summaryrefslogtreecommitdiff
path: root/arch/x86/kernel
AgeCommit message (Collapse)Author
2025-06-30Move FCH header to a location accessible by all archsMario Limonciello
A new header fch.h was created to store registers used by different AMD drivers. This header was included by i2c-piix4 in commit 624b0d5696a8 ("i2c: piix4, x86/platform: Move the SB800 PIIX4 FCH definitions to <asm/amd/fch.h>"). To prevent compile failures on non-x86 archs i2c-piix4 was set to only compile on x86 by commit 7e173eb82ae9717 ("i2c: piix4: Make CONFIG_I2C_PIIX4 dependent on CONFIG_X86"). This was not a good decision because loongarch and mips both actually support i2c-piix4 and set it enabled in the defconfig. Move the header to a location accessible by all architectures. Fixes: 624b0d5696a89 ("i2c: piix4, x86/platform: Move the SB800 PIIX4 FCH definitions to <asm/amd/fch.h>") Suggested-by: Hans de Goede <hansg@kernel.org> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Reviewed-by: Hans de Goede <hansg@kernel.org> Link: https://lore.kernel.org/r/20250610205817.3912944-1-superm1@kernel.org Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
2025-06-28x86/mce: Make sure CMCI banks are cleared during shutdown on IntelJP Kobryn
CMCI banks are not cleared during shutdown on Intel CPUs. As a side effect, when a kexec is performed, CPUs coming back online are unable to rediscover/claim these occupied banks which breaks MCE reporting. Clear the CPU ownership during shutdown via cmci_clear() so the banks can be reclaimed and MCE reporting will become functional once more. [ bp: Massage commit message. ] Reported-by: Aijay Adams <aijay@meta.com> Signed-off-by: JP Kobryn <inwardvessel@gmail.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com> Cc: <stable@kernel.org> Link: https://lore.kernel.org/20250627174935.95194-1-inwardvessel@gmail.com
2025-06-27x86/mce/amd: Fix threshold limit resetYazen Ghannam
The MCA threshold limit must be reset after servicing the interrupt. Currently, the restart function doesn't have an explicit check for this. It makes some assumptions based on the current limit and what's in the registers. These assumptions don't always hold, so the limit won't be reset in some cases. Make the reset condition explicit. Either an interrupt/overflow has occurred or the bank is being initialized. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/20250624-wip-mca-updates-v4-4-236dd74f645f@amd.com
2025-06-27x86/mce/amd: Add default names for MCA banks and blocksYazen Ghannam
Ensure that sysfs init doesn't fail for new/unrecognized bank types or if a bank has additional blocks available. Most MCA banks have a single thresholding block, so the block takes the same name as the bank. Unified Memory Controllers (UMCs) are a special case where there are two blocks and each has a unique name. However, the microarchitecture allows for five blocks. Any new MCA bank types with more than one block will be missing names for the extra blocks. The MCE sysfs will fail to initialize in this case. Fixes: 87a6d4091bd7 ("x86/mce/AMD: Update sysfs bank names for SMCA systems") Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/20250624-wip-mca-updates-v4-3-236dd74f645f@amd.com
2025-06-27x86/mce: Ensure user polling settings are honored when restarting timerYazen Ghannam
Users can disable MCA polling by setting the "ignore_ce" parameter or by setting "check_interval=0". This tells the kernel to *not* start the MCE timer on a CPU. If the user did not disable CMCI, then storms can occur. When these happen, the MCE timer will be started with a fixed interval. After the storm subsides, the timer's next interval is set to check_interval. This disregards the user's input through "ignore_ce" and "check_interval". Furthermore, if "check_interval=0", then the new timer will run faster than expected. Create a new helper to check these conditions and use it when a CMCI storm ends. [ bp: Massage. ] Fixes: 7eae17c4add5 ("x86/mce: Add per-bank CMCI storm mitigation") Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/20250624-wip-mca-updates-v4-2-236dd74f645f@amd.com
2025-06-26x86/mce: Don't remove sysfs if thresholding sysfs init failsYazen Ghannam
