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

x86/virt/tdx: Avoid indirect calls to TDX assembly functions

2025-06-27T10:11:38+00:00

commit 0b3bc018e86afdc0cbfef61328c63d5c08f8b370 upstream. Two 'static inline' TDX helper functions (sc_retry() and sc_retry_prerr()) take function pointer arguments which refer to assembly functions. Normally, the compiler inlines the TDX helper, realizes that the function pointer targets are completely static -- thus can be resolved at compile time -- and generates direct call instructions. But, other times (like when CONFIG_CC_OPTIMIZE_FOR_SIZE=y), the compiler declines to inline the helpers and will instead generate indirect call instructions. Indirect calls to assembly functions require special annotation (for various Control Flow Integrity mechanisms). But TDX assembly functions lack the special annotations and can only be called directly. Annotate both the helpers as '__always_inline' to prod the compiler into maintaining the direct calls. There is no guarantee here, but Peter has volunteered to report the compiler bug if this assumption ever breaks[1]. Fixes: 1e66a7e27539 ("x86/virt/tdx: Handle SEAMCALL no entropy error in common code") Fixes: df01f5ae07dd ("x86/virt/tdx: Add SEAMCALL error printing for module initialization") Signed-off-by: Kai Huang Signed-off-by: Dave Hansen Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/20250605145914.GW39944@noisy.programming.kicks-ass.net/ [1] Link: https://lore.kernel.org/all/20250606130737.30713-1-kai.huang%40intel.com Signed-off-by: Greg Kroah-Hartman

x86/sev: Ensure that RMP table fixups are reserved

2024-10-23T10:34:06+00:00

The BIOS reserves RMP table memory via e820 reservations. This can still lead to RMP page faults during kexec if the host tries to access memory within the same 2MB region. Commit 400fea4b9651 ("x86/sev: Add callback to apply RMP table fixups for kexec" adjusts the e820 reservations for the RMP table so that the entire 2MB range at the start/end of the RMP table is marked reserved. The e820 reservations are then passed to firmware via SNP_INIT where they get marked HV-Fixed. The RMP table fixups are done after the e820 ranges have been added to memblock, allowing the fixup ranges to still be allocated and used by the system. The problem is that this memory range is now marked reserved in the e820 tables and during SNP initialization these reserved ranges are marked as HV-Fixed. This means that the pages cannot be used by an SNP guest, only by the hypervisor. However, the memory management subsystem does not make this distinction and can allocate one of those pages to an SNP guest. This will ultimately result in RMPUPDATE failures associated with the guest, causing it to fail to start or terminate when accessing the HV-Fixed page. The issue is captured below with memblock=debug: [ 0.000000] SEV-SNP: *** DEBUG: snp_probe_rmptable_info:352 - rmp_base=0x280d4800000, rmp_end=0x28357efffff ... [ 0.000000] BIOS-provided physical RAM map: ... [ 0.000000] BIOS-e820: [mem 0x00000280d4800000-0x0000028357efffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000028357f00000-0x0000028357ffffff] usable ... ... [ 0.183593] memblock add: [0x0000028357f00000-0x0000028357ffffff] e820__memblock_setup+0x74/0xb0 ... [ 0.203179] MEMBLOCK configuration: [ 0.207057] memory size = 0x0000027d0d194000 reserved size = 0x0000000009ed2c00 [ 0.215299] memory.cnt = 0xb ... [ 0.311192] memory[0x9] [0x0000028357f00000-0x0000028357ffffff], 0x0000000000100000 bytes flags: 0x0 ... ... [ 0.419110] SEV-SNP: Reserving start/end of RMP table on a 2MB boundary [0x0000028357e00000] [ 0.428514] e820: update [mem 0x28357e00000-0x28357ffffff] usable ==> reserved [ 0.428517] e820: update [mem 0x28357e00000-0x28357ffffff] usable ==> reserved [ 0.428520] e820: update [mem 0x28357e00000-0x28357ffffff] usable ==> reserved ... ... [ 5.604051] MEMBLOCK configuration: [ 5.607922] memory size = 0x0000027d0d194000 reserved size = 0x0000000011faae02 [ 5.616163] memory.cnt = 0xe ... [ 5.754525] memory[0xc] [0x0000028357f00000-0x0000028357ffffff], 0x0000000000100000 bytes on node 0 flags: 0x0 ... ... [ 10.080295] Early memory node ranges[ 10.168065] ... node 0: [mem 0x0000028357f00000-0x0000028357ffffff] ... ... [ 8149.348948] SEV-SNP: RMPUPDATE failed for PFN 28357f7c, pg_level: 1, ret: 2 As shown above, the memblock allocations show 1MB after the end of the RMP as available for allocation, which is what the RMP table fixups have reserved. This memory range subsequently gets allocated as SNP guest memory, resulting in an RMPUPDATE failure. This can potentially be fixed by not reserving the memory range in the e820 table, but that causes kexec failures when using the KEXEC_FILE_LOAD syscall. The solution is to use memblock_reserve() to mark the memory reserved for the system, ensuring that it cannot be allocated to an SNP guest. Since HV-Fixed memory is still readable/writable by the host, this only ends up being a problem if the memory in this range requires a page state change, which generally will only happen when allocating memory in this range to be used for running SNP guests, which is now possible with the SNP hypervisor support in kernel 6.11. Backporter note: Fixes tag points to a 6.9 change but as the last paragraph above explains, this whole thing can happen after 6.11 received SNP HV support, therefore backporting to 6.9 is not really necessary. [ bp: Massage commit message. ] Fixes: 400fea4b9651 ("x86/sev: Add callback to apply RMP table fixups for kexec") Suggested-by: Thomas Lendacky Signed-off-by: Ashish Kalra Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Tom Lendacky Cc: # 6.11, see Backporter note above. Link: https://lore.kernel.org/r/20240815221630.131133-1-Ashish.Kalra@amd.com

