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2025-06-26x86/bugs: Use IBPB for retbleed if used by SRSODavid Kaplan
If spec_rstack_overflow=ibpb then this mitigates retbleed as well. This is relevant for AMD Zen1 and Zen2 CPUs which are vulnerable to both bugs. Signed-off-by: David Kaplan <david.kaplan@amd.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de> Cc: H . Peter Anvin <hpa@zytor.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20250625155805.600376-3-david.kaplan@amd.com
2025-06-26x86/bugs: Add SRSO_MITIGATION_NOSMTDavid Kaplan
AMD Zen1 and Zen2 CPUs with SMT disabled are not vulnerable to SRSO. Instead of overloading the X86_FEATURE_SRSO_NO bit to indicate this, define a separate mitigation to make the code cleaner. Signed-off-by: David Kaplan <david.kaplan@amd.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de> Cc: H . Peter Anvin <hpa@zytor.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20250625155805.600376-2-david.kaplan@amd.com
2025-06-24x86/traps: Initialize DR7 by writing its architectural reset valueXin Li (Intel)
Initialize DR7 by writing its architectural reset value to always set bit 10, which is reserved to '1', when "clearing" DR7 so as not to trigger unanticipated behavior if said bit is ever unreserved, e.g. as a feature enabling flag with inverted polarity. Signed-off-by: Xin Li (Intel) <xin@zytor.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com> Reviewed-by: Sohil Mehta <sohil.mehta@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Sean Christopherson <seanjc@google.com> Tested-by: Sohil Mehta <sohil.mehta@intel.com> Cc:stable@vger.kernel.org Link: https://lore.kernel.org/all/20250620231504.2676902-3-xin%40zytor.com
2025-06-24x86/traps: Initialize DR6 by writing its architectural reset valueXin Li (Intel)
Initialize DR6 by writing its architectural reset value to avoid incorrectly zeroing DR6 to clear DR6.BLD at boot time, which leads to a false bus lock detected warning. The Intel SDM says: 1) Certain debug exceptions may clear bits 0-3 of DR6. 2) BLD induced #DB clears DR6.BLD and any other debug exception doesn't modify DR6.BLD. 3) RTM induced #DB clears DR6.RTM and any other debug exception sets DR6.RTM. To avoid confusion in identifying debug exceptions, debug handlers should set DR6.BLD and DR6.RTM, and clear other DR6 bits before returning. The DR6 architectural reset value 0xFFFF0FF0, already defined as macro DR6_RESERVED, satisfies these requirements, so just use it to reinitialize DR6 whenever needed. Since clear_all_debug_regs() no longer zeros all debug registers, rename it to initialize_debug_regs() to better reflect its current behavior. Since debug_read_clear_dr6() no longer clears DR6, rename it to debug_read_reset_dr6() to better reflect its current behavior. Fixes: ebb1064e7c2e9 ("x86/traps: Handle #DB for bus lock") Reported-by: Sohil Mehta <sohil.mehta@intel.com> Suggested-by: H. Peter Anvin (Intel) <hpa@zytor.com> Signed-off-by: Xin Li (Intel) <xin@zytor.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com> Reviewed-by: Sohil Mehta <sohil.mehta@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Sohil Mehta <sohil.mehta@intel.com> Link: https://lore.kernel.org/lkml/06e68373-a92b-472e-8fd9-ba548119770c@intel.com/ Cc:stable@vger.kernel.org Link: https://lore.kernel.org/all/20250620231504.2676902-2-xin%40zytor.com
2025-06-24x86/bugs: Allow ITS stuffing in eIBRS+retpoline mode alsoPawan Gupta
After a recent restructuring of the ITS mitigation, RSB stuffing can no longer be enabled in eIBRS+Retpoline mode. Before ITS, retbleed mitigation only allowed stuffing when eIBRS was not enabled. This was perfectly fine since eIBRS mitigates retbleed. However, RSB stuffing mitigation for ITS is still needed with eIBRS. The restructuring solely relies on retbleed to deploy stuffing, and does not allow it when eIBRS is enabled. This behavior is different from what was before the restructuring. Fix it by allowing stuffing in eIBRS+retpoline mode also. Fixes: 61ab72c2c6bf ("x86/bugs: Restructure ITS mitigation") Closes: https://lore.kernel.org/lkml/20250519235101.2vm6sc5txyoykb2r@desk/ Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/20250611-eibrs-fix-v4-7-5ff86cac6c61@linux.intel.com
2025-06-23x86/bugs: Remove its=stuff dependency on retbleedPawan Gupta
Allow ITS to enable stuffing independent of retbleed. The dependency is only on retpoline. It is a valid case for retbleed to be mitigated by eIBRS while ITS deploys stuffing at the same time. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/20250611-eibrs-fix-v4-6-5ff86cac6c61@linux.intel.com
2025-06-23x86/bugs: Introduce cdt_possible()Pawan Gupta