Currently, the MCE subsystem sysfs interface will be removed if the thresholding sysfs interface fails to be created. A common failure is due to new MCA bank types that are not recognized and don't have a short name set. The MCA thresholding feature is optional and should not break the common MCE sysfs interface. Also, new MCA bank types are occasionally introduced, and updates will be needed to recognize them. But likewise, this should not break the common sysfs interface. Keep the MCE sysfs interface regardless of the status of the thresholding sysfs interface. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Tony Luck <tony.luck@intel.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/20250624-wip-mca-updates-v4-1-236dd74f645f@amd.com
2025-06-26x86/bugs: Clean up SRSO microcode handlingDavid Kaplan
SRSO microcode only exists for Zen3/Zen4 CPUs. For those CPUs, the microcode is required for any mitigation other than Safe-RET to be effective. Safe-RET can still protect user->kernel and guest->host attacks without microcode. Clarify this in the code and ensure that SRSO_MITIGATION_UCODE_NEEDED is selected for any mitigation besides Safe-RET if the required microcode isn't present. Signed-off-by: David Kaplan <david.kaplan@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/20250625155805.600376-4-david.kaplan@amd.com
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/fpu/xstate: Add CET supervisor xfeature support as a guest-only featureYang Weijiang
== Background == CET defines two register states: CET user, which includes user-mode control registers, and CET supervisor, which consists of shadow-stack pointers for privilege levels 0-2. Current kernels disable shadow stacks in kernel mode, making the CET supervisor state unused and eliminating the need for context switching. == Problem == To virtualize CET for guests, KVM must accurately emulate hardware behavior. A key challenge arises because there is no CPUID flag to indicate that shadow stack is supported only in user mode. Therefore, KVM cannot assume guests will not enable shadow stacks in kernel mode and must preserve the CET supervisor state of vCPUs. == Solution == An initial proposal to manually save and restore CET supervisor states using raw RDMSR/WRMSR in KVM was rejected due to performance concerns and its impact on KVM's ABI. Instead, leveraging the kernel's FPU infrastructure for context switching was favored [1]. The main question then became whether to enable the CET supervisor state globally for all processes or restrict it to vCPU processes. This decision involves a trade-off between a 24-byte XSTATE buffer waste for all non-vCPU processes and approximately 100 lines of code complexity in the kernel [2]. The agreed approach is to first try this optimal solution [3], i.e., restricting the CET supervisor state to guest FPUs only and eliminating unnecessary space waste. The guest-only xfeature infrastructure has already been added. Now, introduce CET supervisor xstate support as the first guest-only feature to prepare for the upcoming CET virtualization in KVM. Signed-off-by: Yang Weijiang <weijiang.yang@intel.com> Signed-off-by: Chao Gao <chao.gao@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: John Allen <john.allen@amd.com> Link: https://lore.kernel.org/kvm/ZM1jV3UPL0AMpVDI@google.com/ [1] Link: https://lore.kernel.org/kvm/1c2fd06e-2e97-4724-80ab-8695aa4334e7@intel.com/ [2] Link: https://lore.kernel.org/kvm/2597a87b-1248-b8ce-ce60-94074bc67ea4@intel.com/ [3] Link: https://lore.kernel.org/all/20250522151031.426788-7-chao.gao%40intel.com
2025-06-24x86/fpu/xstate: Introduce "guest-only" supervisor xfeature setYang Weijiang
In preparation for upcoming CET virtualization support, the CET supervisor state will be added as a "guest-only" feature, since it is required only by KVM (i.e., guest FPUs). Establish the infrastructure for "guest-only" features. Define a new XFEATURE_MASK_GUEST_SUPERVISOR mask to specify features that are enabled by default in guest FPUs but not in host FPUs. Specifically, for any bit in this set, permission is granted and XSAVE space is allocated during vCPU creation. Non-guest FPUs cannot enable guest-only features, even dynamically, and no XSAVE space will be allocated for them. The mask is currently empty, but this will be changed by a subsequent patch. Co-developed-by: Chao Gao <chao.gao@intel.com> Signed-off-by: Chao Gao <chao.gao@intel.com> Signed-off-by: Yang Weijiang <weijiang.yang@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Reviewed-by: John Allen <john.allen@amd.com> Link: https://lore.kernel.org/all/20250522151031.426788-6-chao.gao%40intel.com
