00
Linus Torvalds
2df0c02dab x86 boot build: make git ignore stale 'tools' directory
We've had this before: when we remove infrastructure to generate files,
the old stale build artifacts still remain in-tree.  And when the
infrastructure to generate them is gone, so is the gitignore file for
those build artifacts.

End result: git will see the old generated files, and people will
mistakenly commit them.  That's what happened with the 'genheaders' file
not that long ago (see commit 04a3389b35 "Remove stale generated
'genheaders' file").

This time it's commit 9c54baab44 ("x86/boot: Drop CRC-32 checksum and
the build tool that generates it") that removed the 'build' file from
the arch/x86/boot/tools/ subdirectory, and removed the .gitignore file
too (because the whole subdirectory is gone).

And as a result, if you don't do a 'git clean -dqfx' or similar to clean
up your tree, 'git status' will say

  Untracked files:
    (use "git add <file>..." to include in what will be committed)
	arch/x86/boot/tools/

and some hapless sleep-deprived developer will inevitably decide that
that means that they need to 'git add' that directory.  Which would
bring back some stale generated file that we most definitely do not want
in the tree.

So when removing directories that had special .gitignore patterns, make
sure to add a new gitignore entry in the parent directory for the no
longer existing subdirectory.

It will avoid mistakes.

Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Fixes: 9c54baab44 ("x86/boot: Drop CRC-32 checksum and the build tool that generates it")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2025-03-24 23:09:14 -07:00
Linus Torvalds
b58386a9bd Merge tag 'x86-boot-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 boot code updates from Ingo Molnar:

 - Memblock setup and other early boot code cleanups (Mike Rapoport)

 - Export e820_table_kexec[] to sysfs (Dave Young)

 - Baby steps of adding relocate_kernel() debugging support (David
   Woodhouse)

 - Replace open-coded parity calculation with parity8() (Kuan-Wei Chiu)

 - Move the LA57 trampoline to separate source file (Ard Biesheuvel)

 - Misc micro-optimizations (Uros Bizjak)

 - Drop obsolete E820_TYPE_RESERVED_KERN and related code (Mike
   Rapoport)

* tag 'x86-boot-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/kexec: Add relocate_kernel() debugging support: Load a GDT
  x86/boot: Move the LA57 trampoline to separate source file
  x86/boot: Do not test if AC and ID eflags are changeable on x86_64
  x86/bootflag: Replace open-coded parity calculation with parity8()
  x86/bootflag: Micro-optimize sbf_write()
  x86/boot: Add missing has_cpuflag() prototype
  x86/kexec: Export e820_table_kexec[] to sysfs
  x86/boot: Change some static bootflag functions to bool
  x86/e820: Drop obsolete E820_TYPE_RESERVED_KERN and related code
  x86/boot: Split parsing of boot_params into the parse_boot_params() helper function
  x86/boot: Split kernel resources setup into the setup_kernel_resources() helper function
  x86/boot: Move setting of memblock parameters to e820__memblock_setup()
2025-03-24 22:25:21 -07:00
Linus Torvalds
ebfb94d87b Merge tag 'x86-build-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 build updates from Ingo Molnar:

 - Drop CRC-32 checksum and the build tool that generates it (Ard
   Biesheuvel)

 - Fix broken copy command in genimage.sh when making isoimage (Nir
   Lichtman)

* tag 'x86-build-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Add back some padding for the CRC-32 checksum
  x86/boot: Drop CRC-32 checksum and the build tool that generates it
  x86/build: Fix broken copy command in genimage.sh when making isoimage
2025-03-24 22:23:23 -07:00
Thomas Weißschuh
97282e6d38 x86: drop unnecessary prefix map configuration
The toplevel Makefile already provides -fmacro-prefix-map as part of
KBUILD_CPPFLAGS. In contrast to the KBUILD_CFLAGS and KBUILD_AFLAGS
variables, KBUILD_CPPFLAGS is not redefined in the architecture specific
Makefiles. Therefore the toplevel KBUILD_CPPFLAGS do apply just fine, to
both C and ASM sources.

The custom configuration was necessary when it was added in
commit 9e2276fa6e ("arch/x86/boot: Use prefix map to avoid embedded
paths") but has since become unnecessary in commit a716bd7432
("kbuild: use -fmacro-prefix-map for .S sources").

Drop the now unnecessary custom prefix map configuration.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-03-22 23:50:58 +09:00
Thomas Huth
24a295e4ef x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-UAPI headers
While the GCC and Clang compilers already define __ASSEMBLER__
automatically when compiling assembly code, __ASSEMBLY__ is a
macro that only gets defined by the Makefiles in the kernel.

