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9543f6e2 |
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17-Apr-2024 |
Eric Biggers <ebiggers@google.com> |
x86/cpufeatures: Fix dependencies for GFNI, VAES, and VPCLMULQDQ Fix cpuid_deps[] to list the correct dependencies for GFNI, VAES, and VPCLMULQDQ. These features don't depend on AVX512, and there exist CPUs that support these features but not AVX512. GFNI actually doesn't even depend on AVX. This prevents GFNI from being unnecessarily disabled if AVX is disabled to mitigate the GDS vulnerability. This also prevents all three features from being unnecessarily disabled if AVX512VL (or its dependency AVX512F) were to be disabled, but it looks like there isn't any case where this happens anyway. Fixes: c128dbfa0f87 ("x86/cpufeatures: Enable new SSE/AVX/AVX512 CPU features") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lore.kernel.org/r/20240417060434.47101-1-ebiggers@kernel.org
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51c158f7 |
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05-Dec-2023 |
H. Peter Anvin (Intel) <hpa@zytor.com> |
x86/cpufeatures: Add the CPU feature bit for FRED Any FRED enabled CPU will always have the following features as its baseline: 1) LKGS, load attributes of the GS segment but the base address into the IA32_KERNEL_GS_BASE MSR instead of the GS segment’s descriptor cache. 2) WRMSRNS, non-serializing WRMSR for faster MSR writes. Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com> Signed-off-by: Xin Li <xin3.li@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Shan Kang <shan.kang@intel.com> Link: https://lore.kernel.org/r/20231205105030.8698-7-xin3.li@intel.com
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701fb66d |
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12-Jun-2023 |
Rick Edgecombe <rick.p.edgecombe@intel.com> |
x86/cpufeatures: Add CPU feature flags for shadow stacks The Control-Flow Enforcement Technology contains two related features, one of which is Shadow Stacks. Future patches will utilize this feature for shadow stack support in KVM, so add a CPU feature flags for Shadow Stacks (CPUID.(EAX=7,ECX=0):ECX[bit 7]). To protect shadow stack state from malicious modification, the registers are only accessible in supervisor mode. This implementation context-switches the registers with XSAVES. Make X86_FEATURE_SHSTK depend on XSAVES. The shadow stack feature, enumerated by the CPUID bit described above, encompasses both supervisor and userspace support for shadow stack. In near future patches, only userspace shadow stack will be enabled. In expectation of future supervisor shadow stack support, create a software CPU capability to enumerate kernel utilization of userspace shadow stack support. This user shadow stack bit should depend on the HW "shstk" capability and that logic will be implemented in future patches. Co-developed-by: Yu-cheng Yu <yu-cheng.yu@intel.com> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Tested-by: Pengfei Xu <pengfei.xu@intel.com> Tested-by: John Allen <john.allen@amd.com> Tested-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/all/20230613001108.3040476-9-rick.p.edgecombe%40intel.com
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#
78335aac |
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13-Jan-2023 |
Babu Moger <babu.moger@amd.com> |
x86/cpufeatures: Add Bandwidth Monitoring Event Configuration feature flag Newer AMD processors support the new feature Bandwidth Monitoring Event Configuration (BMEC). The feature support is identified via CPUID Fn8000_0020_EBX_x0[3]: EVT_CFG - Bandwidth Monitoring Event Configuration (BMEC) The bandwidth monitoring events mbm_total_bytes and mbm_local_bytes are set to count all the total and local reads/writes, respectively. With the introduction of slow memory, the two counters are not enough to count all the different types of memory events. Therefore, BMEC provides the option to configure mbm_total_bytes and mbm_local_bytes to count the specific type of events. Each BMEC event has a configuration MSR which contains one field for each bandwidth type that can be used to configure the bandwidth event to track any combination of supported bandwidth types. The event will count requests from every bandwidth type bit that is set in the corresponding configuration