2025-06-24x86/fpu: Remove xfd argument from __fpstate_reset()Chao Gao
The initial values for fpstate::xfd differ between guest and host fpstates. Currently, the initial values are passed as an argument to __fpstate_reset(). But, __fpstate_reset() already assigns different default features and sizes based on the type of fpstates (i.e., guest or host). So, handle fpstate::xfd in a similar way to highlight the differences in the initial xfd value between guest and host fpstates Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Chao Gao <chao.gao@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: John Allen <john.allen@amd.com> Link: https://lore.kernel.org/all/aBuf7wiiDT0Wflhk@google.com/ Link: https://lore.kernel.org/all/20250522151031.426788-5-chao.gao%40intel.com
2025-06-24x86/fpu: Initialize guest fpstate and FPU pseudo container from guest defaultsChao Gao
fpu_alloc_guest_fpstate() currently uses host defaults to initialize guest fpstate and pseudo containers. Guest defaults were introduced to differentiate the features and sizes of host and guest FPUs. Switch to using guest defaults instead. Adjust __fpstate_reset() to handle different defaults for host and guest FPUs. And to distinguish between the types of FPUs, move the initialization of indicators (is_guest and is_valloc) before the reset. Suggested-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Chao Gao <chao.gao@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Reviewed-by: John Allen <john.allen@amd.com> Link: https://lore.kernel.org/all/20250522151031.426788-4-chao.gao%40intel.com
2025-06-24x86/fpu: Initialize guest FPU permissions from guest defaultsChao Gao
Currently, fpu->guest_perm is copied from fpu->perm, which is derived from fpu_kernel_cfg.default_features. Guest defaults were introduced to differentiate the features and sizes of host and guest FPUs. Copying guest FPU permissions from the host will lead to inconsistencies between the guest default features and permissions. Initialize guest FPU permissions from guest defaults instead of host defaults. This ensures that any changes to guest default features are automatically reflected in guest permissions, which in turn guarantees that fpstate_realloc() allocates a correctly sized XSAVE buffer for guest FPUs. Suggested-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Chao Gao <chao.gao@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Reviewed-by: John Allen <john.allen@amd.com> Link: https://lore.kernel.org/all/20250522151031.426788-3-chao.gao%40intel.com
2025-06-24x86/fpu/xstate: Differentiate default features for host and guest FPUsChao Gao
Currently, guest and host FPUs share the same default features. However, the CET supervisor xstate is the first feature that needs to be enabled exclusively for guest FPUs. Enabling it for host FPUs leads to a waste of 24 bytes in the XSAVE buffer. To support "guest-only" features, add a new structure to hold the default features and sizes for guest FPUs to clearly differentiate them from those for host FPUs. Add two helpers to provide the default feature masks for guest and host FPUs. Default features are derived by applying the masks to the maximum supported features. Note that, 1) for now, guest_default_mask() and host_default_mask() are identical. This will change in a follow-up patch once guest permissions, default xfeatures, and fpstate size are all converted to use the guest defaults. 2) only supervisor features will diverge between guest FPUs and host FPUs, while user features will remain the same [1][2]. So, the new vcpu_fpu_config struct does not include default user features and size for the UABI buffer. An alternative approach is adding a guest_only_xfeatures member to fpu_kernel_cfg and adding two helper functions to calculate the guest default xfeatures and size. However, calculating these defaults at runtime would introduce unnecessary overhead. Suggested-by: Chang S. Bae <chang.seok.bae@intel.com> Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Chao Gao <chao.gao@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: John Allen <john.allen@amd.com> Link: https://lore.kernel.org/kvm/aAwdQ759Y6V7SGhv@google.com/ [1] Link: https://lore.kernel.org/kvm/9ca17e1169805f35168eb722734fbf3579187886.camel@intel.com/ [2] Link: https://lore.kernel.org/all/20250522151031.426788-2-chao.gao%40intel.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
