lwn.git/arch/x86/boot/compressed, branch master

Merge tag 'x86_sev_for_v7.1_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-04-14T22:20:54+00:00

Pull x86 SEV updates from Borislav Petkov: - Change the SEV host code handling of when SNP gets enabled in order to allow the machine to claim SNP-related resources only when SNP guests are really going to be launched. The user requests this by loading the ccp module and thus it controls when SNP initialization is done So export an API which module code can call and do the necessary SNP setup only when really needed - Drop an unnecessary write-back and invalidate operation that was being performed too early, since the ccp driver already issues its own at the correct point in the initialization sequence - Drop the hotplug callbacks for enabling SNP on newly onlined CPUs, which were both architecturally unsound (the firmware rejects initialization if any CPU lacks the required configuration) and buggy (the MFDM SYSCFG MSR bit was not being set) - Code refactoring and cleanups to accomplish the above * tag 'x86_sev_for_v7.1_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: crypto/ccp: Update HV_FIXED page states to allow freeing of memory crypto/ccp: Implement SNP x86 shutdown x86/sev, crypto/ccp: Move HSAVE_PA setup to arch/x86/ x86/sev, crypto/ccp: Move SNP init to ccp driver x86/sev: Create snp_shutdown() x86/sev: Create snp_prepare() x86/sev: Create a function to clear/zero the RMP x86/sev: Rename SNP_FEATURES_PRESENT to SNP_FEATURES_IMPL x86/virt/sev: Keep the RMP table bookkeeping area mapped x86/virt/sev: Drop WBINVD before setting MSR_AMD64_SYSCFG_SNP_EN x86/virt/sev: Drop support for SNP hotplug

Merge tag 'kbuild-7.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux

2026-04-14T16:18:40+00:00

Pull Kbuild/Kconfig updates from Nicolas Schier: "Kbuild: - reject unexpected values for LLVM= - uapi: remove usage of toolchain headers - switch from '-fms-extensions' to '-fms-anonymous-structs' when available (currently: clang >= 23.0.0) - reduce the number of compiler-generated suffixes for clang thin-lto build - reduce output spam ("GEN Makefile") when building out of tree - improve portability for testing headers - also test UAPI headers against C++ compilers - drop build ID architecture allow-list in vdso_install - only run checksyscalls when necessary - update the debug information notes in reproducible-builds.rst - expand inlining hints with -fdiagnostics-show-inlining-chain Kconfig: - forbid multiple entries with the same symbol in a choice - error out on duplicated kconfig inclusion" * tag 'kbuild-7.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (35 commits) kbuild: expand inlining hints with -fdiagnostics-show-inlining-chain kconfig: forbid multiple entries with the same symbol in a choice Documentation: kbuild: Update the debug information notes in reproducible-builds.rst checksyscalls: move instance functionality into generic code checksyscalls: only run when necessary checksyscalls: fail on all intermediate errors checksyscalls: move path to reference table to a variable kbuild: vdso_install: drop build ID architecture allow-list kbuild: vdso_install: gracefully handle images without build ID kbuild: vdso_install: hide readelf warnings kbuild: vdso_install: split out the readelf invocation kbuild: uapi: also test UAPI headers against C++ compilers kbuild: uapi: provide a C++ compatible dummy definition of NULL kbuild: uapi: handle UML in architecture-specific exclusion lists kbuild: uapi: move all include path flags together kbuild: uapi: move some compiler arguments out of the command definition check-uapi: use dummy libc includes check-uapi: honor ${CROSS_COMPILE} setting check-uapi: link into shared objects kbuild: reduce output spam when building out of tree ...

x86/sev: Rename SNP_FEATURES_PRESENT to SNP_FEATURES_IMPL

2026-03-16T20:08:50+00:00

Rename SNP_FEATURES_PRESENT to SNP_FEATURES_IMPL to denote its counterpart relationship with SNP_FEATURES_IMPL_REQ. [ bp: Drop stable@, massage commit message. ] Suggested-by: Borislav Petkov (AMD) Suggested-by: Tom Lendacky Signed-off-by: Kim Phillips Signed-off-by: Borislav Petkov (AMD) Link: https://patch.msgid.link/20260203222405.4065706-4-kim.phillips@amd.com

kbuild: Consolidate C dialect options

2026-03-12T11:52:37+00:00

Introduce CC_FLAGS_DIALECT to make it easier to update the various places in the tree that rely on the GNU C standard and Microsoft extensions flags atomically. All remaining uses of '-std=gnu11' and '-fms-extensions' are in the tools directory (which has its own build system) and other standalone Makefiles. This will allow the kernel to use a narrower option to enable the Microsoft anonymous tagged structure extension in a simpler manner. Place the CC_FLAGS_DIALECT block after the configuration include (so that a future change can move the selection of the flag to Kconfig) but before the arch/$(SRCARCH)/Makefile include (so that CC_FLAGS_DIALECT is available for use in those Makefiles). Signed-off-by: Nathan Chancellor Reviewed-by: Nicolas Schier Acked-by: Ard Biesheuvel Acked-by: Helge Deller # parisc Link: https://patch.msgid.link/20260223-fms-anonymous-structs-v1-1-8ee406d3c36c@kernel.org Signed-off-by: Nicolas Schier