This can be very confusing when switching between userspace
and kernelspace coding, or when dealing with UAPI headers that
rather should use __ASSEMBLER__ instead. So let's standardize on
the __ASSEMBLER__ macro that is provided by the compilers now.

This is mostly a mechanical patch (done with a simple "sed -i"
statement), with some manual tweaks in <asm/frame.h>, <asm/hw_irq.h>
and <asm/setup.h> that mentioned this macro in comments with some
missing underscores.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250314071013.1575167-38-thuth@redhat.com
2025-03-19 11:47:30 +01:00
H. Peter Anvin (Intel)
841326332b x86/cpufeatures: Generate the <asm/cpufeaturemasks.h> header based on build config
Introduce an AWK script to auto-generate the <asm/cpufeaturemasks.h> header
with required and disabled feature masks based on <asm/cpufeatures.h>
and the current build config.

Thus for any CPU feature with a build config, e.g., X86_FRED, simply add:

  config X86_DISABLED_FEATURE_FRED
	def_bool y
	depends on !X86_FRED

to arch/x86/Kconfig.cpufeatures, instead of adding a conditional CPU
feature disable flag, e.g., DISABLE_FRED.

Lastly, the generated required and disabled feature masks will be added to
their corresponding feature masks for this particular compile-time
configuration.

  [ Xin: build integration improvements ]
  [ mingo: Improved changelog and comments ]

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250305184725.3341760-3-xin@zytor.com
2025-03-19 11:15:11 +01:00
Ingo Molnar
89771319e0 Merge tag 'v6.14-rc7' into x86/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2025-03-19 11:03:06 +01:00
Ard Biesheuvel
e6a03a6669 x86: Get rid of Makefile.postlink
Instead of generating the vmlinux.relocs file (needed by the
decompressor build to construct the KASLR relocation tables) as a
vmlinux postlink step, which is dubious because it depends on data that
is stripped from vmlinux before the build completes, generate it from
vmlinux.unstripped, which has been introduced specifically for this
purpose.

This ensures that each artifact is rebuilt as needed, rather than as a
side effect of another build rule.

This effectively reverts commit

  9d9173e9ce ("x86/build: Avoid relocation information in final vmlinux")

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-03-17 00:29:50 +09:00
Ard Biesheuvel
e27dffba1b x86/boot: Move the LA57 trampoline to separate source file
To permit the EFI stub to call this code even when building the kernel
without the legacy decompressor, move the trampoline out of the latter's
startup code.

This is part of an ongoing WIP effort on my part to make the existing,
generic EFI zboot format work on x86 as well.

No functional change intended.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250313120324.1095968-2-ardb+git@google.com
2025-03-13 18:12:38 +01:00
Ard Biesheuvel
e471a86a8c x86/boot: Add back some padding for the CRC-32 checksum
Even though no uses of the bzImage CRC-32 checksum are known, ensure
that the last 4 bytes of the image are unused zero bytes, so that the
checksum can be generated post-build if needed.

[ mingo: Added the 'obsolete' qualifier to the comment. ]

Suggested-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Ian Campbell <ijc@hellion.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250312081204.521411-2-ardb+git@google.com
2025-03-12 13:04:52 +01:00
Uros Bizjak
558fc8e186 x86/boot: Do not test if AC and ID eflags are changeable on x86_64
The test for the changeabitily of AC and ID EFLAGS is used to
distinguish between i386 and i486 processors (AC) and to test
for CPUID instruction support (ID).

Skip these tests on x86_64 processors as they always supports CPUID.

Also change the return type of has_eflag() to bool.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20250307091022.181136-1-ubizjak@gmail.com
2025-03-08 20:36:26 +01:00
Ard Biesheuvel
9c54baab44 x86/boot: Drop CRC-32 checksum and the build tool that generates it
Apart from some sanity checks on the size of setup.bin, the only
remaining task carried out by the arch/x86/boot/tools/build.c build tool
is generating the CRC-32 checksum of the bzImage. This feature was added
in commit

  7d6e737c8d ("x86: add a crc32 checksum to the kernel image.")

without any motivation (or any commit log text, for that matter). This
checksum is not verified by any known bootloader, and given that

 a) the checksum of the entire bzImage is reported by most tools (zlib,
    rhash) as 0xffffffff and not 0x0 as documented,

 b) the checksum is corrupted when the image is signed for secure boot,
    which means that no distro ships x86 images with valid CRCs,

it seems quite unlikely that this checksum is being used, so let's just
drop it, along with the tool that generates it.