register. Following are the types of events supported: ==== ======================================================== Bits Description ==== ======================================================== 6 Dirty Victims from the QOS domain to all types of memory 5 Reads to slow memory in the non-local NUMA domain 4 Reads to slow memory in the local NUMA domain 3 Non-temporal writes to non-local NUMA domain 2 Non-temporal writes to local NUMA domain 1 Reads to memory in the non-local NUMA domain 0 Reads to memory in the local NUMA domain ==== ======================================================== By default, the mbm_total_bytes configuration is set to 0x7F to count all the event types and the mbm_local_bytes configuration is set to 0x15 to count all the local memory events. Feature description is available in the specification, "AMD64 Technology Platform Quality of Service Extensions, Revision: 1.03 Publication" at https://bugzilla.kernel.org/attachment.cgi?id=301365 Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/r/20230113152039.770054-5-babu.moger@amd.com
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#
16a7fe37 |
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31-Oct-2022 |
Kai Huang <kai.huang@intel.com> |
KVM/VMX: Allow exposing EDECCSSA user leaf function to KVM guest The new Asynchronous Exit (AEX) notification mechanism (AEX-notify) allows one enclave to receive a notification in the ERESUME after the enclave exit due to an AEX. EDECCSSA is a new SGX user leaf function (ENCLU[EDECCSSA]) to facilitate the AEX notification handling. The new EDECCSSA is enumerated via CPUID(EAX=0x12,ECX=0x0):EAX[11]. Besides Allowing reporting the new AEX-notify attribute to KVM guests, also allow reporting the new EDECCSSA user leaf function to KVM guests so the guest can fully utilize the AEX-notify mechanism. Similar to existing X86_FEATURE_SGX1 and X86_FEATURE_SGX2, introduce a new scattered X86_FEATURE_SGX_EDECCSSA bit for the new EDECCSSA, and report it in KVM's supported CPUIDs. Note, no additional KVM enabling is required to allow the guest to use EDECCSSA. It's impossible to trap ENCLU (without completely preventing the guest from using SGX). Advertise EDECCSSA as supported purely so that userspace doesn't need to special case EDECCSSA, i.e. doesn't need to manually check host CPUID. The inability to trap ENCLU also means that KVM can't prevent the guest from using EDECCSSA, but that virtualization hole is benign as far as KVM is concerned. EDECCSSA is simply a fancy way to modify internal enclave state. More background about how do AEX-notify and EDECCSSA work: SGX maintains a Current State Save Area Frame (CSSA) for each enclave thread. When AEX happens, the enclave thread context is saved to the CSSA and the CSSA is increased by 1. For a normal ERESUME which doesn't deliver AEX notification, it restores the saved thread context from the previously saved SSA and decreases the CSSA. If AEX-notify is enabled for one enclave, the ERESUME acts differently. Instead of restoring the saved thread context and decreasing the CSSA, it acts like EENTER which doesn't decrease the CSSA but establishes a clean slate thread context using the CSSA for the enclave to handle the notification. After some handling, the enclave must discard the "new-established" SSA and switch back to the previously saved SSA (upon AEX). Otherwise, the enclave will run out of SSA space upon further AEXs and eventually fail to run. To solve this problem, the new EDECCSSA essentially decreases the CSSA. It can be used by the enclave notification handler to switch back to the previous saved SSA when needed, i.e. after it handles the notification. Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Sean Christopherson <seanjc@google.com> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lore.kernel.org/all/20221101022422.858944-1-kai.huang%40intel.com
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#
30d02551 |
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02-Nov-2021 |
Dave Hansen <dave.hansen@linux.intel.com> |
