blaster4385/linux-IllusionX/Documentation/ABI/testing/sysfs-devices-system-cpu, branch v6.13

Document/kexec: generalize crash hotplug description

2024-09-02T03:43:37Z

Commit 79365026f869 ("crash: add a new kexec flag for hotplug support") generalizes the crash hotplug support to allow architectures to update multiple kexec segments on CPU/Memory hotplug and not just elfcorehdr. Therefore, update the relevant kernel documentation to reflect the same. No functional change. Link: https://lkml.kernel.org/r/20240812041651.703156-1-sourabhjain@linux.ibm.com Signed-off-by: Sourabh Jain Reviewed-by: Petr Tesarik Acked-by: Baoquan He Cc: Hari Bathini Cc: Petr Tesarik Cc: Sourabh Jain Cc: Jonathan Corbet Signed-off-by: Andrew Morton

cpu/SMT: Enable SMT only if a core is online

2024-08-13T00:31:24Z

If a core is offline then enabling SMT should not online CPUs of this core. By enabling SMT, what is intended is either changing the SMT value from "off" to "on" or setting the SMT level (threads per core) from a lower to higher value. On PowerPC the ppc64_cpu utility can be used, among other things, to perform the following functions: ppc64_cpu --cores-on # Get the number of online cores ppc64_cpu --cores-on=X # Put exactly X cores online ppc64_cpu --offline-cores=X[,Y,...] # Put specified cores offline ppc64_cpu --smt={on|off|value} # Enable, disable or change SMT level If the user has decided to offline certain cores, enabling SMT should not online CPUs in those cores. This patch fixes the issue and changes the behaviour as described, by introducing an arch specific function topology_is_core_online(). It is currently implemented only for PowerPC. Fixes: 73c58e7e1412 ("powerpc: Add HOTPLUG_SMT support") Reported-by: Tyrel Datwyler Closes: https://groups.google.com/g/powerpc-utils-devel/c/wrwVzAAnRlI/m/5KJSoqP4BAAJ Signed-off-by: Nysal Jan K.A Reviewed-by: Shrikanth Hegde Reviewed-by: Thomas Gleixner Signed-off-by: Michael Ellerman Link: https://msgid.link/20240731030126.956210-2-nysal@linux.ibm.com

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

2024-07-16T18:12:25Z

Pull x86 SEV updates from Borislav Petkov: - Add support for running the kernel in a SEV-SNP guest, over a Secure VM Service Module (SVSM). When running over a SVSM, different services can run at different protection levels, apart from the guest OS but still within the secure SNP environment. They can provide services to the guest, like a vTPM, for example. This series adds the required facilities to interface with such a SVSM module. - The usual fixlets, refactoring and cleanups [ And as always: "SEV" is AMD's "Secure Encrypted Virtualization". I can't be the only one who gets all the newer x86 TLA's confused, can I? - Linus ] * tag 'x86_sev_for_v6.11_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Documentation/ABI/configfs-tsm: Fix an unexpected indentation silly x86/sev: Do RMP memory coverage check after max_pfn has been set x86/sev: Move SEV compilation units virt: sev-guest: Mark driver struct with __refdata to prevent section mismatch x86/sev: Allow non-VMPL0 execution when an SVSM is present x86/sev: Extend the config-fs attestation support for an SVSM x86/sev: Take advantage of configfs visibility support in TSM fs/configfs: Add a callback to determine attribute visibility sev-guest: configfs-tsm: Allow the privlevel_floor attribute to be updated virt: sev-guest: Choose the VMPCK key based on executing VMPL x86/sev: Provide guest VMPL level to userspace x86/sev: Provide SVSM discovery support x86/sev: Use the SVSM to create a vCPU when not in VMPL0 x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0 x86/sev: Use kernel provided SVSM Calling Areas x86/sev: Check for the presence of an SVSM in the SNP secrets page x86/irqflags: Provide native versions of the local_irq_save()/restore()

cpumask: Add enabled cpumask for present CPUs that can be brought online

2024-06-28T17:38:33Z

The 'offline' file in sysfs shows all offline CPUs, including those that aren't present. User-space is expected to remove not-present CPUs from this list to learn which CPUs could be brought online. CPUs can be present but not-enabled. These CPUs can't be brought online until the firmware policy changes, which comes with an ACPI notification that will register the CPUs. With only the offline and present files, user-space is unable to determine which CPUs it can try to bring online. Add a new CPU mask that shows this based on all the registered CPUs. Signed-off-by: James Morse Tested-by: Miguel Luis Tested-by: Vishnu Pajjuri Tested-by: Jianyong Wu Acked-by: Thomas Gleixner Signed-off-by: Russell King (Oracle) Reviewed-by: Gavin Shan Signed-off-by: Jonathan Cameron Link: https://lore.kernel.org/r/20240529133446.28446-20-Jonathan.Cameron@huawei.com Signed-off-by: Catalin Marinas

x86/sev: Provide guest VMPL level to userspace

2024-06-17T18:42:57Z

Requesting an attestation report from userspace involves providing the VMPL level for the report. Currently any value from 0-3 is valid because Linux enforces running at VMPL0. When an SVSM is present, though, Linux will not be running at VMPL0 and only VMPL values starting at the VMPL level Linux is running at to 3 are valid. In order to allow userspace to determine the minimum VMPL value that can be supplied to an attestation report, create a sysfs entry that can be used to retrieve the current VMPL level of the kernel. [ bp: Add CONFIG_SYSFS ifdeffery. ] Signed-off-by: Tom Lendacky Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/fff846da0d8d561f9fdaf297dcf8cd907545a25b.1717600736.git.thomas.lendacky@amd.com