2025-06-23Merge 6.16-rc3 into driver-core-nextGreg Kroah-Hartman
We need the driver-core fixes that are in 6.16-rc3 into here as well to build on top of. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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
2025-06-20Merge tag 'drm-misc-next-2025-06-19' of ↵Dave Airlie
https://gitlab.freedesktop.org/drm/misc/kernel into drm-next drm-misc-next for 6.17: UAPI Changes: - Add Task Information for the wedge API Cross-subsystem Changes: Core Changes: - Fix warnings related to export.h - fbdev: Make CONFIG_FIRMWARE_EDID available on all architectures - fence: Fix UAF issues - format-helper: Improve tests Driver Changes: - ivpu: Add turbo flag, Add Wildcat Lake Support - rz-du: Improve MIPI-DSI Support - vmwgfx: fence improvement Signed-off-by: Dave Airlie <airlied@redhat.com> From: Maxime Ripard <mripard@redhat.com> Link: https://lore.kernel.org/r/20250619-perfect-industrious-whippet-8ed3db@houat
2025-06-18x86/alternatives: Fix int3 handling failure from broken text_poke arrayMasami Hiramatsu (Google)
Since smp_text_poke_single() does not expect there is another text_poke request is queued, it can make text_poke_array not sorted or cause a buffer overflow on the text_poke_array.vec[]. This will cause an Oops in int3 because of bsearch failing; CPU 0 CPU 1 CPU 2 ----- ----- ----- smp_text_poke_batch_add() smp_text_poke_single() <<-- Adds out of order <int3> [Fails o find address in text_poke_array ] OOPS! Or unhandled page fault because of a buffer overflow; CPU 0 CPU 1 ----- ----- smp_text_poke_batch_add() <<+ ... | smp_text_poke_batch_add() <<-- Adds TEXT_POKE_ARRAY_MAX times. smp_text_poke_single() { __smp_text_poke_batch_add() <<-- Adds entry at TEXT_POKE_ARRAY_MAX + 1 smp_text_poke_batch_finish() [Unhandled page fault because text_poke_array.nr_entries is overwritten] BUG! } Use smp_text_poke_batch_add() instead of __smp_text_poke_batch_add() so that it correctly flush the queue if needed. Closes: https://lore.kernel.org/all/CA+G9fYsLu0roY3DV=tKyqP7FEKbOEETRvTDhnpPxJGbA=Cg+4w@mail.gmail.com/ Fixes: c8976ade0c1b ("x86/alternatives: Simplify smp_text_poke_single() by using tp_vec and existing APIs") Reported-by: Linux Kernel Functional Testing <lkft@linaro.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Link: https://lkml.kernel.org/r/\ 175020512308.3582717.13631440385506146631.stgit@mhiramat.tok.corp.google.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/its: Fix an ifdef typo in its_alloc()Lukas Bulwahn
Commit a82b26451de1 ("x86/its: explicitly manage permissions for ITS pages") reworks its_alloc() and introduces a typo in an ifdef conditional, referring to CONFIG_MODULE instead of CONFIG_MODULES. Fix this typo in its_alloc(). Fixes: a82b26451de1 ("x86/its: explicitly manage permissions for ITS pages") Signed-off-by: Lukas Bulwahn <lukas.bulwahn@redhat.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lore.kernel.org/all/20250616100432.22941-1-lukas.bulwahn%40redhat.com
2025-06-17x86/process: Move the buffer clearing before MONITORBorislav Petkov (AMD)
Move the VERW clearing before the MONITOR so that VERW doesn't disarm it and the machine never enters C1. Original idea by Kim Phillips <kim.phillips@amd.com>. Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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>
2025-06-17sysfs: treewide: switch back to attribute_group::bin_attrsThomas Weißschuh
The normal bin_attrs field can now handle const pointers. This makes the _new variant unnecessary. Switch all users back. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://lore.kernel.org/r/20250530-sysfs-const-bin_attr-final-v3-4-724bfcf05b99@weissschuh.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-17sysfs: treewide: switch back to bin_attribute::read()/write()Thomas Weißschuh
The bin_attribute argument of bin_attribute::read() is now const. This makes the _new() callbacks unnecessary. Switch all users back. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://lore.kernel.org/r/20250530-sysfs-const-bin_attr-final-v3-3-724bfcf05b99@weissschuh.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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