x86/fpu: Optimize out sigframe xfeatures when in init state tl;dr: AMX state is ~8k. Signal frames can have space for this ~8k and each signal entry writes out all 8k even if it is zeros. Skip writing zeros for AMX to speed up signal delivery by about 4% overall when AMX is in its init state. This is a user-visible change to the sigframe ABI. == Hardware XSAVE Background == XSAVE state components may be tracked by the processor as being in their initial configuration. Software can detect which features are in this configuration by looking at the XSTATE_BV field in an XSAVE buffer or with the XGETBV(1) instruction. Both the XSAVE and XSAVEOPT instructions enumerate features s being in the initial configuration via the XSTATE_BV field in the XSAVE header, However, XSAVEOPT declines to actually write features in their initial configuration to the buffer. XSAVE writes the feature unconditionally, regardless of whether it is in the initial configuration or not. Basically, XSAVE users never need to inspect XSTATE_BV to determine if the feature has been written to the buffer. XSAVEOPT users *do* need to inspect XSTATE_BV. They might also need to clear out the buffer if they want to make an isolated change to the state, like modifying one register. == Software Signal / XSAVE Background == Signal frames have historically been written with XSAVE itself. Each state is written in its entirety, regardless of being in its initial configuration. In other words, the signal frame ABI uses the XSAVE behavior, not the XSAVEOPT behavior. == Problem == This means that any application which has acquired permission to use AMX via ARCH_REQ_XCOMP_PERM will write 8k of state to the signal frame. This 8k write will occur even when AMX was in its initial configuration and software *knows* this because of XSTATE_BV. This problem also exists to a lesser degree with AVX-512 and its 2k of state. However, AVX-512 use does not require ARCH_REQ_XCOMP_PERM and is more likely to have existing users which would be impacted by any change in behavior. == Solution == Stop writing out AMX xfeatures which are in their initial state to the signal frame. This effectively makes the signal frame XSAVE buffer look as if it were written with a combination of XSAVEOPT and XSAVE behavior. Userspace which handles XSAVEOPT- style buffers should be able to handle this naturally. For now, include only the AMX xfeatures: XTILE and XTILEDATA in this new behavior. These require new ABI to use anyway, which makes their users very unlikely to be broken. This XSAVEOPT-like behavior should be expected for all future dynamic xfeatures. It may also be extended to legacy features like AVX-512 in the future. Only attempt this optimization on systems with dynamic features. Disable dynamic feature support (XFD) if XGETBV1 is unavailable by adding a CPUID dependency. This has been measured to reduce the *overall* cycle cost of signal delivery by about 4%. Fixes: 2308ee57d93d ("x86/fpu/amx: Enable the AMX feature in 64-bit mode") Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: "Chang S. Bae" <chang.seok.bae@intel.com> Link: https://lore.kernel.org/r/20211102224750.FA412E26@davehans-spike.ostc.intel.com
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2308ee57 |
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21-Oct-2021 |
Chang S. Bae <chang.seok.bae@intel.com> |
x86/fpu/amx: Enable the AMX feature in 64-bit mode Add the AMX state components in XFEATURE_MASK_USER_SUPPORTED and the TILE_DATA component to the dynamic states and update the permission check table accordingly. This is only effective on 64 bit kernels as for 32bit kernels XFEATURE_MASK_TILE is defined as 0. TILE_DATA is caller-saved state and the only dynamic state. Add build time sanity check to ensure the assumption that every dynamic feature is caller- saved. Make AMX state depend on XFD as it is dynamic feature. Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20211021225527.10184-24-chang.seok.bae@intel.com
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#
c3511016 |
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21-Oct-2021 |
Chang S. Bae <chang.seok.bae@intel.com> |
x86/cpufeatures: Add eXtended Feature Disabling (XFD) feature bit Intel's eXtended Feature Disable (XFD) feature is an extension of the XSAVE architecture. XFD allows the kernel to enable a feature state in XCR0 and to receive a #NM trap when a task uses instructions accessing that state. This is going to be used to postpone the allocation of a larger XSTATE buffer for a task to the point where it is actually using a related instruction after the permission to use that facility has been granted. XFD is not used by the kernel, but only applied to userspace. This is a matter of policy as the kernel knows how a fpstate is reallocated and the XFD state. The compacted XSAVE format is adjustable for dynamic features. Make XFD depend on XSAVES. Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20211021225527.10184-13-chang.seok.bae@intel.com