Merge tag 'x86-urgent-2026-03-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-03-08T01:12:06+00:00

Pull x86 fixes from Ingo Molnar: - Fix SEV guest boot failures in certain circumstances, due to very early code relying on a BSS-zeroed variable that isn't actually zeroed yet an may contain non-zero bootup values Move the variable into the .data section go gain even earlier zeroing - Expose & allow the IBPB-on-Entry feature on SNP guests, which was not properly exposed to guests due to initial implementational caution - Fix O= build failure when CONFIG_EFI_SBAT_FILE is using relative file paths - Fix the various SNC (Sub-NUMA Clustering) topology enumeration bugs/artifacts (sched-domain build errors mostly). SNC enumeration data got more complicated with Granite Rapids X (GNR) and Clearwater Forest X (CWF), which exposed these bugs and made their effects more serious - Also use the now sane(r) SNC code to fix resctrl SNC detection bugs - Work around a historic libgcc unwinder bug in the vdso32 sigreturn code (again), which regressed during an overly aggressive recent cleanup of DWARF annotations * tag 'x86-urgent-2026-03-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/entry/vdso32: Work around libgcc unwinder bug x86/resctrl: Fix SNC detection x86/topo: Fix SNC topology mess x86/topo: Replace x86_has_numa_in_package x86/topo: Add topology_num_nodes_per_package() x86/numa: Store extra copy of numa_nodes_parsed x86/boot: Handle relative CONFIG_EFI_SBAT_FILE file paths x86/sev: Allow IBPB-on-Entry feature for SNP guests x86/boot/sev: Move SEV decompressor variables into the .data section

x86/boot: Handle relative CONFIG_EFI_SBAT_FILE file paths

2026-03-04T10:51:08+00:00

CONFIG_EFI_SBAT_FILE can be a relative path. When compiling using a different output directory (O=) the build currently fails because it can't find the filename set in CONFIG_EFI_SBAT_FILE: arch/x86/boot/compressed/sbat.S: Assembler messages: arch/x86/boot/compressed/sbat.S:6: Error: file not found: kernel.sbat Add $(srctree) as include dir for sbat.o. [ bp: Massage commit message. ] Fixes: 61b57d35396a ("x86/efi: Implement support for embedding SBAT data for x86") Signed-off-by: Jan Stancek Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Vitaly Kuznetsov Cc: Link: https://patch.msgid.link/f4eda155b0cef91d4d316b4e92f5771cb0aa7187.1772047658.git.jstancek@redhat.com

x86/sev: Allow IBPB-on-Entry feature for SNP guests

2026-03-02T10:08:59+00:00

The SEV-SNP IBPB-on-Entry feature does not require a guest-side implementation. It was added in Zen5 h/w, after the first SNP Zen implementation, and thus was not accounted for when the initial set of SNP features were added to the kernel. In its abundant precaution, commit 8c29f0165405 ("x86/sev: Add SEV-SNP guest feature negotiation support") included SEV_STATUS' IBPB-on-Entry bit as a reserved bit, thereby masking guests from using the feature. Allow guests to make use of IBPB-on-Entry when supported by the hypervisor, as the bit is now architecturally defined and safe to expose. Fixes: 8c29f0165405 ("x86/sev: Add SEV-SNP guest feature negotiation support") Signed-off-by: Kim Phillips Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Nikunj A Dadhania Reviewed-by: Tom Lendacky Cc: stable@kernel.org Link: https://patch.msgid.link/20260203222405.4065706-2-kim.phillips@amd.com