2025-06-16Merge tag 'x86_urgent_for_6.16-rc3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Dave Hansen: "This is a pretty scattered set of fixes. The majority of them are further fixups around the recent ITS mitigations. The rest don't really have a coherent story: - Some flavors of Xen PV guests don't support large pages, but the set_memory.c code assumes all CPUs support them. Avoid problems with a quick CPU feature check. - The TDX code has some wrappers to help retry calls to the TDX module. They use function pointers to assembly functions and the compiler usually generates direct CALLs. But some new compilers, plus -Os turned them in to indirect CALLs and the assembly code was not annotated for indirect calls. Force inlining of the helper to fix it up. - Last, a FRED issue showed up when single-stepping. It's fine when using an external debugger, but was getting stuck returning from a SIGTRAP handler otherwise. Clear the FRED 'swevent' bit to ensure that forward progress is made" * tag 'x86_urgent_for_6.16-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Revert "mm/execmem: Unify early execmem_cache behaviour" x86/its: explicitly manage permissions for ITS pages x86/its: move its_pages array to struct mod_arch_specific x86/Kconfig: only enable ROX cache in execmem when STRICT_MODULE_RWX is set x86/mm/pat: don't collapse pages without PSE set x86/virt/tdx: Avoid indirect calls to TDX assembly functions selftests/x86: Add a test to detect infinite SIGTRAP handler loop x86/fred/signal: Prevent immediate repeat of single step trap on return from SIGTRAP handler
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>
2025-06-16video: Make global edid_info depend on CONFIG_FIRMWARE_EDIDThomas Zimmermann
Protect global edid_info behind CONFIG_FIRMWARE_EDID and remove the config tests for CONFIG_X86. Makes edid_info available iff its option has been enabled. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Helge Deller <deller@gmx.de> Link: https://lore.kernel.org/r/20250602075537.137759-3-tzimmermann@suse.de
2025-06-13Merge branch 'pm-cpuidle'Rafael J. Wysocki
Merge cpuidle updates for 6.16-rc2: - Update data types of variables passed as arguments to mwait_idle_with_hints() to match the function definition after recent changes (Uros Bizjak). - Eliminate mwait_play_dead_cpuid_hint() again after reverting its elimination during the merge window due to a problem with handling "dead" SMT siblings, but this time prevent leaving them in C1 after initialization by taking them online and back offline when a proper cpuidle driver for the platform has been registered (Rafael Wysocki). * pm-cpuidle: intel_idle: Update arguments of mwait_idle_with_hints() Reapply "x86/smp: Eliminate mwait_play_dead_cpuid_hint()" ACPI: processor: Rescan "dead" SMT siblings during initialization intel_idle: Rescan "dead" SMT siblings during initialization x86/smp: PM/hibernate: Split arch_resume_nosmt() intel_idle: Use subsys_initcall_sync() for initialization
2025-06-11x86/its: explicitly manage permissions for ITS pagesPeter Zijlstra (Intel)
execmem_alloc() sets permissions differently depending on the kernel configuration, CPU support for PSE and whether a page is allocated before or after mark_rodata_ro(). Add tracking for pages allocated for ITS when patching the core kernel and make sure the permissions for ITS pages are explicitly managed for both kernel and module allocations. Fixes: 872df34d7c51 ("x86/its: Use dynamic thunks for indirect branches") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Co-developed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Nikolay Borisov <nik.borisov@suse.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20250603111446.2609381-5-rppt@kernel.org
2025-06-11x86/its: move its_pages array to struct mod_arch_specificMike Rapoport (Microsoft)
The of pages with ITS thunks allocated for modules are tracked by an array in 'struct module'. Since this is very architecture specific data structure, move it to 'struct mod_arch_specific'. No functional changes. Fixes: 872df34d7c51 ("x86/its: Use dynamic thunks for indirect branches") Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20250603111446.2609381-4-rppt@kernel.org
2025-06-09x86/fred/signal: Prevent immediate repeat of single step trap on return from ↵Xin Li (Intel)