In preparation to allow ITS to also enable stuffing aka Call Depth Tracking (CDT) independently of retbleed, introduce a helper cdt_possible(). Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/20250611-eibrs-fix-v4-5-5ff86cac6c61@linux.intel.com
2025-06-23x86/bugs: Use switch/case in its_apply_mitigation()Pawan Gupta
Prepare to apply stuffing mitigation in its_apply_mitigation(). This is currently only done via retbleed mitigation. Also using switch/case makes it evident that mitigation mode like VMEXIT_ONLY doesn't need any special handling. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Nikolay Borisov <nik.borisov@suse.com> Link: https://lore.kernel.org/20250611-eibrs-fix-v4-4-5ff86cac6c61@linux.intel.com
2025-06-23x86/bugs: Avoid warning when overriding return thunkPawan Gupta
The purpose of the warning is to prevent an unexpected change to the return thunk mitigation. However, there are legitimate cases where the return thunk is intentionally set more than once. For example, ITS and SRSO both can set the return thunk after retbleed has set it. In both the cases retbleed is still mitigated. Replace the warning with an info about the active return thunk. Suggested-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/20250611-eibrs-fix-v4-3-5ff86cac6c61@linux.intel.com
2025-06-23x86/bugs: Simplify the retbleed=stuff checksPawan Gupta
Simplify the nested checks, remove redundant print and comment. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Nikolay Borisov <nik.borisov@suse.com> Acked-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/20250611-eibrs-fix-v4-2-5ff86cac6c61@linux.intel.com
2025-06-23x86/bugs: Avoid AUTO after the select step in the retbleed mitigationPawan Gupta
The retbleed select function leaves the mitigation to AUTO in some cases. Moreover, the update function can also set the mitigation to AUTO. This is inconsistent with other mitigations and requires explicit handling of AUTO at the end of update step. Make sure a mitigation gets selected in the select step, and do not change it to AUTO in the update step. When no mitigation can be selected leave it to NONE, which is what AUTO was getting changed to in the end. Suggested-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/20250611-eibrs-fix-v4-1-5ff86cac6c61@linux.intel.com
2025-06-21x86/CPU/AMD: Add CPUID faulting supportBorislav Petkov (AMD)
Add CPUID faulting support on AMD using the same user interface. Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/20250528213105.1149-1-bp@kernel.org
2025-06-20x86/efi: Move runtime service initialization to arch/x86Alexander Shishkin
The EFI call in start_kernel() is guarded by #ifdef CONFIG_X86. Move the thing to the arch_cpu_finalize_init() path on x86 and get rid of the #ifdef in start_kernel(). No functional change intended. Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Sohil Mehta <sohil.mehta@intel.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/all/20250620135325.3300848-5-kirill.shutemov%40linux.intel.com
2025-06-17x86/mm: Fix early boot use of INVPLGBRik van Riel
The INVLPGB instruction has limits on how many pages it can invalidate at once. That limit is enumerated in CPUID, read by the kernel, and stored in 'invpgb_count_max'. Ranged invalidation, like invlpgb_kernel_range_flush() break up their invalidations so that they do not exceed the limit. However, early boot code currently attempts to do ranged invalidation before populating 'invlpgb_count_max'. There is a for loop which is basically: for (...; addr < end; addr += invlpgb_count_max*PAGE_SIZE) If invlpgb_kernel_range_flush is called before the kernel has read the value of invlpgb_count_max from the hardware, the normally bounded loop can become an infinite loop if invlpgb_count_max is initialized to zero. Fix that issue by initializing invlpgb_count_max to 1. This way INVPLGB at early boot time will be a little bit slower than normal (with initialized invplgb_count_max), and not an instant hang at bootup time. Fixes: b7aa05cbdc52 ("x86/mm: Add INVLPGB support code") Signed-off-by: Rik van Riel <riel@surriel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lore.kernel.org/all/20250606171112.4013261-3-riel%40surriel.com
2025-06-17x86/microcode/AMD: Add TSA microcode SHAsBorislav Petkov (AMD)
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
2025-06-17x86/bugs: Add a Transient Scheduler Attacks mitigationBorislav Petkov (AMD)
Add the required features detection glue to bugs.c et all in order to support the TSA mitigation. Co-developed-by: Kim Phillips <kim.phillips@amd.com> Signed-off-by: Kim Phillips <kim.phillips@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