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#
b8921dcc |
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19-Mar-2021 |
Sean Christopherson <seanjc@google.com> |
x86/cpufeatures: Add SGX1 and SGX2 sub-features Add SGX1 and SGX2 feature flags, via CPUID.0x12.0x0.EAX, as scattered features, since adding a new leaf for only two bits would be wasteful. As part of virtualizing SGX, KVM will expose the SGX CPUID leafs to its guest, and to do so correctly needs to query hardware and kernel support for SGX1 and SGX2. Suppress both SGX1 and SGX2 from /proc/cpuinfo. SGX1 basically means SGX, and for SGX2 there is no concrete use case of using it in /proc/cpuinfo. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Dave Hansen <dave.hansen@intel.com> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lkml.kernel.org/r/d787827dbfca6b3210ac3e432e3ac1202727e786.1616136308.git.kai.huang@intel.com
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#
e9a15a40 |
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19-Mar-2021 |
Kai Huang <kai.huang@intel.com> |
x86/cpufeatures: Make SGX_LC feature bit depend on SGX bit Move SGX_LC feature bit to CPUID dependency table to make clearing all SGX feature bits easier. Also remove clear_sgx_caps() since it is just a wrapper of setup_clear_cpu_cap(X86_FEATURE_SGX) now. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Sean Christopherson <seanjc@google.com> Acked-by: Dave Hansen <dave.hansen@intel.com> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lkml.kernel.org/r/5d4220fd0a39f52af024d3fa166231c1d498dd10.1616136308.git.kai.huang@intel.com
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#
e1b35da5 |
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07-Dec-2020 |
Kyung Min Park <kyung.min.park@intel.com> |
x86: Enumerate AVX512 FP16 CPUID feature flag Enumerate AVX512 Half-precision floating point (FP16) CPUID feature flag. Compared with using FP32, using FP16 cut the number of bits required for storage in half, reducing the exponent from 8 bits to 5, and the mantissa from 23 bits to 10. Using FP16 also enables developers to train and run inference on deep learning models fast when all precision or magnitude (FP32) is not needed. A processor supports AVX512 FP16 if CPUID.(EAX=7,ECX=0):EDX[bit 23] is present. The AVX512 FP16 requires AVX512BW feature be implemented since the instructions for manipulating 32bit masks are associated with AVX512BW. The only in-kernel usage of this is kvm passthrough. The CPU feature flag is shown as "avx512_fp16" in /proc/cpuinfo. Signed-off-by: Kyung Min Park <kyung.min.park@intel.com> Acked-by: Dave Hansen <dave.hansen@intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Message-Id: <20201208033441.28207-2-kyung.min.park@intel.com> Acked-by: Borislav Petkov <bp@suse.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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ff4f8281 |
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15-Sep-2020 |
Fenghua Yu <fenghua.yu@intel.com> |
x86/cpufeatures: Enumerate ENQCMD and ENQCMDS instructions Work submission instruction comes in two flavors. ENQCMD can be called both in ring 3 and ring 0 and always uses the contents of a PASID MSR when shipping the command to the device. ENQCMDS allows a kernel driver to submit commands on behalf of a user process. The driver supplies the PASID value in ENQCMDS. There isn't any usage of ENQCMD in the kernel as of now. The CPU feature flag is shown as "enqcmd" in /proc/cpuinfo. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Link: https://lkml.kernel.org/r/1600187413-163670-5-git-send-email-fenghua.yu@intel.com
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e48cb1a3 |
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24-Aug-2020 |
Fenghua Yu <fenghua.yu@intel.com> |