Documentation: Fix the address of the linuxppc-dev mailing list

2024-05-06T12:05:18Z

This list was moved many years ago. Signed-off-by: Stephen Rothwell Signed-off-by: Michael Ellerman Link: https://msgid.link/20240503121012.3ba5000b@canb.auug.org.au

x86/rfds: Mitigate Register File Data Sampling (RFDS)

2024-03-11T20:13:48Z

RFDS is a CPU vulnerability that may allow userspace to infer kernel stale data previously used in floating point registers, vector registers and integer registers. RFDS only affects certain Intel Atom processors. Intel released a microcode update that uses VERW instruction to clear the affected CPU buffers. Unlike MDS, none of the affected cores support SMT. Add RFDS bug infrastructure and enable the VERW based mitigation by default, that clears the affected buffers just before exiting to userspace. Also add sysfs reporting and cmdline parameter "reg_file_data_sampling" to control the mitigation. For details see: Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst Signed-off-by: Pawan Gupta Signed-off-by: Dave Hansen Reviewed-by: Thomas Gleixner Acked-by: Josh Poimboeuf

Documentation: Drop or replace remaining mentions of IA64

2023-09-11T08:13:18Z

Drop or update mentions of IA64, as appropriate. Signed-off-by: Ard Biesheuvel

Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-08-29T21:53:51Z

Pull non-MM updates from Andrew Morton: - An extensive rework of kexec and crash Kconfig from Eric DeVolder ("refactor Kconfig to consolidate KEXEC and CRASH options") - kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a couple of macros to args.h") - gdb feature work from Kuan-Ying Lee ("Add GDB memory helper commands") - vsprintf inclusion rationalization from Andy Shevchenko ("lib/vsprintf: Rework header inclusions") - Switch the handling of kdump from a udev scheme to in-kernel handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory hot un/plug") - Many singleton patches to various parts of the tree * tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits) document while_each_thread(), change first_tid() to use for_each_thread() drivers/char/mem.c: shrink character device's devlist[] array x86/crash: optimize CPU changes crash: change crash_prepare_elf64_headers() to for_each_possible_cpu() crash: hotplug support for kexec_load() x86/crash: add x86 crash hotplug support crash: memory and CPU hotplug sysfs attributes kexec: exclude elfcorehdr from the segment digest crash: add generic infrastructure for crash hotplug support crash: move a few code bits to setup support of crash hotplug kstrtox: consistently use _tolower() kill do_each_thread() nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse scripts/bloat-o-meter: count weak symbol sizes treewide: drop CONFIG_EMBEDDED lockdep: fix static memory detection even more lib/vsprintf: declare no_hash_pointers in sprintf.h lib/vsprintf: split out sprintf() and friends kernel/fork: stop playing lockless games for exe_file replacement adfs: delete unused "union adfs_dirtail" definition ...

Merge tag 'smp-core-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2023-08-28T22:04:43Z

Pull CPU hotplug updates from Thomas Gleixner: "Updates for the CPU hotplug core: - Support partial SMT enablement. So far the sysfs SMT control only allows to toggle between SMT on and off. That's sufficient for x86 which usually has at max two threads except for the Xeon PHI platform which has four threads per core Though PowerPC has up to 16 threads per core and so far it's only possible to control the number of enabled threads per core via a command line option. There is some way to control this at runtime, but that lacks enforcement and the usability is awkward This update expands the sysfs interface and the core infrastructure to accept numerical values so PowerPC can build SMT runtime control for partial SMT enablement on top The core support has also been provided to the PowerPC maintainers who added the PowerPC related changes on top - Minor cleanups and documentation updates" * tag 'smp-core-2023-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Documentation: core-api/cpuhotplug: Fix state names cpu/hotplug: Remove unused function declaration cpu_set_state_online() cpu/SMT: Fix cpu_smt_possible() comment cpu/SMT: Allow enabling partial SMT states via sysfs cpu/SMT: Create topology_smt_thread_allowed() cpu/SMT: Remove topology_smt_supported() cpu/SMT: Store the current/max number of threads cpu/SMT: Move smt/control simple exit cases earlier cpu/SMT: Move SMT prototypes into cpu_smt.h cpu/hotplug: Remove dependancy against cpu_primary_thread_mask