Instead, use simple file concatenation and truncation to combine the two
pieces into bzImage, and replace the checks on the size of the setup
block with a couple of ASSERT()s in the linker script.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ian Campbell <ijc@hellion.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250307164801.885261-2-ardb+git@google.com
2025-03-07 23:59:10 +01:00
Ard Biesheuvel
48140f8bca Merge branch 'x86-mixed-mode' into efi/next 2025-03-07 12:30:53 +01:00
Ard Biesheuvel
c00b413a96 x86/boot: Sanitize boot params before parsing command line
The 5-level paging code parses the command line to look for the 'no5lvl'
string, and does so very early, before sanitize_boot_params() has been
called and has been given the opportunity to wipe bogus data from the
fields in boot_params that are not covered by struct setup_header, and
are therefore supposed to be initialized to zero by the bootloader.

This triggers an early boot crash when using syslinux-efi to boot a
recent kernel built with CONFIG_X86_5LEVEL=y and CONFIG_EFI_STUB=n, as
the 0xff padding that now fills the unused PE/COFF header is copied into
boot_params by the bootloader, and interpreted as the top half of the
command line pointer.

Fix this by sanitizing the boot_params before use. Note that there is no
harm in calling this more than once; subsequent invocations are able to
spot that the boot_params have already been cleaned up.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@vger.kernel.org> # v6.1+
Link: https://lore.kernel.org/r/20250306155915.342465-2-ardb+git@google.com
Closes: https://lore.kernel.org/all/202503041549.35913.ulrich.gemkow@ikr.uni-stuttgart.de
2025-03-06 22:02:39 +01:00
Zhou Ding
7d8f03f7dd x86/boot: Add missing has_cpuflag() prototype
We get a warning when building the kernel with W=1:

  arch/x86/boot/compressed/cpuflags.c:4:6: warning: no previous prototype for ‘has_cpuflag’ [-Werror=missing-prototypes]
      4 | bool has_cpuflag(int flag)
        |      ^~~~~~~~~~~

Add a function declaration to cpuflags.h

Signed-off-by: Zhou Ding <zhouding@cmss.chinamobile.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20241217162859.1167889-1-zhouding@cmss.chinamobile.com
2025-02-26 15:40:23 +01:00
Nir Lichtman
e451630226 x86/build: Fix broken copy command in genimage.sh when making isoimage
Problem: Currently when running the "make isoimage" command there is an
error related to wrong parameters passed to the cp command:

  "cp: missing destination file operand after 'arch/x86/boot/isoimage/'"

This is caused because FDINITRDS is an empty array.

Solution: Check if FDINITRDS is empty before executing the "cp" command,
similar to how it is done in the case of hdimage.

Signed-off-by: Nir Lichtman <nir@lichtman.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michal Marek <michal.lkml@markovi.net>
Link: https://lore.kernel.org/r/20250110120500.GA923218@lichtman.org
2025-02-25 21:13:33 +01:00
Ard Biesheuvel
fb84cefd4c x86/efi/mixed: Move mixed mode startup code into libstub
The EFI mixed mode code has been decoupled from the legacy decompressor,
in order to be able to reuse it with generic EFI zboot images for x86.

Move the source file into the libstub source directory to facilitate
this.

Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2025-02-21 16:54:39 +01:00
Ard Biesheuvel
b891e4209c x86/efi/mixed: Simplify and document thunking logic
Now that the GDT/IDT and data segment selector preserve/restore logic
has been removed from the boot-time EFI mixed mode thunking routines,
the remaining logic to handle the function arguments can be simplified:
the setup of the arguments on the stack can be moved into the 32-bit
callee, which is able to use a more idiomatic sequence of PUSH
instructions.

This, in turn, allows the far call and far return to be issued using
plain LCALL and LRET instructions, removing the need to set up the
return explicitly.

Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2025-02-21 16:54:35 +01:00
Ard Biesheuvel
6e2da8d87c x86/efi/mixed: Remove dependency on legacy startup_32 code
The EFI mixed mode startup code calls into startup_32 in the legacy
decompressor with a mocked up boot_params struct, only to get it to set
up the 1:1 mapping of the lower 4 GiB of memory and switch to a GDT that
supports 64-bit mode.