SIGTRAP handler Clear the software event flag in the augmented SS to prevent immediate repeat of single step trap on return from SIGTRAP handler if the trap flag (TF) is set without an external debugger attached. Following is a typical single-stepping flow for a user process: 1) The user process is prepared for single-stepping by setting RFLAGS.TF = 1. 2) When any instruction in user space completes, a #DB is triggered. 3) The kernel handles the #DB and returns to user space, invoking the SIGTRAP handler with RFLAGS.TF = 0. 4) After the SIGTRAP handler finishes, the user process performs a sigreturn syscall, restoring the original state, including RFLAGS.TF = 1. 5) Goto step 2. According to the FRED specification: A) Bit 17 in the augmented SS is designated as the software event flag, which is set to 1 for FRED event delivery of SYSCALL, SYSENTER, or INT n. B) If bit 17 of the augmented SS is 1 and ERETU would result in RFLAGS.TF = 1, a single-step trap will be pending upon completion of ERETU. In step 4) above, the software event flag is set upon the sigreturn syscall, and its corresponding ERETU would restore RFLAGS.TF = 1. This combination causes a pending single-step trap upon completion of ERETU. Therefore, another #DB is triggered before any user space instruction is executed, which leads to an infinite loop in which the SIGTRAP handler keeps being invoked on the same user space IP. Fixes: 14619d912b65 ("x86/fred: FRED entry/exit and dispatch code") 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> Tested-by: Sohil Mehta <sohil.mehta@intel.com> Cc:stable@vger.kernel.org Link: https://lore.kernel.org/all/20250609084054.2083189-2-xin%40zytor.com
2025-06-08Merge tag 'x86-urgent-2025-06-08' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Thomas Gleixner: "A small set of x86 fixes: - Cure IO bitmap inconsistencies A failed fork cleans up all resources of the newly created thread via exit_thread(). exit_thread() invokes io_bitmap_exit() which does the IO bitmap cleanups, which unfortunately assume that the cleanup is related to the current task, which is obviously bogus. Make it work correctly - A lockdep fix in the resctrl code removed the clearing of the command buffer in two places, which keeps stale error messages around. Bring them back. - Remove unused trace events" * tag 'x86-urgent-2025-06-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: fs/resctrl: Restore the rdt_last_cmd_clear() calls after acquiring rdtgroup_mutex x86/iopl: Cure TIF_IO_BITMAP inconsistencies x86/fpu: Remove unused trace events
2025-06-07Merge tag 'kbuild-v6.16' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Add support for the EXPORT_SYMBOL_GPL_FOR_MODULES() macro, which exports a symbol only to specified modules - Improve ABI handling in gendwarfksyms - Forcibly link lib-y objects to vmlinux even if CONFIG_MODULES=n - Add checkers for redundant or missing <linux/export.h> inclusion - Deprecate the extra-y syntax - Fix a genksyms bug when including enum constants from *.symref files * tag 'kbuild-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (28 commits) genksyms: Fix enum consts from a reference affecting new values arch: use always-$(KBUILD_BUILTIN) for vmlinux.lds kbuild: set y instead of 1 to KBUILD_{BUILTIN,MODULES} efi/libstub: use 'targets' instead of extra-y in Makefile module: make __mod_device_table__* symbols static scripts/misc-check: check unnecessary #include <linux/export.h> when W=1 scripts/misc-check: check missing #include <linux/export.h> when W=1 scripts/misc-check: add double-quotes to satisfy shellcheck kbuild: move W=1 check for scripts/misc-check to top-level Makefile scripts/tags.sh: allow to use alternative ctags implementation kconfig: introduce menu type enum docs: symbol-namespaces: fix reST warning with literal block kbuild: link lib-y objects to vmlinux forcibly even when CONFIG_MODULES=n tinyconfig: enable CONFIG_LD_DEAD_CODE_DATA_ELIMINATION docs/core-api/symbol-namespaces: drop table of contents and section numbering modpost: check forbidden MODULE_IMPORT_NS("module:") at compile time kbuild: move kbuild syntax processing to scripts/Makefile.build Makefile: remove dependency on archscripts for header installation Documentation/kbuild: Add new gendwarfksyms kABI rules Documentation/kbuild: Drop section numbers ...