2025-06-16x86,fs/resctrl: Remove inappropriate references to cacheinfo in the resctrl ↵Qinyun Tan
subsystem In the resctrl subsystem's Sub-NUMA Cluster (SNC) mode, the rdt_mon_domain structure representing a NUMA node relies on the cacheinfo interface (rdt_mon_domain::ci) to store L3 cache information (e.g., shared_cpu_map) for monitoring. The L3 cache information of a SNC NUMA node determines which domains are summed for the "top level" L3-scoped events. rdt_mon_domain::ci is initialized using the first online CPU of a NUMA node. When this CPU goes offline, its shared_cpu_map is cleared to contain only the offline CPU itself. Subsequently, attempting to read counters via smp_call_on_cpu(offline_cpu) fails (and error ignored), returning zero values for "top-level events" without any error indication. Replace the cacheinfo references in struct rdt_mon_domain and struct rmid_read with the cacheinfo ID (a unique identifier for the L3 cache). rdt_domain_hdr::cpu_mask contains the online CPUs associated with that domain. When reading "top-level events", select a CPU from rdt_domain_hdr::cpu_mask and utilize its L3 shared_cpu_map to determine valid CPUs for reading RMID counter via the MSR interface. Considering all CPUs associated with the L3 cache improves the chances of picking a housekeeping CPU on which the counter reading work can be queued, avoiding an unnecessary IPI. Fixes: 328ea68874642 ("x86/resctrl: Prepare for new Sub-NUMA Cluster (SNC) monitor files") Signed-off-by: Qinyun Tan <qinyuntan@linux.alibaba.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250530182053.37502-2-qinyuntan@linux.alibaba.com
2025-06-16x86/bugs: Rename MDS machinery to something more genericBorislav Petkov (AMD)
It will be used by other x86 mitigations. No functional changes. Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
2025-05-29Merge tag 'x86_sgx_for_6.16-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull Intel software guard extension (SGX) updates from Dave Hansen: "A couple of x86/sgx changes. The first one is a no-brainer to use the (simple) SHA-256 library. For the second one, some folks doing testing noticed that SGX systems under memory pressure were inducing fatal machine checks at pretty unnerving rates, despite the SGX code having _some_ awareness of memory poison. It turns out that the SGX reclaim path was not checking for poison _and_ it always accesses memory to copy it around. Make sure that poisoned pages are not reclaimed" * tag 'x86_sgx_for_6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/sgx: Prevent attempts to reclaim poisoned pages x86/sgx: Use SHA-256 library API instead of crypto_shash API
2025-05-27Merge tag 'x86_mtrr_for_v6.16_rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull mtrr update from Borislav Petkov: "A single change to verify the presence of fixed MTRR ranges before accessing the respective MSRs" * tag 'x86_mtrr_for_v6.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mtrr: Check if fixed-range MTRRs exist in mtrr_save_fixed_ranges()
2025-05-27Merge tag 'x86_cache_for_v6.16_rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 resource control updates from Borislav Petkov: "Carve out the resctrl filesystem-related code into fs/resctrl/ so that multiple architectures can share the fs API for manipulating their respective hw resource control implementation. This is the second step in the work towards sharing the resctrl filesystem interface, the next one being plugging ARM's MPAM into the aforementioned fs API" * tag 'x86_cache_for_v6.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits) MAINTAINERS: Add reviewers for fs/resctrl x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl x86/resctrl: Always initialise rid field in rdt_resources_all[] x86/resctrl: Relax some asm #includes x86/resctrl: Prefer alloc(sizeof(*foo)) idiom in rdt_init_fs_context() x86/resctrl: Squelch whitespace anomalies in resctrl core code x86/resctrl: Move pseudo lock prototypes to include/linux/resctrl.h x86/resctrl: Fix types in resctrl_arch_mon_ctx_{alloc,free}() stubs x86/resctrl: Move enum resctrl_event_id to resctrl.h x86/resctrl: Move the filesystem bits to headers visible to fs/resctrl fs/resctrl: Add boiler plate for external resctrl code x86/resctrl: Add 'resctrl' to the title of the resctrl documentation x86/resctrl: Split trace.h x86/resctrl: Expand the width of domid by replacing mon_data_bits x86/resctrl: Add end-marker to the resctrl_event_id enum x86/resctrl: Move is_mba_sc() out of core.c x86/resctrl: Drop __init/__exit on assorted symbols x86/resctrl: Resctrl_exit() teardown resctrl but leave the mount point x86/resctrl: Check all domains are offline in resctrl_exit() x86/resctrl: Rename resctrl_sched_in() to begin with "resctrl_arch_" ...