In order to be able to reuse the EFI mixed mode startup code in EFI
zboot images, which do not incorporate the legacy decompressor code,
decouple it, by dealing with the GDT and IDT directly.

Doing so makes it possible to construct a GDT that is compatible with
the one the firmware uses, with one additional entry for a 64-bit mode
code segment appended. This removes the need entirely to switch between
GDTs and IDTs or data segment selector values and all of this code can
be removed.

Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2025-02-21 16:54:31 +01:00
Ard Biesheuvel
d545e182a8 x86/efi/mixed: Set up 1:1 mapping of lower 4GiB in the stub
In preparation for dropping the dependency on startup_32 entirely in the
next patch, add the code that sets up the 1:1 mapping of the lower 4 GiB
of system RAM to the mixed mode stub.

The reload of CR3 after the long mode switch will be removed in a
subsequent patch, when it is no longer needed.

Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2025-02-21 16:54:27 +01:00
Ard Biesheuvel
ff38bbbac3 x86/efi/mixed: Factor out and clean up long mode entry
Entering long mode involves setting the EFER_LME and CR4.PAE bits before
enabling paging by setting CR0.PG bit.

It also involves disabling interrupts, given that the firmware's 32-bit
IDT becomes invalid as soon as the CPU transitions into long mode.

Reloading the CR3 register is not necessary at boot time, given that the
EFI firmware as well as the kernel's EFI stub use a 1:1 mapping of the
32-bit addressable memory in the system.

Break out this code into a separate helper for clarity, and so that it
can be reused in a subsequent patch.

Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2025-02-21 16:54:21 +01:00
Ard Biesheuvel
eaed895595 x86/efi/mixed: Check CPU compatibility without relying on verify_cpu()
In order for the EFI mixed mode startup code to be reusable in a context
where the legacy decompressor is not used, replace the call to
verify_cpu() [which performs an elaborate set of checks] with a simple
check against the 'long mode' bit in the appropriate CPUID leaf.

This is reasonable, given that EFI support is implied when booting in
this manner, and so there is no need to consider very old CPUs when
performing this check.

Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2025-02-21 16:54:16 +01:00
Ard Biesheuvel
dac628e956 x86/efistub: Merge PE and handover entrypoints
The difference between the PE and handover entrypoints in the EFI stub
is that the former allocates a struct boot_params whereas the latter
expects one from the caller. Currently, these are two completely
separate entrypoints, duplicating some logic and both relying of
efi_exit() to return straight back to the firmware on an error.

Simplify this by making the PE entrypoint call the handover entrypoint
with NULL as the argument for the struct boot_params parameter. This
makes the code easier to follow, and removes the need to support two
different calling conventions in the mixed mode asm code.

While at it, move the assignment of boot_params_ptr into the function
that actually calls into the legacy decompressor, which is where its
value is required.

Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2025-02-21 16:54:05 +01:00
Brian Gerst
a8327be7b2 x86/boot/64: Remove inverse relocations
Inverse relocations were needed to offset the effects of relocation for
RIP-relative accesses to zero-based percpu data.  Now that the percpu
section is linked normally as part of the kernel image, they are no
longer needed.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250123190747.745588-11-brgerst@gmail.com
2025-02-18 10:15:47 +01:00
Nathan Chancellor
ee2ab467bd x86/boot: Use '-std=gnu11' to fix build with GCC 15
GCC 15 changed the default C standard version to C23, which should not
have impacted the kernel because it requests the gnu11 standard via
'-std=' in the main Makefile. However, the x86 compressed boot Makefile
uses its own set of KBUILD_CFLAGS without a '-std=' value (i.e., using
the default), resulting in errors from the kernel's definitions of bool,
true, and false in stddef.h, which are reserved keywords under C23.

  ./include/linux/stddef.h:11:9: error: expected identifier before ‘false’
     11 |         false   = 0,
  ./include/linux/types.h:35:33: error: two or more data types in declaration specifiers
     35 | typedef _Bool                   bool;

Set '-std=gnu11' in the x86 compressed boot Makefile to resolve the
error and consistently use the same C standard version for the entire
kernel.

