kernel/linux.git/arch/x86/include/asm/shared, branch v6.6.131

x86/tdx: Dynamically disable SEPT violations from causing #VEs

2024-12-09T09:32:20+00:00

[ Upstream commit f65aa0ad79fca4ace921da0701644f020129043d ] Memory access #VEs are hard for Linux to handle in contexts like the entry code or NMIs. But other OSes need them for functionality. There's a static (pre-guest-boot) way for a VMM to choose one or the other. But VMMs don't always know which OS they are booting, so they choose to deliver those #VEs so the "other" OSes will work. That, unfortunately has left us in the lurch and exposed to these hard-to-handle #VEs. The TDX module has introduced a new feature. Even if the static configuration is set to "send nasty #VEs", the kernel can dynamically request that they be disabled. Once they are disabled, access to private memory that is not in the Mapped state in the Secure-EPT (SEPT) will result in an exit to the VMM rather than injecting a #VE. Check if the feature is available and disable SEPT #VE if possible. If the TD is allowed to disable/enable SEPT #VEs, the ATTR_SEPT_VE_DISABLE attribute is no longer reliable. It reflects the initial state of the control for the TD, but it will not be updated if someone (e.g. bootloader) changes it before the kernel starts. Kernel must check TDCS_TD_CTLS bit to determine if SEPT #VEs are enabled or disabled. [ dhansen: remove 'return' at end of function ] Fixes: 373e715e31bf ("x86/tdx: Panic on bad configs that #VE on "private" memory access") Signed-off-by: Kirill A. Shutemov Signed-off-by: Dave Hansen Acked-by: Kai Huang Link: https://lore.kernel.org/all/20241104103803.195705-4-kirill.shutemov%40linux.intel.com Signed-off-by: Sasha Levin

x86/tdx: Introduce wrappers to read and write TD metadata

2024-12-09T09:32:19+00:00

[ Upstream commit 5081e8fadb809253c911b349b01d87c5b4e3fec5 ] The TDG_VM_WR TDCALL is used to ask the TDX module to change some TD-specific VM configuration. There is currently only one user in the kernel of this TDCALL leaf. More will be added shortly. Refactor to make way for more users of TDG_VM_WR who will need to modify other TD configuration values. Add a wrapper for the TDG_VM_RD TDCALL that requests TD-specific metadata from the TDX module. There are currently no users for TDG_VM_RD. Mark it as __maybe_unused until the first user appears. This is preparation for enumeration and enabling optional TD features. Signed-off-by: Kirill A. Shutemov Signed-off-by: Dave Hansen Reviewed-by: Kai Huang Reviewed-by: Kuppuswamy Sathyanarayanan Link: https://lore.kernel.org/all/20241104103803.195705-2-kirill.shutemov%40linux.intel.com Stable-dep-of: f65aa0ad79fc ("x86/tdx: Dynamically disable SEPT violations from causing #VEs") Signed-off-by: Sasha Levin

x86/tdx: Pass TDCALL/SEAMCALL input/output registers via a structure

2024-12-09T09:32:19+00:00

[ Upstream commit 57a420bb8186d1d0178b857e5dd5026093641654 ] Currently, the TDX_MODULE_CALL asm macro, which handles both TDCALL and SEAMCALL, takes one parameter for each input register and an optional 'struct tdx_module_output' (a collection of output registers) as output. This is different from the TDX_HYPERCALL macro which uses a single 'struct tdx_hypercall_args' to carry all input/output registers. The newer TDX versions introduce more TDCALLs/SEAMCALLs which use more input/output registers. Also, the TDH.VP.ENTER (which isn't covered by the current TDX_MODULE_CALL macro) basically can use all registers that the TDX_HYPERCALL does. The current TDX_MODULE_CALL macro isn't extendible to cover those cases. Similar to the TDX_HYPERCALL macro, simplify the TDX_MODULE_CALL macro to use a single structure 'struct tdx_module_args' to carry all the input/output registers. Currently, R10/R11 are only used as output register but not as input by any TDCALL/SEAMCALL. Change to also use R10/R11 as input register to make input/output registers symmetric. Currently, the TDX_MODULE_CALL macro depends on the caller to pass a non-NULL 'struct tdx_module_output' to get additional output registers. Similar to the TDX_HYPERCALL macro, change the TDX_MODULE_CALL macro to take a new 'ret' macro argument to indicate whether to save the output registers to the 'struct tdx_module_args'. Also introduce a new __tdcall_ret() for that purpose, similar to the __tdx_hypercall_ret(). Note the tdcall(), which is a wrapper of __tdcall(), is called by three callers: tdx_parse_tdinfo(), tdx_get_ve_info() and tdx_early_init(). The former two need the additional output but the last one doesn't. For simplicity, make tdcall() always call __tdcall_ret() to avoid another "_ret()" wrapper. The last caller tdx_early_init() isn't performance critical anyway. Suggested-by: Peter Zijlstra Signed-off-by: Kai Huang Signed-off-by: Dave Hansen Reviewed-by: Kirill A. Shutemov Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/all/483616c1762d85eb3a3c3035a7de061cfacf2f14.1692096753.git.kai.huang%40intel.com Stable-dep-of: f65aa0ad79fc ("x86/tdx: Dynamically disable SEPT violations from causing #VEs") Signed-off-by: Sasha Levin

x86/tdx: Rename __tdx_module_call() to __tdcall()

