linux/kernel/power, branch v6.13

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2024-11-24T00:00:50Z

Pull kvm updates from Paolo Bonzini: "The biggest change here is eliminating the awful idea that KVM had of essentially guessing which pfns are refcounted pages. The reason to do so was that KVM needs to map both non-refcounted pages (for example BARs of VFIO devices) and VM_PFNMAP/VM_MIXMEDMAP VMAs that contain refcounted pages. However, the result was security issues in the past, and more recently the inability to map VM_IO and VM_PFNMAP memory that _is_ backed by struct page but is not refcounted. In particular this broke virtio-gpu blob resources (which directly map host graphics buffers into the guest as "vram" for the virtio-gpu device) with the amdgpu driver, because amdgpu allocates non-compound higher order pages and the tail pages could not be mapped into KVM. This requires adjusting all uses of struct page in the per-architecture code, to always work on the pfn whenever possible. The large series that did this, from David Stevens and Sean Christopherson, also cleaned up substantially the set of functions that provided arch code with the pfn for a host virtual addresses. The previous maze of twisty little passages, all different, is replaced by five functions (__gfn_to_page, __kvm_faultin_pfn, the non-__ versions of these two, and kvm_prefetch_pages) saving almost 200 lines of code. ARM: - Support for stage-1 permission indirection (FEAT_S1PIE) and permission overlays (FEAT_S1POE), including nested virt + the emulated page table walker - Introduce PSCI SYSTEM_OFF2 support to KVM + client driver. This call was introduced in PSCIv1.3 as a mechanism to request hibernation, similar to the S4 state in ACPI - Explicitly trap + hide FEAT_MPAM (QoS controls) from KVM guests. As part of it, introduce trivial initialization of the host's MPAM context so KVM can use the corresponding traps - PMU support under nested virtualization, honoring the guest hypervisor's trap configuration and event filtering when running a nested guest - Fixes to vgic ITS serialization where stale device/interrupt table entries are not zeroed when the mapping is invalidated by the VM - Avoid emulated MMIO completion if userspace has requested synchronous external abort injection - Various fixes and cleanups affecting pKVM, vCPU initialization, and selftests LoongArch: - Add iocsr and mmio bus simulation in kernel. - Add in-kernel interrupt controller emulation. - Add support for virtualization extensions to the eiointc irqchip. PPC: - Drop lingering and utterly obsolete references to PPC970 KVM, which was removed 10 years ago. - Fix incorrect documentation references to non-existing ioctls RISC-V: - Accelerate KVM RISC-V when running as a guest - Perf support to collect KVM guest statistics from host side s390: - New selftests: more ucontrol selftests and CPU model sanity checks - Support for the gen17 CPU model - List registers supported by KVM_GET/SET_ONE_REG in the documentation x86: - Cleanup KVM's handling of Accessed and Dirty bits to dedup code, improve documentation, harden against unexpected changes. Even if the hardware A/D tracking is disabled, it is possible to use the hardware-defined A/D bits to track if a PFN is Accessed and/or Dirty, and that removes a lot of special cases. - Elide TLB flushes when aging secondary PTEs, as has been done in x86's primary MMU for over 10 years. - Recover huge pages in-place in the TDP MMU when dirty page logging is toggled off, instead of zapping them and waiting until the page is re-accessed to create a huge mapping. This reduces vCPU jitter. - Batch TLB flushes when dirty page logging is toggled off. This reduces the time it takes to disable dirty logging by ~3x. - Remove the shrinker that was (poorly) attempting to reclaim shadow page tables in low-memory situations. - Clean up and optimize KVM's handling of writes to MSR_IA32_APICBASE. - Advertise CPUIDs for new instructions in Clearwater Forest - Quirk KVM's misguided behavior of initialized certain feature MSRs to their maximum supported feature set, which can result in KVM creating invalid vCPU state. E.g. initializing PERF_CAPABILITIES to a non-zero value results in the vCPU having invalid state if userspace hides PDCM from the guest, which in turn can lead to save/restore failures. - Fix KVM's handling of non-canonical checks for vCPUs that support LA57 to better follow the "architecture", in quotes because the actual behavior is poorly documented. E.g. most MSR writes and descriptor table loads ignore CR4.LA57 and operate purely on whether the CPU supports LA57. - Bypass the register cache when querying CPL from kvm_sched_out(), as filling the cache from IRQ context is generally unsafe; harden the cache accessors to try to prevent similar issues from occuring in the future. The issue that triggered this change was already fixed in 6.12, but was still kinda latent. - Advertise AMD_IBPB_RET to userspace, and fix a related bug where KVM over-advertises SPEC_CTRL when trying to support cross-vendor VMs. - Minor cleanups - Switch hugepage recovery thread to use vhost_task. These kthreads can consume significant amounts of CPU time on behalf of a VM or in response to how the VM behaves (for example how it accesses its memory); therefore KVM tried to place the thread in the VM's cgroups and charge the CPU time consumed by that work to the VM's container. However the kthreads did not process SIGSTOP/SIGCONT, and therefore cgroups which had KVM instances inside could not complete freezing. Fix this by replacing the kthread with a PF_USER_WORKER thread, via the vhost_task abstraction. Another 100+ lines removed, with generally better behavior too like having these threads properly parented in the process tree. - Revert a workaround for an old CPU erratum (Nehalem/Westmere) that didn't really work; there was really nothing to work around anyway: the broken patch was meant to fix nested virtualization, but the PERF_GLOBAL_CTRL MSR is virtualized and therefore unaffected by the erratum. - Fix 6.12 regression where CONFIG_KVM will be built as a module even if asked to be builtin, as long as neither KVM_INTEL nor KVM_AMD is 'y'. x86 selftests: - x86 selftests can now use AVX. Documentation: - Use rST internal links - Reorganize the introduction to the API document Generic: - Protect vcpu->pid accesses outside of vcpu->mutex with a rwlock instead of RCU, so that running a vCPU on a different task doesn't encounter long due to having to wait for all CPUs become quiescent. In general both reads and writes are rare, but userspace that supports confidential computing is introducing the use of "helper" vCPUs that may jump from one host processor to another. Those will be very happy to trigger a synchronize_rcu(), and the effect on performance is quite the disaster" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (298 commits) KVM: x86: Break CONFIG_KVM_X86's direct dependency on KVM_INTEL || KVM_AMD KVM: x86: add back X86_LOCAL_APIC dependency Revert "KVM: VMX: Move LOAD_IA32_PERF_GLOBAL_CTRL errata handling out of setup_vmcs_config()" KVM: x86: switch hugepage recovery thread to vhost_task KVM: x86: expose MSR_PLATFORM_INFO as a feature MSR x86: KVM: Advertise CPUIDs for new instructions in Clearwater Forest Documentation: KVM: fix malformed table irqchip/loongson-eiointc: Add virt extension support LoongArch: KVM: Add irqfd support LoongArch: KVM: Add PCHPIC user mode read and write functions LoongArch: KVM: Add PCHPIC read and write functions LoongArch: KVM: Add PCHPIC device support LoongArch: KVM: Add EIOINTC user mode read and write functions LoongArch: KVM: Add EIOINTC read and write functions LoongArch: KVM: Add EIOINTC device support LoongArch: KVM: Add IPI user mode read and write function LoongArch: KVM: Add IPI read and write function LoongArch: KVM: Add IPI device support LoongArch: KVM: Add iocsr and mmio bus simulation in kernel KVM: arm64: Pass on SVE mapping failures ...

