kernel/linux.git/arch/x86/platform, branch v6.12.80

x86/efi: efi_unmap_boot_services: fix calculation of ranges_to_free size

2026-04-02T11:09:38+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

2026-03-13T16:20:33+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

2026-03-04T12:20:53+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

2024-12-05T13:01:12+00:00

[ Upstream commit e8fbc0d9cab6c1ee6403f42c0991b0c1d5dbc092 ] 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 Signed-off-by: Sasha Levin

Merge tag 'for-linus-6.12-rc1a-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2024-09-27T16:55:30+00:00

Pull more xen updates from Juergen Gross: "A second round of Xen related changes and features: - a small fix of the xen-pciback driver for a warning issued by sparse - support PCI passthrough when using a PVH dom0 - enable loading the kernel in PVH mode at arbitrary addresses, avoiding conflicts with the memory map when running as a Xen dom0 using the host memory layout" * tag 'for-linus-6.12-rc1a-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: x86/pvh: Add 64bit relocation page tables x86/kernel: Move page table macros to header x86/pvh: Set phys_base when calling xen_prepare_pvh() x86/pvh: Make PVH entrypoint PIC for x86-64 xen: sync elfnote.h from xen tree xen/pciback: fix cast to restricted pci_ers_result_t and pci_power_t xen/privcmd: Add new syscall to get gsi from dev xen/pvh: Setup gsi for passthrough device xen/pci: Add a function to reset device for xen

x86/pvh: Add 64bit relocation page tables

2024-09-25T14:06:07+00:00

The PVH entry point is 32bit. For a 64bit kernel, the entry point must switch to 64bit mode, which requires a set of page tables. In the past, PVH used init_top_pgt. This works fine when the kernel is loaded at LOAD_PHYSICAL_ADDR, as the page tables are prebuilt for this address. If the kernel is loaded at a different address, they need to be adjusted. __startup_64() adjusts the prebuilt page tables for the physical load address, but it is 64bit code. The 32bit PVH entry code can't call it to adjust the page tables, so it can't readily be re-used. 64bit PVH entry needs page tables set up for identity map, the kernel high map and the direct map. pvh_start_xen() enters identity mapped. Inside xen_prepare_pvh(), it jumps through a pv_ops function pointer into the highmap. The direct map is used for __va() on the initramfs and other guest physical addresses. Add a dedicated set of prebuild page tables for PVH entry. They are adjusted in assembly before loading. Add XEN_ELFNOTE_PHYS32_RELOC to indicate support for relocation along with the kernel's loading constraints. The maximum load address, KERNEL_IMAGE_SIZE - 1, is determined by a single pvh_level2_ident_pgt page. It could be larger with more pages. Signed-off-by: Jason Andryuk Reviewed-by: Juergen Gross Message-ID: <20240823193630.2583107-6-jason.andryuk@amd.com> Signed-off-by: Juergen Gross

x86/pvh: Set phys_base when calling xen_prepare_pvh()

2024-09-25T12:15:11+00:00

phys_base needs to be set for __pa() to work in xen_pvh_init() when finding the hypercall page. Set it before calling into xen_prepare_pvh(), which calls xen_pvh_init(). Clear it afterward to avoid __startup_64() adding to it and creating an incorrect value. Signed-off-by: Jason Andryuk Reviewed-by: Juergen Gross Message-ID: <20240823193630.2583107-4-jason.andryuk@amd.com> Signed-off-by: Juergen Gross

x86/pvh: Make PVH entrypoint PIC for x86-64

2024-09-25T12:15:08+00:00

The PVH entrypoint is 32bit non-PIC code running the uncompressed vmlinux at its load address CONFIG_PHYSICAL_START - default 0x1000000 (16MB). The kernel is loaded at that physical address inside the VM by the VMM software (Xen/QEMU). When running a Xen PVH Dom0, the host reserved addresses are mapped 1-1 into the PVH container. There exist system firmwares (Coreboot/EDK2) with reserved memory at 16MB. This creates a conflict where the PVH kernel cannot be loaded at that address. Modify the PVH entrypoint to be position-indepedent to allow flexibility in load address. Only the 64bit entry path is converted. A 32bit kernel is not PIC, so calling into other parts of the kernel, like xen_prepare_pvh() and mk_pgtable_32(), don't work properly when relocated. This makes the code PIC, but the page tables need to be updated as well to handle running from the kernel high map. The UNWIND_HINT_END_OF_STACK is to silence: vmlinux.o: warning: objtool: pvh_start_xen+0x7f: unreachable instruction after the lret into 64bit code. Signed-off-by: Jason Andryuk Reviewed-by: Juergen Gross Message-ID: <20240823193630.2583107-3-jason.andryuk@amd.com> Signed-off-by: Juergen Gross

Merge tag 'platform-drivers-x86-v6.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86

2024-09-19T07:16:04+00:00

Pull x86 platform drivers updates from Hans de Goede: - asus-wmi: Add support for vivobook fan profiles - dell-laptop: Add knobs to change battery charge settings - lg-laptop: Add operation region support - intel-uncore-freq: Add support for efficiency latency control - intel/ifs: Add SBAF test support - intel/pmc: Ignore all LTRs during suspend - platform/surface: Support for arm64 based Surface devices - wmi: Pass event data directly to legacy notify handlers - x86/platform/geode: switch GPIO buttons and LEDs to software properties - bunch of small cleanups, fixes, hw-id additions, etc. * tag 'platform-drivers-x86-v6.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86: (65 commits) MAINTAINERS: adjust file entry in INTEL MID PLATFORM platform/x86: x86-android-tablets: Adjust Xiaomi Pad 2 bottom bezel touch buttons LED platform/mellanox: mlxbf-pmc: fix lockdep warning platform/x86/amd: pmf: Add quirk for TUF Gaming A14 platform/x86: touchscreen_dmi: add nanote-next quirk platform/x86: asus-wmi: don't fail if platform_profile already registered platform/x86: asus-wmi: add debug print in more key places platform/x86: intel_scu_wdt: Move intel_scu_wdt.h to x86 subfolder platform/x86: intel_scu_ipc: Move intel_scu_ipc.h out of arch/x86/include/asm MAINTAINERS: Add Intel MID section platform/x86: panasonic-laptop: Add support for programmable buttons platform/olpc: Remove redundant null pointer checks in olpc_ec_setup_debugfs() platform/x86: intel/pmc: Ignore all LTRs during suspend platform/x86: wmi: Call both legacy and WMI driver notify handlers platform/x86: wmi: Merge get_event_data() with wmi_get_notify_data() platform/x86: wmi: Remove wmi_get_event_data() platform/x86: wmi: Pass event data directly to legacy notify handlers platform/x86: thinkpad_acpi: Fix uninitialized symbol 's' warning platform/x86: x86-android-tablets: Fix spelling in the comments platform/x86: ideapad-laptop: Make the scope_guard() clear of its scope ...

xen, pvh: fix unbootable VMs by inlining memset() in xen_prepare_pvh()

2024-09-12T06:25:12+00:00

If this memset() is not inlined than PVH early boot code can call into KASAN-instrumented memset() which results in unbootable VMs. Signed-off-by: Alexey Dobriyan Acked-by: Juergen Gross Message-ID: <20240802154253.482658-3-adobriyan@gmail.com> Signed-off-by: Juergen Gross