Merge tag 'x86_sev_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2024-07-16T18:12:25+00:00

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()

x86/sev: Do RMP memory coverage check after max_pfn has been set

2024-07-11T10:03:23+00:00

The RMP table is probed early in the boot process before max_pfn has been set, so the logic to check if the RMP covers all of system memory is not valid. Move the RMP memory coverage check from snp_probe_rmptable_info() into snp_rmptable_init(), which is well after max_pfn has been set. Also, fix the calculation to use PFN_UP instead of PHYS_PFN, in order to compute the required RMP size properly. Fixes: 216d106c7ff7 ("x86/sev: Add SEV-SNP host initialization support") Signed-off-by: Tom Lendacky Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/bec4364c7e34358cc576f01bb197a7796a109169.1718984524.git.thomas.lendacky@amd.com

x86/virt/tdx: Switch to new Intel CPU model defines

2024-05-28T17:59:02+00:00

New CPU #defines encode vendor and family as well as model. Signed-off-by: Tony Luck Signed-off-by: Dave Hansen Link: https://lore.kernel.org/all/20240520224620.9480-31-tony.luck%40intel.com

Merge tag 'x86-cleanups-2024-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2024-05-14T01:21:24+00:00

Pull x86 cleanups from Ingo Molnar: - Fix function prototypes to address clang function type cast warnings in the math-emu code - Reorder definitions in - Remove unused code - Fix typos - Simplify #include sections * tag 'x86-cleanups-2024-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/pci/ce4100: Remove unused 'struct sim_reg_op' x86/msr: Move ARCH_CAP_XAPIC_DISABLE bit definition to its rightful place x86/math-emu: Fix function cast warnings x86/extable: Remove unused fixup type EX_TYPE_COPY x86/rtc: Remove unused intel-mid.h x86/32: Remove unused IA32_STACK_TOP and two externs x86/head: Simplify relative include path to xen-head.S x86/fred: Fix typo in Kconfig description x86/syscall/compat: Remove ia32_unistd.h x86/syscall/compat: Remove unused macro __SYSCALL_ia32_NR x86/virt/tdx: Remove duplicate include x86/xen: Remove duplicate #include