PM: EM: Add min/max available performance state limits

2024-11-04T22:00:47Z

On some devices there are HW dependencies for shared frequency and voltage between devices. It will impact Energy Aware Scheduler (EAS) decision, where CPUs share the voltage & frequency domain with other CPUs or devices e.g. - Mid CPUs + Big CPU - Little CPU + L3 cache in DSU - some other device + Little CPUs Detailed explanation of one example: When the L3 cache frequency is increased, the affected Little CPUs might run at higher voltage and frequency. That higher voltage causes higher CPU power and thus more energy is used for running the tasks. This is important for background running tasks, which try to run on energy efficient CPUs. Therefore, add performance state limits which are applied for the device (in this case CPU). This is important on SoCs with HW dependencies mentioned above so that the Energy Aware Scheduler (EAS) does not use performance states outside the valid min-max range for energy calculation. Signed-off-by: Lukasz Luba Link: https://patch.msgid.link/20241030164126.1263793-2-lukasz.luba@arm.com Signed-off-by: Rafael J. Wysocki

arm64: Use SYSTEM_OFF2 PSCI call to power off for hibernate

2024-10-31T17:52:13Z

The PSCI v1.3 specification adds support for a SYSTEM_OFF2 function which is analogous to ACPI S4 state. This will allow hosting environments to determine that a guest is hibernated rather than just powered off, and handle that state appropriately on subsequent launches. Since commit 60c0d45a7f7a ("efi/arm64: use UEFI for system reset and poweroff") the EFI shutdown method is deliberately preferred over PSCI or other methods. So register a SYS_OFF_MODE_POWER_OFF handler which *only* handles the hibernation, leaving the original PSCI SYSTEM_OFF as a last resort via the legacy pm_power_off function pointer. The hibernation code already exports a system_entering_hibernation() function which is be used by the higher-priority handler to check for hibernation. That existing function just returns the value of a static boolean variable from hibernate.c, which was previously only set in the hibernation_platform_enter() code path. Set the same flag in the simpler code path around the call to kernel_power_off() too. An alternative way to hook SYSTEM_OFF2 into the hibernation code would be to register a platform_hibernation_ops structure with an ->enter() method which makes the new SYSTEM_OFF2 call. But that would have the unwanted side-effect of making hibernation take a completely different code path in hibernation_platform_enter(), invoking a lot of special dpm callbacks. Another option might be to add a new SYS_OFF_MODE_HIBERNATE mode, with fallback to SYS_OFF_MODE_POWER_OFF. Or to use the sys_off_data to indicate whether the power off is for hibernation. But this version works and is relatively simple. Signed-off-by: David Woodhouse Acked-by: Rafael J. Wysocki Acked-by: Catalin Marinas Link: https://lore.kernel.org/r/20241019172459.2241939-7-dwmw2@infradead.org Signed-off-by: Oliver Upton

[tree-wide] finally take no_llseek out

2024-09-27T15:18:43Z

no_llseek had been defined to NULL two years ago, in commit 868941b14441 ("fs: remove no_llseek") To quote that commit, At -rc1 we'll need do a mechanical removal of no_llseek - git grep -l -w no_llseek | grep -v porting.rst | while read i; do sed -i '/\/d' $i done would do it. Unfortunately, that hadn't been done. Linus, could you do that now, so that we could finally put that thing to rest? All instances are of the form .llseek = no_llseek, so it's obviously safe. Signed-off-by: Al Viro Signed-off-by: Linus Torvalds

PM: hibernate: Remove unused stub for saveable_highmem_page()

2024-09-10T18:11:40Z

When saveable_highmem_page() is unused, it prevents kernel builds with clang, `make W=1` and CONFIG_WERROR=y: kernel/power/snapshot.c:1369:21: error: unused function 'saveable_highmem_page' [-Werror,-Wunused-function] 1369 | static inline void *saveable_highmem_page(struct zone *z, unsigned long p) | ^~~~~~~~~~~~~~~~~~~~~ Fix this by removing unused stub. See also commit 6863f5643dd7 ("kbuild: allow Clang to find unused static inline functions for W=1 build"). Signed-off-by: Andy Shevchenko Link: https://patch.msgid.link/20240905184848.318978-1-andriy.shevchenko@linux.intel.com Signed-off-by: Rafael J. Wysocki