x86/resctrl: Enumerate per-thread MBA controls Some systems support per-thread Memory Bandwidth Allocation (MBA) which applies a throttling delay value to each hardware thread instead of to a core. Per-thread MBA is enumerated by CPUID. No feature flag is shown in /proc/cpuinfo. User applications need to check a resctrl throttling mode info file to know if the feature is supported. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Babu Moger <babu.moger@amd.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lkml.kernel.org/r/1598296281-127595-2-git-send-email-fenghua.yu@intel.com
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#
018ebca8 |
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17-Jul-2019 |
Gayatri Kammela <gayatri.kammela@intel.com> |
x86/cpufeatures: Enable a new AVX512 CPU feature Add a new AVX512 instruction group/feature for enumeration in /proc/cpuinfo: AVX512_VP2INTERSECT. CPUID.(EAX=7,ECX=0):EDX[bit 8] AVX512_VP2INTERSECT Detailed information of CPUID bits for this feature can be found in the Intel Architecture Intsruction Set Extensions Programming Reference document (refer to Table 1-2). A copy of this document is available at https://bugzilla.kernel.org/show_bug.cgi?id=204215. Signed-off-by: Gayatri Kammela <gayatri.kammela@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190717234632.32673-3-gayatri.kammela@intel.com
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1e0c08e3 |
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17-Jul-2019 |
Gayatri Kammela <gayatri.kammela@intel.com> |
cpu/cpuid-deps: Add a tab to cpuid dependent features Improve code readability by adding a tab between the elements of each structure in an array of cpuid-dep struct so longer feature names will fit. Signed-off-by: Gayatri Kammela <gayatri.kammela@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190717234632.32673-2-gayatri.kammela@intel.com
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#
9838e3bf |
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03-Jul-2019 |
Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
x86/fpu: Make 'no387' and 'nofxsr' command line options useful The command line option `no387' is designed to disable the FPU entirely. This only 'works' with CONFIG_MATH_EMULATION enabled. But on 64bit this cannot work because user space expects SSE to work which required basic FPU support. MATH_EMULATION does not help because SSE is not emulated. The command line option `nofxsr' should also be limited to 32bit because FXSR is part of the required flags on 64bit so turning it off is not possible. Clearing X86_FEATURE_FPU without emulation enabled will not work anyway and hang in fpu__init_system_early_generic() before the console is enabled. Setting additioal dependencies, ensures that the CPU still boots on a modern CPU. Otherwise, dropping FPU will leave FXSR enabled causing the kernel to crash early in fpu__init_system_mxcsr(). With XSAVE support it will crash in fpu__init_cpu_xstate(). The problem is that xsetbv() with XMM set and SSE cleared is not allowed. That means XSAVE has to be disabled. The XSAVE support is disabled in fpu__init_system_xstate_size_legacy() but it is too late. It can be removed, it has been added in commit 1f999ab5a1360 ("x86, xsave: Disable xsave in i387 emulation mode") to use `no387' on a CPU with XSAVE support. All this happens before console output. After hat, the next possible crash is in RAID6 detect code because MMX remained enabled. With a 3DNOW enabled config it will explode in memcpy() for instance due to kernel_fpu_begin() but this is unconditionally enabled. This is enough to boot a Debian Wheezy on a 32bit qemu "host" CPU which supports everything up to XSAVES, AVX2 without 3DNOW. Later, Debian increased the minimum requirements to i686 which means it does not boot userland atleast due to CMOV. After masking the additional features it still keeps SSE4A and 3DNOW* enabled (if present on the host) but those are unused in the kernel. Restrict `no387' and `nofxsr' otions to 32bit only. Add dependencies for FPU, FXSR to additionaly mask CMOV, MMX, XSAVE if FXSR or FPU is cleared. Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190703083247.57kjrmlxkai3vpw3@linutronix.de
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#
b302e4b1 |
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17-Jun-2019 |
Fenghua Yu <fenghua.yu@intel.com> |