2024-12-09T09:32:19+00:00

[ Upstream commit 5efb96289e581c187af1bc288ce5d26ed6181749 ] __tdx_module_call() is only used by the TDX guest to issue TDCALL to the TDX module. Rename it to __tdcall() to match its behaviour, e.g., it cannot be used to make host-side SEAMCALL. Also rename tdx_module_call() which is a wrapper of __tdx_module_call() to tdcall(). No functional change intended. Signed-off-by: Kai Huang Signed-off-by: Dave Hansen Reviewed-by: Kirill A. Shutemov Reviewed-by: Kuppuswamy Sathyanarayanan Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/all/785d20d99fbcd0db8262c94da6423375422d8c75.1692096753.git.kai.huang%40intel.com Stable-dep-of: f65aa0ad79fc ("x86/tdx: Dynamically disable SEPT violations from causing #VEs") Signed-off-by: Sasha Levin

x86/tdx: Make macros of TDCALLs consistent with the spec

2024-12-09T09:32:19+00:00

[ Upstream commit f0024dbfc48d8814d915eb5bd5253496b9b8a6df ] The TDX spec names all TDCALLs with prefix "TDG". Currently, the kernel doesn't follow such convention for the macros of those TDCALLs but uses prefix "TDX_" for all of them. Although it's arguable whether the TDX spec names those TDCALLs properly, it's better for the kernel to follow the spec when naming those macros. Change all macros of TDCALLs to make them consistent with the spec. As a bonus, they get distinguished easily from the host-side SEAMCALLs, which all have prefix "TDH". No functional change intended. Signed-off-by: Kai Huang Signed-off-by: Dave Hansen Reviewed-by: Kirill A. Shutemov Reviewed-by: Kuppuswamy Sathyanarayanan Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/all/516dccd0bd8fb9a0b6af30d25bb2d971aa03d598.1692096753.git.kai.huang%40intel.com Stable-dep-of: f65aa0ad79fc ("x86/tdx: Dynamically disable SEPT violations from causing #VEs") Signed-off-by: Sasha Levin

Merge tag 'x86_tdx_for_6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2023-06-26T23:32:47+00:00

Pull x86 tdx updates from Dave Hansen: - Fix a race window where load_unaligned_zeropad() could cause a fatal shutdown during TDX private<=>shared conversion The race has never been observed in practice but might allow load_unaligned_zeropad() to catch a TDX page in the middle of its conversion process which would lead to a fatal and unrecoverable guest shutdown. - Annotate sites where VM "exit reasons" are reused as hypercall numbers. * tag 'x86_tdx_for_6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm: Fix enc_status_change_finish_noop() x86/tdx: Fix race between set_memory_encrypted() and load_unaligned_zeropad() x86/mm: Allow guest.enc_status_change_prepare() to fail x86/tdx: Wrap exit reason with hcall_func()

x86/tdx: Add unaccepted memory support

2023-06-06T16:25:57+00:00

Hookup TDX-specific code to accept memory. Accepting the memory is done with ACCEPT_PAGE module call on every page in the range. MAP_GPA hypercall is not required as the unaccepted memory is considered private already. Extract the part of tdx_enc_status_changed() that does memory acceptance in a new helper. Move the helper tdx-shared.c. It is going to be used by both main kernel and decompressor. [ bp: Fix the INTEL_TDX_GUEST=y, KVM_GUEST=n build. ] Signed-off-by: Kirill A. Shutemov Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230606142637.5171-10-kirill.shutemov@linux.intel.com

x86/tdx: Make _tdx_hypercall() and __tdx_module_call() available in boot stub

2023-06-06T15:31:23+00:00

Memory acceptance requires a hypercall and one or multiple module calls. Make helpers for the calls available in boot stub. It has to accept memory where kernel image and initrd are placed. Signed-off-by: Kirill A. Shutemov Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Dave Hansen Link: https://lore.kernel.org/r/20230606142637.5171-8-kirill.shutemov@linux.intel.com

x86/tdx: Wrap exit reason with hcall_func()

2023-05-23T14:01:45+00:00

TDX reuses VMEXIT "reasons" in its guest->host hypercall ABI. This is confusing because there might not be a VMEXIT involved at *all*. These instances are supposed to document situation and reduce confusion by wrapping VMEXIT reasons with hcall_func(). The decompression code does not follow this convention. Unify the TDX decompression code with the other TDX use of VMEXIT reasons. No functional changes. Signed-off-by: Nikolay Borisov Signed-off-by: Dave Hansen Acked-by: Kirill A. Shutemov Link: https://lore.kernel.org/all/20230505120332.1429957-1-nik.borisov%40suse.com

x86/tdx: Drop flags from __tdx_hypercall()

2023-03-22T18:36:05+00:00

After TDX_HCALL_ISSUE_STI got dropped, the only flag left is TDX_HCALL_HAS_OUTPUT. The flag indicates if the caller wants to see tdx_hypercall_args updated based on the hypercall output. Drop the flags and provide __tdx_hypercall_ret() that matches TDX_HCALL_HAS_OUTPUT semantics. Suggested-by: Peter Zijlstra Signed-off-by: Kirill A. Shutemov Signed-off-by: Dave Hansen Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/all/20230321003511.9469-1-kirill.shutemov%40linux.intel.com