PM: sleep: Use sysfs_emit() and sysfs_emit_at() in "show" functions

2024-08-02T14:03:51Z

As Documentation/filesystems/sysfs.rst suggested, show() should only use sysfs_emit() or sysfs_emit_at() when formatting the value to be returned to user space. No functional change intended. Signed-off-by: Xueqin Luo Link: https://patch.msgid.link/20240801083156.2513508-3-luoxueqin@kylinos.cn [ rjw: Subject edit ] Signed-off-by: Rafael J. Wysocki

PM: hibernate: Use sysfs_emit() and sysfs_emit_at() in "show" functions

2024-08-02T14:03:51Z

As Documentation/filesystems/sysfs.rst suggested, show() should only use sysfs_emit() or sysfs_emit_at() when formatting the value to be returned to user space. No functional change intended. Signed-off-by: Xueqin Luo Link: https://patch.msgid.link/20240801083156.2513508-2-luoxueqin@kylinos.cn Signed-off-by: Rafael J. Wysocki

mm: remove the implementation of swap_free() and always use swap_free_nr()

2024-07-04T02:30:01Z

To streamline maintenance efforts, we propose removing the implementation of swap_free(). Instead, we can simply invoke swap_free_nr() with nr set to 1. swap_free_nr() is designed with a bitmap consisting of only one long, resulting in overhead that can be ignored for cases where nr equals 1. A prime candidate for leveraging swap_free_nr() lies within kernel/power/swap.c. Implementing this change facilitates the adoption of batch processing for hibernation. Link: https://lkml.kernel.org/r/20240529082824.150954-3-21cnbao@gmail.com Signed-off-by: Barry Song Suggested-by: "Huang, Ying" Reviewed-by: "Huang, Ying" Acked-by: Chris Li Reviewed-by: Ryan Roberts Cc: "Rafael J. Wysocki" Cc: Pavel Machek Cc: Len Brown Cc: Hugh Dickins Cc: Christoph Hellwig Cc: Andreas Larsson Cc: Baolin Wang Cc: Chuanhua Han Cc: David Hildenbrand Cc: "David S. Miller" Cc: Gao Xiang Cc: Johannes Weiner Cc: Kairui Song Cc: Khalid Aziz Cc: Matthew Wilcox (Oracle) Cc: Suren Baghdasaryan Cc: Yosry Ahmed Cc: Yu Zhao Cc: Zi Yan Signed-off-by: Andrew Morton

Merge tag 'vfs-6.10-rc2.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2024-05-27T15:09:12Z

Pull vfs fixes from Christian Brauner: - Fix io_uring based write-through after converting cifs to use the netfs library - Fix aio error handling when doing write-through via netfs library - Fix performance regression in iomap when used with non-large folio mappings - Fix signalfd error code - Remove obsolete comment in signalfd code - Fix async request indication in netfs_perform_write() by raising BDP_ASYNC when IOCB_NOWAIT is set - Yield swap device immediately to prevent spurious EBUSY errors - Don't cross a .backup mountpoint from backup volumes in afs to avoid infinite loops - Fix a race between umount and async request completion in 9p after 9p was converted to use the netfs library * tag 'vfs-6.10-rc2.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: netfs, 9p: Fix race between umount and async request completion afs: Don't cross .backup mountpoint from backup volume swap: yield device immediately netfs: Fix setting of BDP_ASYNC from iocb flags signalfd: drop an obsolete comment signalfd: fix error return code iomap: fault in smaller chunks for non-large folio mappings filemap: add helper mapping_max_folio_size() netfs: Fix AIO error handling when doing write-through netfs: Fix io_uring based write-through

swap: yield device immediately

2024-05-24T11:34:08Z

Otherwise we can cause spurious EBUSY issues when trying to mount the rootfs later on. Link: https://bugzilla.kernel.org/show_bug.cgi?id=218845 Reported-by: Petri Kaukasoina Signed-off-by: Christian Brauner