kernel/include/asm-generic, branch linux-6.17.y

rqspinlock: Enclose lock/unlock within lock entry acquisitions

2025-12-18T13:00:03Z

[ Upstream commit beb7021a6003d9c6a463fffca0d6311efb8e0e66 ] Ritesh reported that timeouts occurred frequently for rqspinlock despite reentrancy on the same lock on the same CPU in [0]. This patch closes one of the races leading to this behavior, and reduces the frequency of timeouts. We currently have a tiny window between the fast-path cmpxchg and the grabbing of the lock entry where an NMI could land, attempt the same lock that was just acquired, and end up timing out. This is not ideal. Instead, move the lock entry acquisition from the fast path to before the cmpxchg, and remove the grabbing of the lock entry in the slow path, assuming it was already taken by the fast path. The TAS fallback is invoked directly without being preceded by the typical fast path, therefore we must continue to grab the deadlock detection entry in that case. Case on lock leading to missed AA: cmpxchg lock A ... rqspinlock acquisition of A ... timeout grab_held_lock_entry(A) There is a similar case when unlocking the lock. If the NMI lands between the WRITE_ONCE and smp_store_release, it is possible that we end up in a situation where the NMI fails to diagnose the AA condition, leading to a timeout. Case on unlock leading to missed AA: WRITE_ONCE(rqh->locks[rqh->cnt - 1], NULL) ... rqspinlock acquisition of A ... timeout smp_store_release(A->locked, 0) The patch changes the order on unlock to smp_store_release() succeeded by WRITE_ONCE() of NULL. This avoids the missed AA detection described above, but may lead to a false positive if the NMI lands between these two statements, which is acceptable (and preferred over a timeout). The original intention of the reverse order on unlock was to prevent the following possible misdiagnosis of an ABBA scenario: grab entry A lock A grab entry B lock B unlock B smp_store_release(B->locked, 0) grab entry B lock B grab entry A lock A ! WRITE_ONCE(rqh->locks[rqh->cnt - 1], NULL) If the store release were is after the WRITE_ONCE, the other CPU would not observe B in the table of the CPU unlocking the lock B. However, since the threads are obviously participating in an ABBA deadlock, it is no longer appealing to use the order above since it may lead to a 250 ms timeout due to missed AA detection. [0]: https://lore.kernel.org/bpf/CAH6OuBTjG+N=+GGwcpOUbeDN563oz4iVcU3rbse68egp9wj9_A@mail.gmail.com Fixes: 0d80e7f951be ("rqspinlock: Choose trylock fallback for NMI waiters") Reported-by: Ritesh Oedayrajsingh Varma Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20251128232802.1031906-2-memxor@gmail.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin

mshv: Fix deposit memory in MSHV_ROOT_HVCALL

2025-12-18T12:59:43Z

[ Upstream commit 4cc1aa469cd6b714adc958547a4866247bfd60a9 ] When the MSHV_ROOT_HVCALL ioctl is executing a hypercall, and gets HV_STATUS_INSUFFICIENT_MEMORY, it deposits memory and then returns -EAGAIN to userspace. The expectation is that the VMM will retry. However, some VMM code in the wild doesn't do this and simply fails. Rather than force the VMM to retry, change the ioctl to deposit memory on demand and immediately retry the hypercall as is done with all the other hypercall helper functions. In addition to making the ioctl easier to use, removing the need for multiple syscalls improves performance. There is a complication: unlike the other hypercall helper functions, in MSHV_ROOT_HVCALL the input is opaque to the kernel. This is problematic for rep hypercalls, because the next part of the input list can't be copied on each loop after depositing pages (this was the original reason for returning -EAGAIN in this case). Introduce hv_do_rep_hypercall_ex(), which adds a 'rep_start' parameter. This solves the issue, allowing the deposit loop in MSHV_ROOT_HVCALL to restart a rep hypercall after depositing pages partway through. Fixes: 621191d709b1 ("Drivers: hv: Introduce mshv_root module to expose /dev/mshv to VMMs") Signed-off-by: Nuno Das Neves Reviewed-by: Michael Kelley Signed-off-by: Wei Liu Signed-off-by: Sasha Levin