2025-05-26Merge tag 'x86-cleanups-2025-05-25' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cleanups from Ingo Molnar: "Misc x86 cleanups: kernel-doc updates and a string API transition patch" * tag 'x86-cleanups-2025-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/power: hibernate: Fix W=1 build kernel-doc warnings x86/mm/pat: Fix W=1 build kernel-doc warning x86/CPU/AMD: Replace strcpy() with strscpy()
2025-05-21x86/bugs: Fix spectre_v2 mitigation default on IntelPawan Gupta
Commit 480e803dacf8 ("x86/bugs: Restructure spectre_v2 mitigation") inadvertently changed the spectre-v2 mitigation default from eIBRS to IBRS on Intel. While splitting the spectre_v2 mitigation in select/update/apply functions, eIBRS and IBRS selection logic was separated in select and update. This caused IBRS selection to not consider that eIBRS mitigation is already selected, fix it. Fixes: 480e803dacf8 ("x86/bugs: Restructure spectre_v2 mitigation") Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/20250520-eibrs-fix-v1-1-91bacd35ed09@linux.intel.com
2025-05-21x86/bugs: Restructure ITS mitigationDavid Kaplan
Restructure the ITS mitigation to use select/update/apply functions like the other mitigations. There is a particularly complex interaction between ITS and Retbleed as CDT (Call Depth Tracking) is a mitigation for both, and either its=stuff or retbleed=stuff will attempt to enable CDT. retbleed_update_mitigation() runs first and will check the necessary pre-conditions for CDT if either ITS or Retbleed stuffing is selected. If checks pass and ITS stuffing is selected, it will select stuffing for Retbleed as well. its_update_mitigation() runs after and will either select stuffing if retbleed stuffing was enabled, or fall back to the default (aligned thunks) if stuffing could not be enabled. Enablement of CDT is done exclusively in retbleed_apply_mitigation(). its_apply_mitigation() is only used to enable aligned thunks. Signed-off-by: David Kaplan <david.kaplan@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/20250516193212.128782-1-david.kaplan@amd.com
2025-05-21Merge tag 'v6.15-rc7' into x86/core, to pick up fixesIngo Molnar
Pick up build fixes from upstream to make this tree more testable. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2025-05-17Merge tag 'x86-urgent-2025-05-17' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull misc x86 fixes from Ingo Molnar: - Fix SEV-SNP kdump bugs - Update the email address of Alexey Makhalov in MAINTAINERS - Add the CPU feature flag for the Zen6 microarchitecture - Fix typo in system message * tag 'x86-urgent-2025-05-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm: Remove duplicated word in warning message x86/CPU/AMD: Add X86_FEATURE_ZEN6 x86/sev: Make sure pages are not skipped during kdump x86/sev: Do not touch VMSA pages during SNP guest memory kdump MAINTAINERS: Update Alexey Makhalov's email address x86/sev: Fix operator precedence in GHCB_MSR_VMPL_REQ_LEVEL macro
2025-05-17x86/bugs: Fix indentation due to ITS mergeBorislav Petkov (AMD)
No functional changes. Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2025-05-16x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrlJames Morse
Resctrl is a filesystem interface to hardware that provides cache allocation policy and bandwidth control for groups of tasks or CPUs. To support more than one architecture, resctrl needs to live in /fs/. Move the code that is concerned with the filesystem interface to /fs/resctrl. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com
2025-05-16x86/resctrl: Always initialise rid field in rdt_resources_all[]James Morse
x86 has an array, rdt_resources_all[], of all possible resources. The for-each-resource walkers depend on the rid field of all resources being initialised. If the array ever grows due to another architecture adding a resource type that is not defined on x86, the for-each-resources walkers will loop forever. Initialise all the rid values in resctrl_arch_late_init() before any for-each-resource walker can be called. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-24-james.morse@arm.com
2025-05-16x86/resctrl: Relax some asm #includesDave Martin
checkpatch.pl identifies some direct #includes of asm headers that can be satisfied by including the corresponding <linux/...> header instead. Fix them. No intentional functional change. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Peter Newman <peternewman@google.com> Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64 Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64 Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-23-james.morse@arm.com