x86/cpufeatures: Enumerate the new AVX512 BFLOAT16 instructions AVX512 BFLOAT16 instructions support 16-bit BFLOAT16 floating-point format (BF16) for deep learning optimization. BF16 is a short version of 32-bit single-precision floating-point format (FP32) and has several advantages over 16-bit half-precision floating-point format (FP16). BF16 keeps FP32 accumulation after multiplication without loss of precision, offers more than enough range for deep learning training tasks, and doesn't need to handle hardware exception. AVX512 BFLOAT16 instructions are enumerated in CPUID.7.1:EAX[bit 5] AVX512_BF16. CPUID.7.1:EAX contains only feature bits. Reuse the currently empty word 12 as a pure features word to hold the feature bits including AVX512_BF16. Detailed information of the CPUID bit and AVX512 BFLOAT16 instructions can be found in the latest Intel Architecture Instruction Set Extensions and Future Features Programming Reference. [ bp: Check CPUID(7) subleaf validity before accessing subleaf 1. ] Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: "Chang S. Bae" <chang.seok.bae@intel.com> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nadav Amit <namit@vmware.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Pavel Tatashin <pasha.tatashin@oracle.com> Cc: Peter Feiner <pfeiner@google.com> Cc: Radim Krcmar <rkrcmar@redhat.com> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: Robert Hoo <robert.hu@linux.intel.com> Cc: "Sean J Christopherson" <sean.j.christopherson@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Lendacky <Thomas.Lendacky@amd.com> Cc: x86 <x86@kernel.org> Link: https://lkml.kernel.org/r/1560794416-217638-3-git-send-email-fenghua.yu@intel.com
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#
acec0ce0 |
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19-Jun-2019 |
Fenghua Yu <fenghua.yu@intel.com> |
x86/cpufeatures: Combine word 11 and 12 into a new scattered features word It's a waste for the four X86_FEATURE_CQM_* feature bits to occupy two whole feature bits words. To better utilize feature words, re-define word 11 to host scattered features and move the four X86_FEATURE_CQM_* features into Linux defined word 11. More scattered features can be added in word 11 in the future. Rename leaf 11 in cpuid_leafs to CPUID_LNX_4 to reflect it's a Linux-defined leaf. Rename leaf 12 as CPUID_DUMMY which will be replaced by a meaningful name in the next patch when CPUID.7.1:EAX occupies world 12. Maximum number of RMID and cache occupancy scale are retrieved from CPUID.0xf.1 after scattered CQM features are enumerated. Carve out the code into a separate function. KVM doesn't support resctrl now. So it's safe to move the X86_FEATURE_CQM_* features to scattered features word 11 for KVM. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Aaron Lewis <aaronlewis@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Babu Moger <babu.moger@amd.com> Cc: "Chang S. Bae" <chang.seok.bae@intel.com> Cc: "Sean J Christopherson" <sean.j.christopherson@intel.com> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Juergen Gross <jgross@suse.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: kvm ML <kvm@vger.kernel.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nadav Amit <namit@vmware.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Pavel Tatashin <pasha.tatashin@oracle.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Ravi V Shankar <ravi.v.shankar@intel.com> Cc: Sherry Hurwitz <sherry.hurwitz@amd.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Lendacky <Thomas.Lendacky@amd.com> Cc: x86 <x86@kernel.org> Link: https://lkml.kernel.org/r/1560794416-217638-2-git-send-email-fenghua.yu@intel.com
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52586b08 |
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07-Mar-2018 |
Ralf Ramsauer <ralf.ramsauer@oth-regensburg.de> |
x86/cpuid: Switch to 'static const' specifier This is the only spot where the 'const static' specifier is used; everywhere else 'static const' is preferred, as static should be the first specifier. This is just a cosmetic fix that aligns this, no functional change. Signed-off-by: Ralf Ramsauer <ralf.ramsauer@oth-regensburg.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andi Kleen <ak@linux.intel.com> Cc: Gayatri Kammela <gayatri.kammela@intel.com> Link: https://lkml.kernel.org/r/20180307160734.6691-1-ralf.ramsauer@oth-regensburg.de
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06dd688d |
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02-Nov-2017 |