kbuild: align modinfo section for Secureboot Authenticode EDK2 compat

2025-11-13T20:36:43Z

commit d50f21091358b2b29dc06c2061106cdb0f030d03 upstream. Previously linker scripts would always generate vmlinuz that has sections aligned. And thus padded (correct Authenticode calculation) and unpadded calculation would be same. As in https://github.com/rhboot/pesign userspace tool would produce the same authenticode digest for both of the following commands: pesign --padding --hash --in ./arch/x86_64/boot/bzImage pesign --nopadding --hash --in ./arch/x86_64/boot/bzImage The commit 3e86e4d74c04 ("kbuild: keep .modinfo section in vmlinux.unstripped") added .modinfo section of variable length. Depending on kernel configuration it may or may not be aligned. All userspace signing tooling correctly pads such section to calculation spec compliant authenticode digest. However, if bzImage is not further processed and is attempted to be loaded directly by EDK2 firmware, it calculates unpadded Authenticode digest and fails to correct accept/reject such kernel builds even when propoer Authenticode values are enrolled in db/dbx. One can say EDK2 requires aligned/padded kernels in Secureboot. Thus add ALIGN(8) to the .modinfo section, to esure kernels irrespective of modinfo contents can be loaded by all existing EDK2 firmware builds. Fixes: 3e86e4d74c04 ("kbuild: keep .modinfo section in vmlinux.unstripped") Cc: stable@vger.kernel.org Signed-off-by: Dimitri John Ledkov Link: https://patch.msgid.link/20251026202100.679989-1-dimitri.ledkov@surgut.co.uk Signed-off-by: Nathan Chancellor Signed-off-by: Greg Kroah-Hartman

kbuild: keep .modinfo section in vmlinux.unstripped

2025-10-19T14:37:15Z

[ Upstream commit 3e86e4d74c0490e5fc5a7f8de8f29e7579c9ffe5 ] Keep the .modinfo section during linking, but strip it from the final vmlinux. Adjust scripts/mksysmap to exclude modinfo symbols from kallsyms. This change will allow the next commit to extract the .modinfo section from the vmlinux.unstripped intermediate. Signed-off-by: Masahiro Yamada Signed-off-by: Alexey Gladkov Reviewed-by: Nicolas Schier Link: https://patch.msgid.link/aaf67c07447215463300fccaa758904bac42f992.1758182101.git.legion@kernel.org Signed-off-by: Nathan Chancellor Stable-dep-of: 8ec3af916fe3 ("kbuild: Add '.rel.*' strip pattern for vmlinux") Signed-off-by: Sasha Levin

asm-generic/io.h: Skip trace helpers if rwmmio events are disabled

2025-10-19T14:37:01Z

commit 8327bd4fcb6c1dab01ce5c6ff00b42496836dcd2 upstream. With `CONFIG_TRACE_MMIO_ACCESS=y`, the `{read,write}{b,w,l,q}{_relaxed}()` mmio accessors unconditionally call `log_{post_}{read,write}_mmio()` helpers, which in turn call the ftrace ops for `rwmmio` trace events This adds a performance penalty per mmio accessor call, even when `rwmmio` events are disabled at runtime (~80% overhead on local measurement). Guard these with `tracepoint_enabled()`. Signed-off-by: Varad Gautam Fixes: 210031971cdd ("asm-generic/io: Add logging support for MMIO accessors") Cc: stable@vger.kernel.org Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