2025-05-16x86/resctrl: Prefer alloc(sizeof(*foo)) idiom in rdt_init_fs_context()Dave Martin
rdt_init_fs_context() sizes a typed allocation using an explicit sizeof(type) expression, which checkpatch.pl complains about. Since this code is about to be factored out and made generic, this is a good opportunity to fix the code to size the allocation based on the target pointer instead, to reduce the chance of future mis- maintenance. Fix it. No functional change. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Peter Newman <peternewman@google.com> Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64 Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64 Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-22-james.morse@arm.com
2025-05-16x86/resctrl: Squelch whitespace anomalies in resctrl core codeDave Martin
checkpatch.pl complains about some whitespace anomalies in the resctrl core code. This doesn't matter, but since this code is about to be factored out and made generic, this is a good opportunity to fix these issues and so reduce future checkpatch fuzz. Fix them. No functional change. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Peter Newman <peternewman@google.com> Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64 Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64 Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-21-james.morse@arm.com
2025-05-16x86/resctrl: Move the filesystem bits to headers visible to fs/resctrlJames Morse
Once the filesystem parts of resctrl move to fs/resctrl, it cannot rely on definitions in x86's internal.h. Move definitions in internal.h that need to be shared between the filesystem and architecture code to header files that fs/resctrl can include. Doing this separately means the filesystem code only moves between files of the same name, instead of having these changes mixed in too. Co-developed-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64 Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Peter Newman <peternewman@google.com> Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64 Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64 Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-17-james.morse@arm.com
2025-05-16fs/resctrl: Add boiler plate for external resctrl codeJames Morse
Add Makefile and Kconfig for fs/resctrl. Add ARCH_HAS_CPU_RESCTRL for the common parts of the resctrl interface and make X86_CPU_RESCTRL select this. Adding an include of asm/resctrl.h to linux/resctrl.h allows the /fs/resctrl files to switch over to using this header instead. Co-developed-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64 Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Peter Newman <peternewman@google.com> Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64 Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64 Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-16-james.morse@arm.com
2025-05-16x86/cpu/intel: Rename CPUID(0x2) descriptors iterator parameterAhmed S. Darwish
The CPUID(0x2) descriptors iterator has been renamed from: for_each_leaf_0x2_entry() to: for_each_cpuid_0x2_desc() since it iterates over CPUID(0x2) cache and TLB "descriptors", not "entries". In the macro's x86/cpu call-site, rename the parameter denoting the parsed descriptor at each iteration from 'entry' to 'desc'. Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: x86-cpuid@lists.linux.dev Link: https://lore.kernel.org/r/20250508150240.172915-8-darwi@linutronix.de
2025-05-16x86/cacheinfo: Rename CPUID(0x2) descriptors iterator parameterAhmed S. Darwish
The CPUID(0x2) descriptors iterator has been renamed from: for_each_leaf_0x2_entry() to: for_each_cpuid_0x2_desc() since it iterates over CPUID(0x2) cache and TLB "descriptors", not "entries". In the macro's x86/cacheinfo call-site, rename the parameter denoting the parsed descriptor at each iteration from 'entry' to 'desc'. Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: x86-cpuid@lists.linux.dev Link: https://lore.kernel.org/r/20250508150240.172915-7-darwi@linutronix.de
2025-05-16x86/cpuid: Rename cpuid_get_leaf_0x2_regs() to cpuid_leaf_0x2()Ahmed S. Darwish
Rename the CPUID(0x2) register accessor function: cpuid_get_leaf_0x2_regs(regs) to: cpuid_leaf_0x2(regs) for consistency with other <cpuid/api.h> accessors that return full CPUID registers outputs like: cpuid_leaf(regs) cpuid_subleaf(regs) In the same vein, rename the CPUID(0x2) iteration macro: for_each_leaf_0x2_entry() to: for_each_cpuid_0x2_desc() to include "cpuid" in the macro name, and since what is iterated upon is CPUID(0x2) cache and TLB "descriptos", not "entries". Prefix an underscore to that iterator macro parameters, so that the newly renamed 'desc' parameter do not get mixed with "union leaf_0x2_regs :: desc[]" in the macro's implementation. Adjust all the affected call-sites accordingly. While at it, use "CPUID(0x2)" instead of "CPUID leaf 0x2" as this is the recommended style. No change in functionality intended. Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: x86-cpuid@lists.linux.dev Link: https://lore.kernel.org/r/20250508150240.172915-6-darwi@linutronix.de
2025-05-16x86/resctrl: Split trace.hJames Morse
trace.h contains all the tracepoints. After the move to /fs/resctrl, some of these will be left behind. All the pseudo_lock tracepoints remain part of the architecture. The lone tracepoint in monitor.c moves to /fs/resctrl. Split trace.h so that each C file includes a different trace header file. This means the trace header files are not modified when they are moved. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Peter Newman <peternewman@google.com> Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64 Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64 Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-14-james.morse@arm.com
2025-05-16x86/resctrl: Expand the width of domid by replacing mon_data_bitsJames Morse
MPAM platforms retrieve the cache-id property from the ACPI PPTT table. The cache-id field is 32 bits wide. Under resctrl, the cache-id becomes the domain-id, and is packed into the mon_data_bits union bitfield. The width of cache-id in this field is 14 bits. Expanding the union would break 32bit x86 platforms as this union is stored as the kernfs kn->priv pointer. This saved allocating memory for the priv data storage. The firmware on MPAM platforms have used the PPTT cache-id field to expose the interconnect's id for the cache, which is sparse and uses more than 14 bits. Use of this id is to enable PCIe direct cache injection hints. Using this feature with VFIO means the value provided by the ACPI table should be exposed to user-space. To support cache-id values greater than 14 bits, convert the mon_data_bits union to a structure. These are shared between control and monitor groups, and are allocated on first use. The list of allocated struct mon_data is free'd when the filesystem is umount()ed. Co-developed-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-13-james.morse@arm.com
2025-05-16x86/resctrl: Add end-marker to the resctrl_event_id enumJames Morse
The resctrl_event_id enum gives names to the counter event numbers on x86. These are used directly by resctrl. To allow the MPAM driver to keep an array of these the size of the enum needs to be known. Add a 'num_events' enum entry which can be used to size an array. This is added to the enum to reduce conflicts with another series, which in turn requires get_arch_mbm_state() to have a default case. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-12-james.morse@arm.com
2025-05-16x86/resctrl: Move is_mba_sc() out of core.cJames Morse
is_mba_sc() is defined in core.c, but has no callers there. It does not access any architecture private structures. Move this to rdtgroup.c where the majority of callers are. This makes the move of the filesystem code to /fs/ cleaner. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64 Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Peter Newman <peternewman@google.com> Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64 Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64 Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-11-james.morse@arm.com
2025-05-15x86/resctrl: Drop __init/__exit on assorted symbolsJames Morse
Because ARM's MPAM controls are probed using MMIO, resctrl can't be initialised until enough CPUs are online to have determined the system-wide supported num_closid. Arm64 also supports 'late onlined secondaries', where only a subset of CPUs are online during boot. These two combine to mean the MPAM driver may not be able to initialise resctrl until user-space has brought 'enough' CPUs online. To allow MPAM to initialise resctrl after __init text has been free'd, remove all the __init markings from resctrl. The existing __exit markings cause these functions to be removed by the linker as it has never been possible to build resctrl as a module. MPAM has an error interrupt which causes the driver to reset and disable itself. Remove the __exit markings to allow the MPAM driver to tear down resctrl when an error occurs. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64 Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Peter Newman <peternewman@google.com> Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64 Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64 Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-10-james.morse@arm.com
2025-05-15x86/resctrl: Resctrl_exit() teardown resctrl but leave the mount pointJames Morse
resctrl_exit() was intended for use when the 'resctrl' module was unloaded. resctrl can't be built as a module, and the kernfs helpers are not exported so this is unlikely to change. MPAM has an error interrupt which indicates the MPAM driver has gone haywire. Should this occur tasks could run with the wrong control values, leading to bad performance for important tasks. In this scenario the MPAM driver will reset the hardware, but it needs a way to tell resctrl that no further configuration should be attempted. In particular, moving tasks between control or monitor groups does not interact with the architecture code, so there is no opportunity for the arch code to indicate that the hardware is no-longer functioning. Using resctrl_exit() for this leaves the system in a funny state as resctrl is still mounted, but cannot be un-mounted because the sysfs directory that is typically used has been removed. Dave Martin suggests this may cause systemd trouble in the future as not all filesystems can be unmounted. Add calls to remove all the files and directories in resctrl, and remove the sysfs_remove_mount_point() call that leaves the system in a funny state. When triggered, this causes all the resctrl files to disappear. resctrl can be unmounted, but not mounted again. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64 Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Peter Newman <peternewman@google.com> Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64 Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64 Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-9-james.morse@arm.com
2025-05-15x86/resctrl: Check all domains are offline in resctrl_exit()James Morse
resctrl_exit() removes things like the resctrl mount point directory and unregisters the filesystem prior to freeing data structures that were allocated during resctrl_init(). This assumes that there are no online domains when resctrl_exit() is called. If any domain were online, the limbo or overflow handler could be scheduled to run. Add a check for any online control or monitor domains, and document that the architecture code is required to offline all monitor and control domains before calling resctrl_exit(). Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-8-james.morse@arm.com
2025-05-15x86/resctrl: Rename resctrl_sched_in() to begin with "resctrl_arch_"James Morse
resctrl_sched_in() loads the architecture specific CPU MSRs with the CLOSID and RMID values. This function was named before resctrl was split to have architecture specific code, and generic filesystem code. This function is obviously architecture specific, but does not begin with 'resctrl_arch_', making it the odd one out in the functions an architecture needs to support to enable resctrl. Rename it for consistency. This is purely cosmetic. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64 Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Peter Newman <peternewman@google.com> Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64 Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64 Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-7-james.morse@arm.com
2025-05-15x86/resctrl: Remove the limit on the number of CLOSIDAmit Singh Tomar
Resctrl allocates and finds free CLOSID values using the bits of a u32. This restricts the number of control groups that can be created by user-space. MPAM has an architectural limit of 2^16 CLOSID values, Intel x86 could be extended beyond 32 values. There is at least one MPAM platform which supports more than 32 CLOSID values. Replace the fixed size bitmap with calls to the bitmap API to allocate an array of a sufficient size. ffs() returns '1' for bit 0, hence the existing code subtracts 1 from the index to get the CLOSID value. find_first_bit() returns the bit number which does not need adjusting. [ morse: fixed the off-by-one in the allocator and the wrong not-found value. Removed the limit. Rephrase the commit message. ] Signed-off-by: Amit Singh Tomar <amitsinght@marvell.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Peter Newman <peternewman@google.com> Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64 Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64 Tested-by: Babu Moger <babu.moger@amd.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-6-james.morse@arm.com