x86/boot/sev: Move SEV decompressor variables into the .data section

2026-03-02T10:08:33+00:00

As part of the work to remove the dependency on calling into the decompressor code (startup_64()) for a UEFI boot, a call to rmpadjust() was removed from sev_enable() in favor of checking the value of the snp_vmpl variable. When booting through a non-UEFI path and calling startup_64(), the call to sev_enable() is performed before the BSS section is zeroed. With the removal of the rmpadjust() call and the corresponding check of the return code, the snp_vmpl variable is checked. Since the kernel is running at VMPL0, the snp_vmpl variable will not have been set and should be the default value of 0. However, since the call occurs before the BSS is zeroed, the snp_vmpl variable may not actually be zero, which will cause the guest boot to fail. Since the decompressor relocates itself, the BSS would need to be cleared both before and after the relocation, but this would, in effect, cause all of the changes to BSS variables before relocation to be lost after relocation. Instead, move the snp_vmpl variable into the .data section so that it is initialized and the value made safe during relocation. As a pre-caution against future changes, move other SEV-related decompressor variables into the .data section, too. Fixes: 68a501d7fd82 ("x86/boot: Drop redundant RMPADJUST in SEV SVSM presence check") Signed-off-by: Tom Lendacky Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Ard Biesheuvel Reviewed-by: Changyuan Lyu Tested-by: Kevin Hui Tested-by: Changyuan Lyu Cc: stable@vger.kernel.org Link: https://patch.msgid.link/5648b7de5b0a5d0dfef3785f9582b718678c6448.1770217260.git.thomas.lendacky@amd.com

kbuild: Split .modinfo out from ELF_DETAILS

2026-02-26T18:50:19+00:00

Commit 3e86e4d74c04 ("kbuild: keep .modinfo section in vmlinux.unstripped") added .modinfo to ELF_DETAILS while removing it from COMMON_DISCARDS, as it was needed in vmlinux.unstripped and ELF_DETAILS was present in all architecture specific vmlinux linker scripts. While this shuffle is fine for vmlinux, ELF_DETAILS and COMMON_DISCARDS may be used by other linker scripts, such as the s390 and x86 compressed boot images, which may not expect to have a .modinfo section. In certain circumstances, this could result in a bootloader failing to load the compressed kernel [1]. Commit ddc6cbef3ef1 ("s390/boot/vmlinux.lds.S: Ensure bzImage ends with SecureBoot trailer") recently addressed this for the s390 bzImage but the same bug remains for arm, parisc, and x86. The presence of .modinfo in the x86 bzImage was the root cause of the issue worked around with commit d50f21091358 ("kbuild: align modinfo section for Secureboot Authenticode EDK2 compat"). misc.c in arch/x86/boot/compressed includes lib/decompress_unzstd.c, which in turn includes lib/xxhash.c and its MODULE_LICENSE / MODULE_DESCRIPTION macros due to the STATIC definition. Split .modinfo out from ELF_DETAILS into its own macro and handle it in all vmlinux linker scripts. Discard .modinfo in the places where it was previously being discarded from being in COMMON_DISCARDS, as it has never been necessary in those uses. Cc: stable@vger.kernel.org Fixes: 3e86e4d74c04 ("kbuild: keep .modinfo section in vmlinux.unstripped") Reported-by: Ed W Closes: https://lore.kernel.org/587f25e0-a80e-46a5-9f01-87cb40cfa377@wildgooses.com/ [1] Tested-by: Ed W # x86_64 Link: https://patch.msgid.link/20260225-separate-modinfo-from-elf-details-v1-1-387ced6baf4b@kernel.org Signed-off-by: Nathan Chancellor

mm: introduce CONFIG_ARCH_HAS_LAZY_MMU_MODE

2026-01-21T03:24:33+00:00

Architectures currently opt in for implementing lazy_mmu helpers by defining __HAVE_ARCH_ENTER_LAZY_MMU_MODE. In preparation for introducing a generic lazy_mmu layer that will require storage in task_struct, let's switch to a cleaner approach: instead of defining a macro, select a CONFIG option. This patch introduces CONFIG_ARCH_HAS_LAZY_MMU_MODE and has each arch select it when it implements lazy_mmu helpers. __HAVE_ARCH_ENTER_LAZY_MMU_MODE is removed and relies on the new CONFIG instead. On x86, lazy_mmu helpers are only implemented if PARAVIRT_XXL is selected. This creates some complications in arch/x86/boot/, because a few files manually undefine PARAVIRT* options. As a result does not define the lazy_mmu helpers, but this breaks the build as only defines them if !CONFIG_ARCH_HAS_LAZY_MMU_MODE. There does not seem to be a clean way out of this - let's just undefine that new CONFIG too. Link: https://lkml.kernel.org/r/20251215150323.2218608-7-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky Acked-by: David Hildenbrand Reviewed-by: Ritesh Harjani (IBM) Reviewed-by: Ryan Roberts Reviewed-by: Yeoreum Yun Acked-by: Andreas Larsson [sparc] Cc: Alexander Gordeev Cc: Anshuman Khandual Cc: Borislav Betkov Cc: Boris Ostrovsky Cc: Catalin Marinas Cc: Christophe Leroy Cc: David Hildenbrand (Red Hat) Cc: David S. Miller Cc: David Woodhouse Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jann Horn Cc: Juegren Gross Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Suren Baghdasaryan Cc: Thomas Gleinxer Cc: Venkat Rao Bagalkote Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton