kernel/linux.git/arch/x86/platform, branch v6.1.168

x86/efi: efi_unmap_boot_services: fix calculation of ranges_to_free size

2026-04-11T12:16:11+00:00

[ Upstream commit 217c0a5c177a3d4f7c8497950cbf5c36756e8bbb ] ranges_to_free array should have enough room to store the entire EFI memmap plus an extra element for NULL entry. The calculation of this array size wrongly adds 1 to the overall size instead of adding 1 to the number of elements. Add parentheses to properly size the array. Reported-by: Guenter Roeck Fixes: a4b0bf6a40f3 ("x86/efi: defer freeing of boot services memory") Signed-off-by: Mike Rapoport (Microsoft) Signed-off-by: Ard Biesheuvel Signed-off-by: Sasha Levin

x86/efi: defer freeing of boot services memory

2026-03-25T10:02:58+00:00

commit a4b0bf6a40f3c107c67a24fbc614510ef5719980 upstream. efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE and EFI_BOOT_SERVICES_DATA using memblock_free_late(). There are two issue with that: memblock_free_late() should be used for memory allocated with memblock_alloc() while the memory reserved with memblock_reserve() should be freed with free_reserved_area(). More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y efi_free_boot_services() is called before deferred initialization of the memory map is complete. Benjamin Herrenschmidt reports that this causes a leak of ~140MB of RAM on EC2 t3a.nano instances which only have 512MB or RAM. If the freed memory resides in the areas that memory map for them is still uninitialized, they won't be actually freed because memblock_free_late() calls memblock_free_pages() and the latter skips uninitialized pages. Using free_reserved_area() at this point is also problematic because __free_page() accesses the buddy of the freed page and that again might end up in uninitialized part of the memory map. Delaying the entire efi_free_boot_services() could be problematic because in addition to freeing boot services memory it updates efi.memmap without any synchronization and that's undesirable late in boot when there is concurrency. More robust approach is to only defer freeing of the EFI boot services memory. Split efi_free_boot_services() in two. First efi_unmap_boot_services() collects ranges that should be freed into an array then efi_free_boot_services() later frees them after deferred init is complete. Link: https://lore.kernel.org/all/ec2aaef14783869b3be6e3c253b2dcbf67dbc12a.camel@kernel.crashing.org Fixes: 916f676f8dc0 ("x86, efi: Retain boot service code until after switching to virtual mode") Cc: Signed-off-by: Mike Rapoport (Microsoft) Reviewed-by: Benjamin Herrenschmidt Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman

x86/xen/pvh: Enable PAE mode for 32-bit guest only when CONFIG_X86_PAE is set

2026-03-04T12:20:14+00:00

[ Upstream commit db9aded979b491a24871e1621cd4e8822dbca859 ] The PVH entry is available for 32-bit KVM guests, and 32-bit KVM guests do not depend on CONFIG_X86_PAE. However, mk_early_pgtbl_32() builds different pagetables depending on whether CONFIG_X86_PAE is set. Therefore, enabling PAE mode for 32-bit KVM guests without CONFIG_X86_PAE being set would result in a boot failure during CR3 loading. Signed-off-by: Hou Wenlong Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross Message-ID: Signed-off-by: Sasha Levin

x86/pvh: Call C code via the kernel virtual mapping

2025-04-25T08:44:01+00:00

commit e8fbc0d9cab6c1ee6403f42c0991b0c1d5dbc092 upstream. Calling C code via a different mapping than it was linked at is problematic, because the compiler assumes that RIP-relative and absolute symbol references are interchangeable. GCC in particular may use RIP-relative per-CPU variable references even when not using -fpic. So call xen_prepare_pvh() via its kernel virtual mapping on x86_64, so that those RIP-relative references produce the correct values. This matches the pre-existing behavior for i386, which also invokes xen_prepare_pvh() via the kernel virtual mapping before invoking startup_32 with paging disabled again. Fixes: 7243b93345f7 ("xen/pvh: Bootstrap PVH guest") Tested-by: Jason Andryuk Reviewed-by: Jason Andryuk Signed-off-by: Ard Biesheuvel Message-ID: <20241009160438.3884381-8-ardb+git@google.com> Signed-off-by: Juergen Gross [ Stable context update ] Signed-off-by: Jason Andryuk Signed-off-by: Greg Kroah-Hartman

x86/platform/iosf_mbi: Convert PCIBIOS_* return codes to errnos

2024-08-03T06:48:54+00:00

[ Upstream commit 7821fa101eab529521aa4b724bf708149d70820c ] iosf_mbi_pci_{read,write}_mdr() use pci_{read,write}_config_dword() that return PCIBIOS_* codes but functions also return -ENODEV which are not compatible error codes. As neither of the functions are related to PCI read/write functions, they should return normal errnos. Convert PCIBIOS_* returns code using pcibios_err_to_errno() into normal errno before returning it. Fixes: 46184415368a ("arch: x86: New MailBox support driver for Intel SOC's") Signed-off-by: Ilpo Järvinen Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20240527125538.13620-4-ilpo.jarvinen@linux.intel.com Signed-off-by: Sasha Levin

efi/x86: Free EFI memory map only when installing a new one.

2024-07-05T07:32:00+00:00

commit 75dde792d6f6c2d0af50278bd374bf0c512fe196 upstream. The logic in __efi_memmap_init() is shared between two different execution flows: - mapping the EFI memory map early or late into the kernel VA space, so that its entries can be accessed; - the x86 specific cloning of the EFI memory map in order to insert new entries that are created as a result of making a memory reservation via a call to efi_mem_reserve(). In the former case, the underlying memory containing the kernel's view of the EFI memory map (which may be heavily modified by the kernel itself on x86) is not modified at all, and the only thing that changes is the virtual mapping of this memory, which is different between early and late boot. In the latter case, an entirely new allocation is created that carries a new, updated version of the kernel's view of the EFI memory map. When installing this new version, the old version will no longer be referenced, and if the memory was allocated by the kernel, it will leak unless it gets freed. The logic that implements this freeing currently lives on the code path that is shared between these two use cases, but it should only apply to the latter. So move it to the correct spot. While at it, drop the dummy definition for non-x86 architectures, as that is no longer needed. Cc: Fixes: f0ef6523475f ("efi: Fix efi_memmap_alloc() leaks") Tested-by: Ashish Kalra Link: https://lore.kernel.org/all/36ad5079-4326-45ed-85f6-928ff76483d3@amd.com Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman

efi: xen: Set EFI_PARAVIRT for Xen dom0 boot on all architectures

2024-07-05T07:32:00+00:00

commit d85e3e34940788578eeffd94e8b7e1d28e7278e9 upstream. Currently, the EFI_PARAVIRT flag is only used by Xen dom0 boot on x86, even though other architectures also support pseudo-EFI boot, where the core kernel is invoked directly and provided with a set of data tables that resemble the ones constructed by the EFI stub, which never actually runs in that case. Let's fix this inconsistency, and always set this flag when booting dom0 via the EFI boot path. Note that Xen on x86 does not provide the EFI memory map in this case, whereas other architectures do, so move the associated EFI_PARAVIRT check into the x86 platform code. Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman

efi: memmap: Move manipulation routines into x86 arch tree

2024-07-05T07:32:00+00:00

commit fdc6d38d64a20c542b1867ebeb8dd03b98829336 upstream. The EFI memory map is a description of the memory layout as provided by the firmware, and only x86 manipulates it in various different ways for its own memory bookkeeping. So let's move the memmap routines that are only used by x86 into the x86 arch tree. Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman

x86/efi: Make efi_set_virtual_address_map IBT safe

2023-07-19T14:21:45+00:00

[ Upstream commit 0303c9729afc4094ef53e552b7b8cff7436028d6 ] Niklāvs reported a boot regression on an Alderlake machine and bisected it to commit 9df9d2f0471b ("init: Invoke arch_cpu_finalize_init() earlier"). By moving the invocation of arch_cpu_finalize_init() further down he identified that efi_enter_virtual_mode() is the function which causes the boot hang. The main difference of the earlier invocation is that the boot CPU is already fully initialized and mitigations and alternatives are applied. But the only really interesting change turned out to be IBT, which is now enabled before efi_enter_virtual_mode(). "ibt=off" on the kernel command line cured the problem. Inspection of the involved calls in efi_enter_virtual_mode() unearthed that efi_set_virtual_address_map() is the only place in the kernel which invokes an EFI call without the IBT safe wrapper. This went obviously unnoticed so far as IBT was enabled later. Use arch_efi_call_virt() instead of efi_call() to cure that. Fixes: fe379fa4d199 ("x86/ibt: Disable IBT around firmware") Fixes: 9df9d2f0471b ("init: Invoke arch_cpu_finalize_init() earlier") Reported-by: Niklāvs Koļesņikovs Signed-off-by: Thomas Gleixner Reviewed-by: Ard Biesheuvel Link: https://bugzilla.kernel.org/show_bug.cgi?id=217602 Link: https://lore.kernel.org/r/87jzvm12q0.ffs@tglx Signed-off-by: Sasha Levin