2025-05-15x86/resctrl: Optimize cpumask_any_housekeeping()Yury Norov [NVIDIA]
With the lack of cpumask_any_andnot_but(), cpumask_any_housekeeping() has to abuse cpumask_nth() functions. Update cpumask_any_housekeeping() to use the new cpumask_any_but() and cpumask_any_andnot_but(). These two functions understand RESCTRL_PICK_ANY_CPU, which simplifies cpumask_any_housekeeping() significantly. Signed-off-by: Yury Norov [NVIDIA] <yury.norov@gmail.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: James Morse <james.morse@arm.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Reviewed-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: Fenghua Yu <fenghuay@nvidia.com> Tested-by: James Morse <james.morse@arm.com> Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250515165855.31452-5-james.morse@arm.com
2025-05-15x86/sgx: Prevent attempts to reclaim poisoned pagesAndrew Zaborowski
TL;DR: SGX page reclaim touches the page to copy its contents to secondary storage. SGX instructions do not gracefully handle machine checks. Despite this, the existing SGX code will try to reclaim pages that it _knows_ are poisoned. Avoid even trying to reclaim poisoned pages. The longer story: Pages used by an enclave only get epc_page->poison set in arch_memory_failure() but they currently stay on sgx_active_page_list until sgx_encl_release(), with the SGX_EPC_PAGE_RECLAIMER_TRACKED flag untouched. epc_page->poison is not checked in the reclaimer logic meaning that, if other conditions are met, an attempt will be made to reclaim an EPC page that was poisoned. This is bad because 1. we don't want that page to end up added to another enclave and 2. it is likely to cause one core to shut down and the kernel to panic. Specifically, reclaiming uses microcode operations including "EWB" which accesses the EPC page contents to encrypt and write them out to non-SGX memory. Those operations cannot handle MCEs in their accesses other than by putting the executing core into a special shutdown state (affecting both threads with HT.) The kernel will subsequently panic on the remaining cores seeing the core didn't enter MCE handler(s) in time. Call sgx_unmark_page_reclaimable() to remove the affected EPC page from sgx_active_page_list on memory error to stop it being considered for reclaiming. Testing epc_page->poison in sgx_reclaim_pages() would also work but I assume it's better to add code in the less likely paths. The affected EPC page is not added to &node->sgx_poison_page_list until later in sgx_encl_release()->sgx_free_epc_page() when it is EREMOVEd. Membership on other lists doesn't change to avoid changing any of the lists' semantics except for sgx_active_page_list. There's a "TBD" comment in arch_memory_failure() about pre-emptive actions, the goal here is not to address everything that it may imply. This also doesn't completely close the time window when a memory error notification will be fatal (for a not previously poisoned EPC page) -- the MCE can happen after sgx_reclaim_pages() has selected its candidates or even *inside* a microcode operation (actually easy to trigger due to the amount of time spent in them.) The spinlock in sgx_unmark_page_reclaimable() is safe because memory_failure() runs in process context and no spinlocks are held, explicitly noted in a mm/memory-failure.c comment. Signed-off-by: Andrew Zaborowski <andrew.zaborowski@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Tony Luck <tony.luck@intel.com> Cc: balrogg@gmail.com Cc: linux-sgx@vger.kernel.org Link: https://lore.kernel.org/r/20250508230429.456271-1-andrew.zaborowski@intel.com
2025-05-15x86/cpuid: Rename have_cpuid_p() to cpuid_feature()Ahmed S. Darwish
In order to let all the APIs under <cpuid/api.h> have a shared "cpuid_" namespace, rename have_cpuid_p() to cpuid_feature(). Adjust all call-sites accordingly. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: x86-cpuid@lists.linux.dev Link: https://lore.kernel.org/r/20250508150240.172915-4-darwi@linutronix.de
2025-05-15x86/cpuid: Set <asm/cpuid/api.h> as the main CPUID headerAhmed S. Darwish
The main CPUID header <asm/cpuid.h> was originally a storefront for the headers: <asm/cpuid/api.h> <asm/cpuid/leaf_0x2_api.h> Now that the latter CPUID(0x2) header has been merged into the former, there is no practical difference between <asm/cpuid.h> and <asm/cpuid/api.h>. Migrate all users to the <asm/cpuid/api.h> header, in preparation of the removal of <asm/cpuid.h>. Don't remove <asm/cpuid.h> just yet, in case some new code in -next started using it. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: x86-cpuid@lists.linux.dev Link: https://lore.kernel.org/r/20250508150240.172915-3-darwi@linutronix.de