Closes: https://lore.kernel.org/4OAhbllK7x4QJGpZjkYjtBYNLd_2whHx9oFiuZcGwtVR4hIzvduultkgfAIRZI3vQpZylu7Gl929HaYFRGeMEalWCpeMzCIIhLxxRhq4U-Y=@protonmail.com/
Closes: https://lore.kernel.org/Z4467umXR2PZ0M1H@tucnak/
Reported-by: Kostadin Shishmanov <kostadinshishmanov@protonmail.com>
Reported-by: Jakub Jelinek <jakub@redhat.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/20250121-x86-use-std-consistently-gcc-15-v1-1-8ab0acf645cb%40kernel.org
2025-01-30 09:59:24 -08:00
Linus Torvalds
858df1de21 Merge tag 'x86-cleanups-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cleanups from Ingo Molnar:
 "Miscellaneous x86 cleanups and typo fixes, and also the removal of
  the 'disablelapic' boot parameter"

* tag 'x86-cleanups-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/ioapic: Remove a stray tab in the IO-APIC type string
  x86/cpufeatures: Remove "AMD" from the comments to the AMD-specific leaf
  Documentation/kernel-parameters: Fix a typo in kvm.enable_virt_at_load text
  x86/cpu: Fix typo in x86_match_cpu()'s doc
  x86/apic: Remove "disablelapic" cmdline option
  Documentation: Merge x86-specific boot options doc into kernel-parameters.txt
  x86/ioremap: Remove unused size parameter in remapping functions
  x86/ioremap: Simplify setup_data mapping variants
  x86/boot/compressed: Remove unused header includes from kaslr.c
2025-01-21 11:15:29 -08:00
Nikunj A Dadhania
0563ee35ae x86/sev: Add the Secure TSC feature for SNP guests
Now that all the required plumbing is done for enabling Secure TSC, add it to
the SNP features present list.

Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Peter Gonda <pgonda@google.com>
Link: https://lore.kernel.org/r/20250106124633.1418972-14-nikunj@amd.com
2025-01-09 10:21:56 +01:00
Borislav Petkov (AMD)
5daececd4f x86/boot/compressed: Remove unused header includes from kaslr.c
Nothing is using the linux/ namespace headers anymore. Remove them.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20241130122644.GAZ0sEhD3Bm_9ZAIuc@fat_crate.local
2024-12-02 16:44:32 +01:00
Linus Torvalds
89c45f3823 Merge tag 'x86-cleanups-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cleanups from Ingo Molnar:

 - x86/boot: Remove unused function atou() (Dr. David Alan Gilbert)

 - x86/cpu: Use str_yes_no() helper in show_cpuinfo_misc() (Thorsten
   Blum)

 - x86/platform: Switch back to struct platform_driver::remove() (Uwe
   Kleine-König)

* tag 'x86-cleanups-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Remove unused function atou()
  x86/cpu: Use str_yes_no() helper in show_cpuinfo_misc()
  x86/platform: Switch back to struct platform_driver::remove()
2024-11-19 14:46:39 -08:00
Dr. David Alan Gilbert
97ecb260d9 x86/boot: Remove unused function atou()
I can't find any sign of atou() having been used. Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240913005753.1392431-1-linux@treblig.org
2024-11-07 18:08:23 +01:00
Ashish Kalra
f30470c190 x86/boot: Skip video memory access in the decompressor for SEV-ES/SNP
Accessing guest video memory/RAM in the decompressor causes guest
termination as the boot stage2 #VC handler for SEV-ES/SNP systems does
not support MMIO handling.

This issue is observed during a SEV-ES/SNP guest kexec as kexec -c adds
screen_info to the boot parameters passed to the second kernel, which
causes console output to be dumped to both video and serial.

As the decompressor output gets cleared really fast, it is preferable to
get the console output only on serial, hence, skip accessing the video
RAM during decompressor stage to prevent guest termination.

Serial console output during decompressor stage works as boot stage2 #VC
handler already supports handling port I/O.

  [ bp: Massage. ]

Suggested-by: Borislav Petkov (AMD) <bp@alien8.de>
Suggested-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/8a55ea86524c686e575d273311acbe57ce8cee23.1722520012.git.ashish.kalra@amd.com
2024-10-28 16:54:16 +01:00
Kirill A. Shutemov
5adfeaecc4 mm: rework accept memory helpers
Make accept_memory() and range_contains_unaccepted_memory() take 'start'
and 'size' arguments instead of 'start' and 'end'.

Remove accept_page(), replacing it with direct calls to accept_memory(). 
The accept_page() name is going to be used for a different function.