once: fix race by moving DO_ONCE to separate section

2025-10-15T10:03:37Z

[ Upstream commit edcc8a38b5ac1a3dbd05e113a38a25b937ebefe5 ] The commit c2c60ea37e5b ("once: use __section(".data.once")") moved DO_ONCE's ___done variable to .data.once section, which conflicts with DO_ONCE_LITE() that also uses the same section. This creates a race condition when clear_warn_once is used: Thread 1 (DO_ONCE) Thread 2 (DO_ONCE) __do_once_start read ___done (false) acquire once_lock execute func __do_once_done write ___done (true) __do_once_start release once_lock // Thread 3 clear_warn_once reset ___done read ___done (false) acquire once_lock execute func schedule once_work __do_once_done once_deferred: OK write ___done (true) static_branch_disable release once_lock schedule once_work once_deferred: BUG_ON(!static_key_enabled) DO_ONCE_LITE() in once_lite.h is used by WARN_ON_ONCE() and other warning macros. Keep its ___done flag in the .data..once section and allow resetting by clear_warn_once, as originally intended. In contrast, DO_ONCE() is used for functions like get_random_once() and relies on its ___done flag for internal synchronization. We should not reset DO_ONCE() by clear_warn_once. Fix it by isolating DO_ONCE's ___done into a separate .data..do_once section, shielding it from clear_warn_once. Fixes: c2c60ea37e5b ("once: use __section(".data.once")") Reported-by: Hulk Robot Signed-off-by: Qi Xi Signed-off-by: Arnd Bergmann Signed-off-by: Sasha Levin

Merge tag 'trace-deferred-unwind-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2025-08-01T16:46:24Z

Pull initial deferred unwind infrastructure from Steven Rostedt: "This is the core infrastructure for the deferred unwinder that is required for sframes[1]. Several other patch series are based on this work although those patch series are not dependent on each other. In order to simplify the development, having this core series upstream will allow the other series to be worked on in parallel. The other series are: - The two patches to implement x86 support [2] [3] - The s390 work [4] - The perf work [5] - The ftrace work [6] - The sframe work [7] And more is on the way. The core infrastructure adds the following in kernel APIs: - int unwind_user_faultable(struct unwind_stacktrace *trace); Performs a user space stack trace that may fault user pages in. - int unwind_deferred_init(struct unwind_work *work, unwind_callback_t func); Allows a tracer to register with the unwind deferred infrastructure. - int unwind_deferred_request(struct unwind_work *work, u64 *cookie); Used when a tracer request a deferred trace. Can be called from interrupt or NMI context. - void unwind_deferred_cancel(struct unwind_work *work); Called by a tracer to unregister from the deferred unwind infrastructure. - void unwind_deferred_task_exit(struct task_struct *task); Called by task exit code to flush any pending unwind requests. - void unwind_task_init(struct task_struct *task); Called by do_fork() to initialize the task struct for the deferred unwinder. - void unwind_task_free(struct task_struct *task); Called by do_exit() to free up any resources used by the deferred unwinder. None of the above is actually compiled unless an architecture enables it, which none currently do" Link: https://sourceware.org/binutils/wiki/sframe [1] Link: https://lore.kernel.org/linux-trace-kernel/20250717004958.260781923@kernel.org/ [2] Link: https://lore.kernel.org/linux-trace-kernel/20250717004958.432327787@kernel.org/ [3] Link: https://lore.kernel.org/linux-trace-kernel/20250710163522.3195293-1-jremus@linux.ibm.com/ [4] Link: https://lore.kernel.org/linux-trace-kernel/20250718164119.089692174@kernel.org/ [5] Link: https://lore.kernel.org/linux-trace-kernel/20250424192612.505622711@goodmis.org/ [6] Link: https://lore.kernel.org/linux-trace-kernel/20250717012848.927473176@kernel.org/ [7] * tag 'trace-deferred-unwind-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: unwind: Finish up unwind when a task exits unwind deferred: Use SRCU unwind_deferred_task_work() unwind: Add USED bit to only have one conditional on way back to user space unwind deferred: Add unwind_completed mask to stop spurious callbacks unwind deferred: Use bitmask to determine which callbacks to call unwind_user/deferred: Make unwind deferral requests NMI-safe unwind_user/deferred: Add deferred unwinding interface unwind_user/deferred: Add unwind cache unwind_user/deferred: Add unwind_user_faultable() unwind_user: Add user space unwinding API with frame pointer support