Thomas Gleixner <tglx@linutronix.de> |
x86/cpuid: Replace set/clear_bit32() Peter pointed out that the set/clear_bit32() variants are broken in various aspects. Replace them with open coded set/clear_bit() and type cast cpu_info::x86_capability as it's done in all other places throughout x86. Fixes: 0b00de857a64 ("x86/cpuid: Add generic table for CPUID dependencies") Reported-by: Peter Ziljstra <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andi Kleen <ak@linux.intel.com>
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c128dbfa |
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30-Oct-2017 |
Gayatri Kammela <gayatri.kammela@intel.com> |
x86/cpufeatures: Enable new SSE/AVX/AVX512 CPU features Add a few new SSE/AVX/AVX512 instruction groups/features for enumeration in /proc/cpuinfo: AVX512_VBMI2, GFNI, VAES, VPCLMULQDQ, AVX512_VNNI, AVX512_BITALG. CPUID.(EAX=7,ECX=0):ECX[bit 6] AVX512_VBMI2 CPUID.(EAX=7,ECX=0):ECX[bit 8] GFNI CPUID.(EAX=7,ECX=0):ECX[bit 9] VAES CPUID.(EAX=7,ECX=0):ECX[bit 10] VPCLMULQDQ CPUID.(EAX=7,ECX=0):ECX[bit 11] AVX512_VNNI CPUID.(EAX=7,ECX=0):ECX[bit 12] AVX512_BITALG Detailed information of CPUID bits for these features can be found in the Intel Architecture Instruction Set Extensions and Future Features Programming Interface document (refer to Table 1-1. and Table 1-2.). A copy of this document is available at https://bugzilla.kernel.org/show_bug.cgi?id=197239 Signed-off-by: Gayatri Kammela <gayatri.kammela@intel.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andi Kleen <andi.kleen@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi Shankar <ravi.v.shankar@intel.com> Cc: Ricardo Neri <ricardo.neri@intel.com> Cc: Yang Zhong <yang.zhong@intel.com> Cc: bp@alien8.de Link: http://lkml.kernel.org/r/1509412829-23380-1-git-send-email-gayatri.kammela@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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57b8b1a1 |
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18-Oct-2017 |
Thomas Gleixner <tglx@linutronix.de> |
x86/cpuid: Prevent out of bound access in do_clear_cpu_cap() do_clear_cpu_cap() allocates a bitmap to keep track of disabled feature dependencies. That bitmap is sized NCAPINTS * BITS_PER_INIT. The possible 'features' which can be handed in are larger than this, because after the capabilities the bug 'feature' bits occupy another 32bit. Not really obvious... So clearing any of the misfeature bits, as 32bit does for the F00F bug, accesses that bitmap out of bounds thereby corrupting the stack. Size the bitmap proper and add a sanity check to catch accidental out of bound access. Fixes: 0b00de857a64 ("x86/cpuid: Add generic table for CPUID dependencies") Reported-by: kernel test robot <xiaolong.ye@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andi Kleen <ak@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Link: https://lkml.kernel.org/r/20171018022023.GA12058@yexl-desktop
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0b00de85 |
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13-Oct-2017 |
Andi Kleen <ak@linux.intel.com> |
x86/cpuid: Add generic table for CPUID dependencies Some CPUID features depend on other features. Currently it's possible to to clear dependent features, but not clear the base features, which can cause various interesting problems. This patch implements a generic table to describe dependencies between CPUID features, to be used by all code that clears CPUID. Some subsystems (like XSAVE) had an own implementation of this, but it's better to do it all in a single place for everyone. Then clear_cpu_cap and setup_clear_cpu_cap always look up this table and clear all dependencies too. This is intended to be a practical table: only for features that make sense to clear. If someone for example clears FPU, or other features that are essentially part of the required base feature set, not much is going to work. Handling that is right now out of scope. We're only handling features which can be usefully cleared. Signed-off-by: Andi Kleen <ak@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Jonathan McDowell <noodles@earth.li> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20171013215645.23166-3-andi@firstfloor.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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