Link: https://lkml.kernel.org/r/20240809114854.3745464-6-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:26:07 -07:00
Linus Torvalds
ca83c61cb3 Merge tag 'kbuild-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:

 - Remove tristate choice support from Kconfig

 - Stop using the PROVIDE() directive in the linker script

 - Reduce the number of links for the combination of CONFIG_KALLSYMS and
   CONFIG_DEBUG_INFO_BTF

 - Enable the warning for symbol reference to .exit.* sections by
   default

 - Fix warnings in RPM package builds

 - Improve scripts/make_fit.py to generate a FIT image with separate
   base DTB and overlays

 - Improve choice value calculation in Kconfig

 - Fix conditional prompt behavior in choice in Kconfig

 - Remove support for the uncommon EMAIL environment variable in Debian
   package builds

 - Remove support for the uncommon "name <email>" form for the DEBEMAIL
   environment variable

 - Raise the minimum supported GNU Make version to 4.0

 - Remove stale code for the absolute kallsyms

 - Move header files commonly used for host programs to scripts/include/

 - Introduce the pacman-pkg target to generate a pacman package used in
   Arch Linux

 - Clean up Kconfig

* tag 'kbuild-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (65 commits)
  kbuild: doc: gcc to CC change
  kallsyms: change sym_entry::percpu_absolute to bool type
  kallsyms: unify seq and start_pos fields of struct sym_entry
  kallsyms: add more original symbol type/name in comment lines
  kallsyms: use \t instead of a tab in printf()
  kallsyms: avoid repeated calculation of array size for markers
  kbuild: add script and target to generate pacman package
  modpost: use generic macros for hash table implementation
  kbuild: move some helper headers from scripts/kconfig/ to scripts/include/
  Makefile: add comment to discourage tools/* addition for kernel builds
  kbuild: clean up scripts/remove-stale-files
  kconfig: recursive checks drop file/lineno
  kbuild: rpm-pkg: introduce a simple changelog section for kernel.spec
  kallsyms: get rid of code for absolute kallsyms
  kbuild: Create INSTALL_PATH directory if it does not exist
  kbuild: Abort make on install failures
  kconfig: remove 'e1' and 'e2' macros from expression deduplication
  kconfig: remove SYMBOL_CHOICEVAL flag
  kconfig: add const qualifiers to several function arguments
  kconfig: call expr_eliminate_yn() at least once in expr_eliminate_dups()
  ...
2024-07-23 14:32:21 -07:00
Zhang Bingwu
af7925d820 kbuild: Abort make on install failures
Setting '-e' flag tells shells to exit with error exit code immediately
after any of commands fails, and causes make(1) to regard recipes as
failed.

Before this, make will still continue to succeed even after the
installation failed, for example, for insufficient permission or
directory does not exist.

Signed-off-by: Zhang Bingwu <xtexchooser@duck.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-07-20 13:34:54 +09:00
Linus Torvalds
e55037c879 Merge tag 'efi-next-for-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:
 "Note the removal of the EFI fake memory map support - this is believed
  to be unused and no longer worth supporting. However, we could easily
  bring it back if needed.

  With recent developments regarding confidential VMs and unaccepted
  memory, combined with kexec, creating a known inaccurate view of the
  firmware's memory map and handing it to the OS is a feature we can
  live without, hence the removal. Alternatively, I could imagine making
  this feature mutually exclusive with those confidential VM related
  features, but let's try simply removing it first.

  Summary:

   - Drop support for the 'fake' EFI memory map on x86

   - Add an SMBIOS based tweak to the EFI stub instructing the firmware
     on x86 Macbook Pros to keep both GPUs enabled

   - Replace 0-sized array with flexible array in EFI memory attributes
     table handling

   - Drop redundant BSS clearing when booting via the native PE
     entrypoint on x86

   - Avoid returning EFI_SUCCESS when aborting on an out-of-memory
     condition

   - Cosmetic tweak for arm64 KASLR loading logic"

* tag 'efi-next-for-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efi: Replace efi_memory_attributes_table_t 0-sized array with flexible array
  efi: Rename efi_early_memdesc_ptr() to efi_memdesc_ptr()
  arm64/efistub: Clean up KASLR logic
  x86/efistub: Drop redundant clearing of BSS
  x86/efistub: Avoid returning EFI_SUCCESS on error
  x86/efistub: Call Apple set_os protocol on dual GPU Intel Macs
  x86/efistub: Enable SMBIOS protocol handling for x86
  efistub/smbios: Simplify SMBIOS enumeration API
  x86/efi: Drop support for fake EFI memory maps
2024-07-16 12:22:07 -07:00
Linus Torvalds
408323581b Merge tag 'x86_sev_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 SEV updates from Borislav Petkov:

 - Add support for running the kernel in a SEV-SNP guest, over a Secure
   VM Service Module (SVSM).