2025-06-07Reapply "x86/smp: Eliminate mwait_play_dead_cpuid_hint()"Rafael J. Wysocki
Revert commit 70523f335734 ("Revert "x86/smp: Eliminate mwait_play_dead_cpuid_hint()"") to reapply the changes from commit 96040f7273e2 ("x86/smp: Eliminate mwait_play_dead_cpuid_hint()") reverted by it. Previously, these changes caused idle power to rise on systems booting with "nosmt" in the kernel command line because they effectively caused "dead" SMT siblings to remain in idle state C1 after executing the HLT instruction, which prevented the processor from reaching package idle states deeper than PC2 going forward. Now, the "dead" SMT siblings are rescanned after initializing a proper cpuidle driver for the processor (either intel_idle or ACPI idle), at which point they are able to enter a sufficiently deep idle state in native_play_dead() via cpuidle, so the code changes in question can be reapplied. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Link: https://patch.msgid.link/7813065.EvYhyI6sBW@rjwysocki.net
2025-06-07x86/smp: PM/hibernate: Split arch_resume_nosmt()Rafael J. Wysocki
Move the inner part of the arch_resume_nosmt() code into a separate function called arch_cpu_rescan_dead_smt_siblings(), so it can be used in other places where "dead" SMT siblings may need to be taken online and offline again in order to get into deep idle states. No intentional functional impact. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Link: https://patch.msgid.link/3361688.44csPzL39Z@rjwysocki.net [ rjw: Prevent build issues with CONFIG_SMP unset ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-06-07arch: use always-$(KBUILD_BUILTIN) for vmlinux.ldsMasahiro Yamada
The extra-y syntax is deprecated. Instead, use always-$(KBUILD_BUILTIN), which behaves equivalently. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Johannes Berg <johannes@sipsolutions.net> Reviewed-by: Nicolas Schier <n.schier@avm.de>
2025-06-03Merge tag 'hyperv-next-signed-20250602' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux Pull hyperv updates from Wei Liu: - Support for Virtual Trust Level (VTL) on arm64 (Roman Kisel) - Fixes for Hyper-V UIO driver (Long Li) - Fixes for Hyper-V PCI driver (Michael Kelley) - Select CONFIG_SYSFB for Hyper-V guests (Michael Kelley) - Documentation updates for Hyper-V VMBus (Michael Kelley) - Enhance logging for hv_kvp_daemon (Shradha Gupta) * tag 'hyperv-next-signed-20250602' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (23 commits) Drivers: hv: Always select CONFIG_SYSFB for Hyper-V guests Drivers: hv: vmbus: Add comments about races with "channels" sysfs dir Documentation: hyperv: Update VMBus doc with new features and info PCI: hv: Remove unnecessary flex array in struct pci_packet Drivers: hv: Remove hv_alloc/free_* helpers Drivers: hv: Use kzalloc for panic page allocation uio_hv_generic: Align ring size to system page uio_hv_generic: Use correct size for interrupt and monitor pages Drivers: hv: Allocate interrupt and monitor pages aligned to system page boundary arch/x86: Provide the CPU number in the wakeup AP callback x86/hyperv: Fix APIC ID and VP index confusion in hv_snp_boot_ap() PCI: hv: Get vPCI MSI IRQ domain from DeviceTree ACPI: irq: Introduce acpi_get_gsi_dispatcher() Drivers: hv: vmbus: Introduce hv_get_vmbus_root_device() Drivers: hv: vmbus: Get the IRQ number from DeviceTree dt-bindings: microsoft,vmbus: Add interrupt and DMA coherence properties arm64, x86: hyperv: Report the VTL the system boots in arm64: hyperv: Initialize the Virtual Trust Level field Drivers: hv: Provide arch-neutral implementation of get_vtl() Drivers: hv: Enable VTL mode for arm64 ...