x86/sev: Add callback to apply RMP table fixups for kexec

2024-04-29T09:21:09+00:00

Handle cases where the RMP table placement in the BIOS is not 2M aligned and the kexec-ed kernel could try to allocate from within that chunk which then causes a fatal RMP fault. The kexec failure is illustrated below: SEV-SNP: RMP table physical range [0x0000007ffe800000 - 0x000000807f0fffff] BIOS-provided physical RAM map: BIOS-e820: [mem 0x0000000000000000-0x000000000008efff] usable BIOS-e820: [mem 0x000000000008f000-0x000000000008ffff] ACPI NVS ... BIOS-e820: [mem 0x0000004080000000-0x0000007ffe7fffff] usable BIOS-e820: [mem 0x0000007ffe800000-0x000000807f0fffff] reserved BIOS-e820: [mem 0x000000807f100000-0x000000807f1fefff] usable As seen here in the e820 memory map, the end range of the RMP table is not aligned to 2MB and not reserved but it is usable as RAM. Subsequently, kexec -s (KEXEC_FILE_LOAD syscall) loads it's purgatory code and boot_param, command line and other setup data into this RAM region as seen in the kexec logs below, which leads to fatal RMP fault during kexec boot. Loaded purgatory at 0x807f1fa000 Loaded boot_param, command line and misc at 0x807f1f8000 bufsz=0x1350 memsz=0x2000 Loaded 64bit kernel at 0x7ffae00000 bufsz=0xd06200 memsz=0x3894000 Loaded initrd at 0x7ff6c89000 bufsz=0x4176014 memsz=0x4176014 E820 memmap: 0000000000000000-000000000008efff (1) 000000000008f000-000000000008ffff (4) 0000000000090000-000000000009ffff (1) ... 0000004080000000-0000007ffe7fffff (1) 0000007ffe800000-000000807f0fffff (2) 000000807f100000-000000807f1fefff (1) 000000807f1ff000-000000807fffffff (2) nr_segments = 4 segment[0]: buf=0x00000000e626d1a2 bufsz=0x4000 mem=0x807f1fa000 memsz=0x5000 segment[1]: buf=0x0000000029c67bd6 bufsz=0x1350 mem=0x807f1f8000 memsz=0x2000 segment[2]: buf=0x0000000045c60183 bufsz=0xd06200 mem=0x7ffae00000 memsz=0x3894000 segment[3]: buf=0x000000006e54f08d bufsz=0x4176014 mem=0x7ff6c89000 memsz=0x4177000 kexec_file_load: type:0, start:0x807f1fa150 head:0x1184d0002 flags:0x0 Check if RMP table start and end physical range in the e820 tables are not aligned to 2MB and in that case map this range to reserved in all the three e820 tables. [ bp: Massage. ] Fixes: c3b86e61b756 ("x86/cpufeatures: Enable/unmask SEV-SNP CPU feature") Signed-off-by: Ashish Kalra Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/df6e995ff88565262c2c7c69964883ff8aa6fc30.1714090302.git.ashish.kalra@amd.com

x86/CPU/AMD: Track SNP host status with cc_platform_*()

2024-04-04T08:40:30+00:00

The host SNP worthiness can determined later, after alternatives have been patched, in snp_rmptable_init() depending on cmdline options like iommu=pt which is incompatible with SNP, for example. Which means that one cannot use X86_FEATURE_SEV_SNP and will need to have a special flag for that control. Use that newly added CC_ATTR_HOST_SEV_SNP in the appropriate places. Move kdump_sev_callback() to its rightful place, while at it. Fixes: 216d106c7ff7 ("x86/sev: Add SEV-SNP host initialization support") Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Tom Lendacky Tested-by: Srikanth Aithal Link: https://lore.kernel.org/r/20240327154317.29909-6-bp@alien8.de

x86/build: Use obj-y to descend into arch/x86/virt/

2024-03-30T09:41:49+00:00

Commit c33621b4c5ad ("x86/virt/tdx: Wire up basic SEAMCALL functions") introduced a new instance of core-y instead of the standardized obj-y syntax. X86 Makefiles descend into subdirectories of arch/x86/virt inconsistently; into arch/x86/virt/ via core-y defined in arch/x86/Makefile, but into arch/x86/virt/svm/ via obj-y defined in arch/x86/Kbuild. This is problematic when you build a single object in parallel because multiple threads attempt to build the same file. $ make -j$(nproc) arch/x86/virt/vmx/tdx/seamcall.o [ snip ] AS arch/x86/virt/vmx/tdx/seamcall.o AS arch/x86/virt/vmx/tdx/seamcall.o fixdep: error opening file: arch/x86/virt/vmx/tdx/.seamcall.o.d: No such file or directory make[4]: *** [scripts/Makefile.build:362: arch/x86/virt/vmx/tdx/seamcall.o] Error 2 Use the obj-y syntax, as it works correctly. Signed-off-by: Masahiro Yamada Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20240330060554.18524-1-masahiroy@kernel.org

x86/virt/tdx: Remove duplicate include

2024-03-22T08:35:43+00:00

./arch/x86/virt/vmx/tdx/tdx.c: linux/acpi.h is included more than once. Reported-by: Abaci Robot Signed-off-by: Jiapeng Chong Signed-off-by: Ingo Molnar Reviewed-by: Kai Huang Link: https://lore.kernel.org/r/20240322061741.9869-1-jiapeng.chong@linux.alibaba.com Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=8609