   When running over a SVSM, different services can run at different
   protection levels, apart from the guest OS but still within the
   secure SNP environment. They can provide services to the guest, like
   a vTPM, for example.

   This series adds the required facilities to interface with such a
   SVSM module.

 - The usual fixlets, refactoring and cleanups

[ And as always: "SEV" is AMD's "Secure Encrypted Virtualization".

  I can't be the only one who gets all the newer x86 TLA's confused,
  can I?
              - Linus ]

* tag 'x86_sev_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Documentation/ABI/configfs-tsm: Fix an unexpected indentation silly
  x86/sev: Do RMP memory coverage check after max_pfn has been set
  x86/sev: Move SEV compilation units
  virt: sev-guest: Mark driver struct with __refdata to prevent section mismatch
  x86/sev: Allow non-VMPL0 execution when an SVSM is present
  x86/sev: Extend the config-fs attestation support for an SVSM
  x86/sev: Take advantage of configfs visibility support in TSM
  fs/configfs: Add a callback to determine attribute visibility
  sev-guest: configfs-tsm: Allow the privlevel_floor attribute to be updated
  virt: sev-guest: Choose the VMPCK key based on executing VMPL
  x86/sev: Provide guest VMPL level to userspace
  x86/sev: Provide SVSM discovery support
  x86/sev: Use the SVSM to create a vCPU when not in VMPL0
  x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0
  x86/sev: Use kernel provided SVSM Calling Areas
  x86/sev: Check for the presence of an SVSM in the SNP secrets page
  x86/irqflags: Provide native versions of the local_irq_save()/restore()
2024-07-16 11:12:25 -07:00
Linus Torvalds
d679783188 Merge tag 'x86_cpu_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu model updates from Borislav Petkov:

 - Flip the logic to add feature names to /proc/cpuinfo to having to
   explicitly specify the flag if there's a valid reason to show it in
   /proc/cpuinfo

 - Switch a bunch of Intel x86 model checking code to the new CPU model
   defines

 - Fixes and cleanups

* tag 'x86_cpu_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu/intel: Drop stray FAM6 check with new Intel CPU model defines
  x86/cpufeatures: Flip the /proc/cpuinfo appearance logic
  x86/CPU/AMD: Always inline amd_clear_divider()
  x86/mce/inject: Add missing MODULE_DESCRIPTION() line
  perf/x86/rapl: Switch to new Intel CPU model defines
  x86/boot: Switch to new Intel CPU model defines
  x86/cpu: Switch to new Intel CPU model defines
  perf/x86/intel: Switch to new Intel CPU model defines
  x86/virt/tdx: Switch to new Intel CPU model defines
  x86/PCI: Switch to new Intel CPU model defines
  x86/cpu/intel: Switch to new Intel CPU model defines
  x86/platform/intel-mid: Switch to new Intel CPU model defines
  x86/pconfig: Remove unused MKTME pconfig code
  x86/cpu: Remove useless work in detect_tme_early()
2024-07-15 20:25:16 -07:00
Linus Torvalds
181a984b7d Merge tag 'x86_cleanups_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cleanups from Borislav Petkov:

 - Remove an unused function and the documentation of an already removed
   cmdline parameter

* tag 'x86_cleanups_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Remove unused function __fortify_panic()
  Documentation: Remove "mfgpt_irq=" from the kernel-parameters.txt file
2024-07-15 19:34:20 -07:00
Linus Torvalds
4578d072fa Merge tag 'x86_boot_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 boot updates from Borislav Petkov:

 - Add a check to warn when cmdline parsing happens before the final
   cmdline string has been built and thus arguments can get lost

 - Code cleanups and simplifications

* tag 'x86_boot_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/setup: Warn when option parsing is done too early
  x86/boot: Clean up the arch/x86/boot/main.c code a bit
  x86/boot: Use current_stack_pointer to avoid asm() in init_heap()
2024-07-15 19:31:59 -07:00
Borislav Petkov (AMD)
38918e0bb2 x86/sev: Move SEV compilation units
A long time ago it was agreed upon that the coco stuff needs to go where
it belongs:

  https://lore.kernel.org/all/Yg5nh1RknPRwIrb8@zn.tnic

and not keep it in arch/x86/kernel. TDX did that and SEV can't find time
to do so. So lemme do it. If people have trouble converting their
ongoing featuritis patches, ask me for a sed script.

No functional changes.

Move the instrumentation exclusion bits too, as helpfully caught and
reported by the 0day folks.