Merge tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-07-31T21:57:54Z

Pull MM updates from Andrew Morton: "As usual, many cleanups. The below blurbiage describes 42 patchsets. 21 of those are partially or fully cleanup work. "cleans up", "cleanup", "maintainability", "rationalizes", etc. I never knew the MM code was so dirty. "mm: ksm: prevent KSM from breaking merging of new VMAs" (Lorenzo Stoakes) addresses an issue with KSM's PR_SET_MEMORY_MERGE mode: newly mapped VMAs were not eligible for merging with existing adjacent VMAs. "mm/damon: introduce DAMON_STAT for simple and practical access monitoring" (SeongJae Park) adds a new kernel module which simplifies the setup and usage of DAMON in production environments. "stop passing a writeback_control to swap/shmem writeout" (Christoph Hellwig) is a cleanup to the writeback code which removes a couple of pointers from struct writeback_control. "drivers/base/node.c: optimization and cleanups" (Donet Tom) contains largely uncorrelated cleanups to the NUMA node setup and management code. "mm: userfaultfd: assorted fixes and cleanups" (Tal Zussman) does some maintenance work on the userfaultfd code. "Readahead tweaks for larger folios" (Ryan Roberts) implements some tuneups for pagecache readahead when it is reading into order>0 folios. "selftests/mm: Tweaks to the cow test" (Mark Brown) provides some cleanups and consistency improvements to the selftests code. "Optimize mremap() for large folios" (Dev Jain) does that. A 37% reduction in execution time was measured in a memset+mremap+munmap microbenchmark. "Remove zero_user()" (Matthew Wilcox) expunges zero_user() in favor of the more modern memzero_page(). "mm/huge_memory: vmf_insert_folio_*() and vmf_insert_pfn_pud() fixes" (David Hildenbrand) addresses some warts which David noticed in the huge page code. These were not known to be causing any issues at this time. "mm/damon: use alloc_migrate_target() for DAMOS_MIGRATE_{HOT,COLD" (SeongJae Park) provides some cleanup and consolidation work in DAMON. "use vm_flags_t consistently" (Lorenzo Stoakes) uses vm_flags_t in places where we were inappropriately using other types. "mm/memfd: Reserve hugetlb folios before allocation" (Vivek Kasireddy) increases the reliability of large page allocation in the memfd code. "mm: Remove pXX_devmap page table bit and pfn_t type" (Alistair Popple) removes several now-unneeded PFN_* flags. "mm/damon: decouple sysfs from core" (SeongJae Park) implememnts some cleanup and maintainability work in the DAMON sysfs layer. "madvise cleanup" (Lorenzo Stoakes) does quite a lot of cleanup/maintenance work in the madvise() code. "madvise anon_name cleanups" (Vlastimil Babka) provides additional cleanups on top or Lorenzo's effort. "Implement numa node notifier" (Oscar Salvador) creates a standalone notifier for NUMA node memory state changes. Previously these were lumped under the more general memory on/offline notifier. "Make MIGRATE_ISOLATE a standalone bit" (Zi Yan) cleans up the pageblock isolation code and fixes a potential issue which doesn't seem to cause any problems in practice. "selftests/damon: add python and drgn based DAMON sysfs functionality tests" (SeongJae Park) adds additional drgn- and python-based DAMON selftests which are more comprehensive than the existing selftest suite. "Misc rework on hugetlb faulting path" (Oscar Salvador) fixes a rather obscure deadlock in the hugetlb fault code and follows that fix with a series of cleanups. "cma: factor out allocation logic from __cma_declare_contiguous_nid" (Mike Rapoport) rationalizes and cleans up the highmem-specific code in the CMA allocator. "mm/migration: rework movable_ops page migration (part 1)" (David Hildenbrand) provides cleanups and future-preparedness to the migration code. "mm/damon: add trace events for auto-tuned monitoring intervals and DAMOS quota" (SeongJae Park) adds some tracepoints to some DAMON auto-tuning code. "mm/damon: fix misc bugs in DAMON modules" (SeongJae Park) does that. "mm/damon: misc cleanups" (SeongJae Park) also does what it claims. "mm: folio_pte_batch() improvements" (David Hildenbrand) cleans up the large folio PTE batching code. "mm/damon/vaddr: Allow interleaving in migrate_{hot,cold} actions" (SeongJae Park) facilitates dynamic alteration of DAMON's inter-node allocation policy. "Remove unmap_and_put_page()" (Vishal Moola) provides a couple of page->folio conversions. "mm: per-node proactive reclaim" (Davidlohr Bueso) implements a per-node control of proactive reclaim - beyond the current memcg-based implementation. "mm/damon: remove damon_callback" (SeongJae Park) replaces the damon_callback interface with a more general and powerful damon_call()+damos_walk() interface. "mm/mremap: permit mremap() move of multiple VMAs" (Lorenzo Stoakes) implements a number of mremap cleanups (of course) in preparation for adding new mremap() functionality: newly permit the remapping of multiple VMAs when the user is specifying MREMAP_FIXED. It still excludes some specialized situations where this cannot be performed reliably. "drop hugetlb_free_pgd_range()" (Anthony Yznaga) switches some sparc hugetlb code over to the generic version and removes the thus-unneeded hugetlb_free_pgd_range(). "mm/damon/sysfs: support periodic and automated stats update" (SeongJae Park) augments the present userspace-requested update of DAMON sysfs monitoring files. Automatic update is now provided, along with a tunable to control the update interval. "Some randome fixes and cleanups to swapfile" (Kemeng Shi) does what is claims. "mm: introduce snapshot_page" (Luiz Capitulino and David Hildenbrand) provides (and uses) a means by which debug-style functions can grab a copy of a pageframe and inspect it locklessly without tripping over the races inherent in operating on the live pageframe directly. "use per-vma locks for /proc/pid/maps reads" (Suren Baghdasaryan) addresses the large contention issues which can be triggered by reads from that procfs file. Latencies are reduced by more than half in some situations. The series also introduces several new selftests for the /proc/pid/maps interface. "__folio_split() clean up" (Zi Yan) cleans up __folio_split()! "Optimize mprotect() for large folios" (Dev Jain) provides some quite large (>3x) speedups to mprotect() when dealing with large folios. "selftests/mm: reuse FORCE_READ to replace "asm volatile("" : "+r" (XXX));" and some cleanup" (wang lian) does some cleanup work in the selftests code. "tools/testing: expand mremap testing" (Lorenzo Stoakes) extends the mremap() selftest in several ways, including adding more checking of Lorenzo's recently added "permit mremap() move of multiple VMAs" feature. "selftests/damon/sysfs.py: test all parameters" (SeongJae Park) extends the DAMON sysfs interface selftest so that it tests all possible user-requested parameters. Rather than the present minimal subset" * tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (370 commits) MAINTAINERS: add missing headers to mempory policy & migration section MAINTAINERS: add missing file to cgroup section MAINTAINERS: add MM MISC section, add missing files to MISC and CORE MAINTAINERS: add missing zsmalloc file MAINTAINERS: add missing files to page alloc section MAINTAINERS: add missing shrinker files MAINTAINERS: move memremap.[ch] to hotplug section MAINTAINERS: add missing mm_slot.h file THP section MAINTAINERS: add missing interval_tree.c to memory mapping section MAINTAINERS: add missing percpu-internal.h file to per-cpu section mm/page_alloc: remove trace_mm_alloc_contig_migrate_range_info() selftests/damon: introduce _common.sh to host shared function selftests/damon/sysfs.py: test runtime reduction of DAMON parameters selftests/damon/sysfs.py: test non-default parameters runtime commit selftests/damon/sysfs.py: generalize DAMON context commit assertion selftests/damon/sysfs.py: generalize monitoring attributes commit assertion selftests/damon/sysfs.py: generalize DAMOS schemes commit assertion selftests/damon/sysfs.py: test DAMOS filters commitment selftests/damon/sysfs.py: generalize DAMOS scheme commit assertion selftests/damon/sysfs.py: test DAMOS destinations commitment ...