Merge tag 'efi-next-for-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

2022-10-09T15:56:54+00:00

Pull EFI updates from Ard Biesheuvel: "A bit more going on than usual in the EFI subsystem. The main driver for this has been the introduction of the LoonArch architecture last cycle, which inspired some cleanup and refactoring of the EFI code. Another driver for EFI changes this cycle and in the future is confidential compute. The LoongArch architecture does not use either struct bootparams or DT natively [yet], and so passing information between the EFI stub and the core kernel using either of those is undesirable. And in general, overloading DT has been a source of issues on arm64, so using DT for this on new architectures is a to avoid for the time being (even if we might converge on something DT based for non-x86 architectures in the future). For this reason, in addition to the patch that enables EFI boot for LoongArch, there are a number of refactoring patches applied on top of which separate the DT bits from the generic EFI stub bits. These changes are on a separate topich branch that has been shared with the LoongArch maintainers, who will include it in their pull request as well. This is not ideal, but the best way to manage the conflicts without stalling LoongArch for another cycle. Another development inspired by LoongArch is the newly added support for EFI based decompressors. Instead of adding yet another arch-specific incarnation of this pattern for LoongArch, we are introducing an EFI app based on the existing EFI libstub infrastructure that encapulates the decompression code we use on other architectures, but in a way that is fully generic. This has been developed and tested in collaboration with distro and systemd folks, who are eager to start using this for systemd-boot and also for arm64 secure boot on Fedora. Note that the EFI zimage files this introduces can also be decompressed by non-EFI bootloaders if needed, as the image header describes the location of the payload inside the image, and the type of compression that was used. (Note that Fedora's arm64 GRUB is buggy [0] so you'll need a recent version or switch to systemd-boot in order to use this.) Finally, we are adding TPM measurement of the kernel command line provided by EFI. There is an oversight in the TCG spec which results in a blind spot for command line arguments passed to loaded images, which means that either the loader or the stub needs to take the measurement. Given the combinatorial explosion I am anticipating when it comes to firmware/bootloader stacks and firmware based attestation protocols (SEV-SNP, TDX, DICE, DRTM), it is good to set a baseline now when it comes to EFI measured boot, which is that the kernel measures the initrd and command line. Intermediate loaders can measure additional assets if needed, but with the baseline in place, we can deploy measured boot in a meaningful way even if you boot into Linux straight from the EFI firmware. Summary: - implement EFI boot support for LoongArch - implement generic EFI compressed boot support for arm64, RISC-V and LoongArch, none of which implement a decompressor today - measure the kernel command line into the TPM if measured boot is in effect - refactor the EFI stub code in order to isolate DT dependencies for architectures other than x86 - avoid calling SetVirtualAddressMap() on arm64 if the configured size of the VA space guarantees that doing so is unnecessary - move some ARM specific code out of the generic EFI source files - unmap kernel code from the x86 mixed mode 1:1 page tables" * tag 'efi-next-for-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: (24 commits) efi/arm64: libstub: avoid SetVirtualAddressMap() when possible efi: zboot: create MemoryMapped() device path for the parent if needed efi: libstub: fix up the last remaining open coded boot service call efi/arm: libstub: move ARM specific code out of generic routines efi/libstub: measure EFI LoadOptions efi/libstub: refactor the initrd measuring functions efi/loongarch: libstub: remove dependency on flattened DT efi: libstub: install boot-time memory map as config table efi: libstub: remove DT dependency from generic stub efi: libstub: unify initrd loading between architectures efi: libstub: remove pointless goto kludge efi: libstub: simplify efi_get_memory_map() and struct efi_boot_memmap efi: libstub: avoid efi_get_memory_map() for allocating the virt map efi: libstub: drop pointless get_memory_map() call efi: libstub: fix type confusion for load_options_size arm64: efi: enable generic EFI compressed boot loongarch: efi: enable generic EFI compressed boot riscv: efi: enable generic EFI compressed boot efi/libstub: implement generic EFI zboot efi/libstub: move efi_system_table global var into separate object ...