Closes: https://lore.kernel.org/oe-kbuild-all/202406220748.hG3qlmDx-lkp@intel.com
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202407091342.46d7dbb-oliver.sang@intel.com
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Reviewed-by: Ashish Kalra <ashish.kalra@amd.com>
Tested-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/r/20240619093014.17962-1-bp@kernel.org
2024-07-11 11:55:58 +02:00
Ard Biesheuvel
37aee82c21 x86/efi: Drop support for fake EFI memory maps
Between kexec and confidential VM support, handling the EFI memory maps
correctly on x86 is already proving to be rather difficult (as opposed
to other EFI architectures which manage to never modify the EFI memory
map to begin with)

EFI fake memory map support is essentially a development hack (for
testing new support for the 'special purpose' and 'more reliable' EFI
memory attributes) that leaked into production code. The regions marked
in this manner are not actually recognized as such by the firmware
itself or the EFI stub (and never have), and marking memory as 'more
reliable' seems rather futile if the underlying memory is just ordinary
RAM.

Marking memory as 'special purpose' in this way is also dubious, but may
be in use in production code nonetheless. However, the same should be
achievable by using the memmap= command line option with the ! operator.

EFI fake memmap support is not enabled by any of the major distros
(Debian, Fedora, SUSE, Ubuntu) and does not exist on other
architectures, so let's drop support for it.

Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2024-07-02 00:26:24 +02:00
Tom Lendacky
99ef9f5984 x86/sev: Allow non-VMPL0 execution when an SVSM is present
To allow execution at a level other than VMPL0, an SVSM must be present.
Allow the SEV-SNP guest to continue booting if an SVSM is detected and
the hypervisor supports the SVSM feature as indicated in the GHCB
hypervisor features bitmap.

  [ bp: Massage a bit. ]

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/2ce7cf281cce1d0cba88f3f576687ef75dc3c953.1717600736.git.thomas.lendacky@amd.com
2024-06-17 20:42:58 +02:00
Tom Lendacky
fcd042e864 x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0
The PVALIDATE instruction can only be performed at VMPL0. If an SVSM is
present, it will be running at VMPL0 while the guest itself is then
running at VMPL1 or a lower privilege level.

In that case, use the SVSM_CORE_PVALIDATE call to perform memory
validation instead of issuing the PVALIDATE instruction directly.

The validation of a single 4K page is now explicitly identified as such
in the function name, pvalidate_4k_page(). The pvalidate_pages()
function is used for validating 1 or more pages at either 4K or 2M in
size. Each function, however, determines whether it can issue the
PVALIDATE directly or whether the SVSM needs to be invoked.

  [ bp: Touchups. ]
  [ Tom: fold in a fix for Coconut SVSM:
    https://lore.kernel.org/r/234bb23c-d295-76e5-a690-7ea68dc1118b@amd.com  ]

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/4c4017d8b94512d565de9ccb555b1a9f8983c69c.1717600736.git.thomas.lendacky@amd.com
2024-06-17 20:37:54 +02:00
Nikolay Borisov
71315037cb x86/boot: Remove unused function __fortify_panic()
That function is only used when the kernel is compiled with FORTIFY_SOURCE and
when the kernel proper string.h header is used. The decompressor code doesn't
use the kernel proper header but has local copy which doesn't contain any
fortified implementations of the various string functions. As such
__fortify_panic() can never be called from the decompressor so remove it.

Signed-off-by: Nikolay Borisov <nik.borisov@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240613110837.300273-1-nik.borisov@suse.com
2024-06-14 18:08:45 +02:00
Benjamin Segall
b2747f108b x86/boot: Don't add the EFI stub to targets, again
This is a re-commit of

  da05b143a3 ("x86/boot: Don't add the EFI stub to targets")

after the tagged patch incorrectly reverted it.

vmlinux-objs-y is added to targets, with an assumption that they are all
relative to $(obj); adding a $(objtree)/drivers/...  path causes the
build to incorrectly create a useless
arch/x86/boot/compressed/drivers/...  directory tree.

Fix this just by using a different make variable for the EFI stub.

Fixes: cb8bda8ad4 ("x86/boot/compressed: Rename efi_thunk_64.S to efi-mixed.S")
Signed-off-by: Ben Segall <bsegall@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: stable@vger.kernel.org # v6.1+
Link: https://lore.kernel.org/r/xm267ceukksz.fsf@bsegall.svl.corp.google.com
2024-06-13 10:32:36 +02:00