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

2025-07-31T00:14:01Z

Pull kvm updates from Paolo Bonzini: "ARM: - Host driver for GICv5, the next generation interrupt controller for arm64, including support for interrupt routing, MSIs, interrupt translation and wired interrupts - Use FEAT_GCIE_LEGACY on GICv5 systems to virtualize GICv3 VMs on GICv5 hardware, leveraging the legacy VGIC interface - Userspace control of the 'nASSGIcap' GICv3 feature, allowing userspace to disable support for SGIs w/o an active state on hardware that previously advertised it unconditionally - Map supporting endpoints with cacheable memory attributes on systems with FEAT_S2FWB and DIC where KVM no longer needs to perform cache maintenance on the address range - Nested support for FEAT_RAS and FEAT_DoubleFault2, allowing the guest hypervisor to inject external aborts into an L2 VM and take traps of masked external aborts to the hypervisor - Convert more system register sanitization to the config-driven implementation - Fixes to the visibility of EL2 registers, namely making VGICv3 system registers accessible through the VGIC device instead of the ONE_REG vCPU ioctls - Various cleanups and minor fixes LoongArch: - Add stat information for in-kernel irqchip - Add tracepoints for CPUCFG and CSR emulation exits - Enhance in-kernel irqchip emulation - Various cleanups RISC-V: - Enable ring-based dirty memory tracking - Improve perf kvm stat to report interrupt events - Delegate illegal instruction trap to VS-mode - MMU improvements related to upcoming nested virtualization s390x - Fixes x86: - Add CONFIG_KVM_IOAPIC for x86 to allow disabling support for I/O APIC, PIC, and PIT emulation at compile time - Share device posted IRQ code between SVM and VMX and harden it against bugs and runtime errors - Use vcpu_idx, not vcpu_id, for GA log tag/metadata, to make lookups O(1) instead of O(n) - For MMIO stale data mitigation, track whether or not a vCPU has access to (host) MMIO based on whether the page tables have MMIO pfns mapped; using VFIO is prone to false negatives - Rework the MSR interception code so that the SVM and VMX APIs are more or less identical - Recalculate all MSR intercepts from scratch on MSR filter changes, instead of maintaining shadow bitmaps - Advertise support for LKGS (Load Kernel GS base), a new instruction that's loosely related to FRED, but is supported and enumerated independently - Fix a user-triggerable WARN that syzkaller found by setting the vCPU in INIT_RECEIVED state (aka wait-for-SIPI), and then putting the vCPU into VMX Root Mode (post-VMXON). Trying to detect every possible path leading to architecturally forbidden states is hard and even risks breaking userspace (if it goes from valid to valid state but passes through invalid states), so just wait until KVM_RUN to detect that the vCPU state isn't allowed - Add KVM_X86_DISABLE_EXITS_APERFMPERF to allow disabling interception of APERF/MPERF reads, so that a "properly" configured VM can access APERF/MPERF. This has many caveats (APERF/MPERF cannot be zeroed on vCPU creation or saved/restored on suspend and resume, or preserved over thread migration let alone VM migration) but can be useful whenever you're interested in letting Linux guests see the effective physical CPU frequency in /proc/cpuinfo - Reject KVM_SET_TSC_KHZ for vm file descriptors if vCPUs have been created, as there's no known use case for changing the default frequency for other VM types and it goes counter to the very reason why the ioctl was added to the vm file descriptor. And also, there would be no way to make it work for confidential VMs with a "secure" TSC, so kill two birds with one stone - Dynamically allocation the shadow MMU's hashed page list, and defer allocating the hashed list until it's actually needed (the TDP MMU doesn't use the list) - Extract many of KVM's helpers for accessing architectural local APIC state to common x86 so that they can be shared by guest-side code for Secure AVIC - Various cleanups and fixes x86 (Intel): - Preserve the host's DEBUGCTL.FREEZE_IN_SMM when running the guest. Failure to honor FREEZE_IN_SMM can leak host state into guests - Explicitly check vmcs12.GUEST_DEBUGCTL on nested VM-Enter to prevent L1 from running L2 with features that KVM doesn't support, e.g. BTF x86 (AMD): - WARN and reject loading kvm-amd.ko instead of panicking the kernel if the nested SVM MSRPM offsets tracker can't handle an MSR (which is pretty much a static condition and therefore should never happen, but still) - Fix a variety of flaws and bugs in the AVIC device posted IRQ code - Inhibit AVIC if a vCPU's ID is too big (relative to what hardware supports) instead of rejecting vCPU creation - Extend enable_ipiv module param support to SVM, by simply leaving IsRunning clear in the vCPU's physical ID table entry - Disable IPI virtualization, via enable_ipiv, if the CPU is affected by erratum #1235, to allow (safely) enabling AVIC on such CPUs - Request GA Log interrupts if and only if the target vCPU is blocking, i.e. only if KVM needs a notification in order to wake the vCPU - Intercept SPEC_CTRL on AMD if the MSR shouldn't exist according to the vCPU's CPUID model - Accept any SNP policy that is accepted by the firmware with respect to SMT and single-socket restrictions. An incompatible policy doesn't put the kernel at risk in any way, so there's no reason for KVM to care - Drop a superfluous WBINVD (on all CPUs!) when destroying a VM and use WBNOINVD instead of WBINVD when possible for SEV cache maintenance - When reclaiming memory from an SEV guest, only do cache flushes on CPUs that have ever run a vCPU for the guest, i.e. don't flush the caches for CPUs that can't possibly have cache lines with dirty, encrypted data Generic: - Rework irqbypass to track/match producers and consumers via an xarray instead of a linked list. Using a linked list leads to O(n^2) insertion times, which is hugely problematic for use cases that create large numbers of VMs. Such use cases typically don't actually use irqbypass, but eliminating the pointless registration is a future problem to solve as it likely requires new uAPI - Track irqbypass's "token" as "struct eventfd_ctx *" instead of a "void *", to avoid making a simple concept unnecessarily difficult to understand - Decouple device posted IRQs from VFIO device assignment, as binding a VM to a VFIO group is not a requirement for enabling device posted IRQs - Clean up and document/comment the irqfd assignment code - Disallow binding multiple irqfds to an eventfd with a priority waiter, i.e. ensure an eventfd is bound to at most one irqfd through the entire host, and add a selftest to verify eventfd:irqfd bindings are globally unique - Add a tracepoint for KVM_SET_MEMORY_ATTRIBUTES to help debug issues related to private <=> shared memory conversions - Drop guest_memfd's .getattr() implementation as the VFS layer will call generic_fillattr() if inode_operations.getattr is NULL - Fix issues with dirty ring harvesting where KVM doesn't bound the processing of entries in any way, which allows userspace to keep KVM in a tight loop indefinitely - Kill off kvm_arch_{start,end}_assignment() and x86's associated tracking, now that KVM no longer uses assigned_device_count as a heuristic for either irqbypass usage or MDS mitigation Selftests: - Fix a comment typo - Verify KVM is loaded when getting any KVM module param so that attempting to run a selftest without kvm.ko loaded results in a SKIP message about KVM not being loaded/enabled (versus some random parameter not existing) - Skip tests that hit EACCES when attempting to access a file, and print a "Root required?" help message. In most cases, the test just needs to be run with elevated permissions" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (340 commits) Documentation: KVM: Use unordered list for pre-init VGIC registers RISC-V: KVM: Avoid re-acquiring memslot in kvm_riscv_gstage_map() RISC-V: KVM: Use find_vma_intersection() to search for intersecting VMAs RISC-V: perf/kvm: Add reporting of interrupt events RISC-V: KVM: Enable ring-based dirty memory tracking RISC-V: KVM: Fix inclusion of Smnpm in the guest ISA bitmap RISC-V: KVM: Delegate illegal instruction fault to VS mode RISC-V: KVM: Pass VMID as parameter to kvm_riscv_hfence_xyz() APIs RISC-V: KVM: Factor-out g-stage page table management RISC-V: KVM: Add vmid field to struct kvm_riscv_hfence RISC-V: KVM: Introduce struct kvm_gstage_mapping RISC-V: KVM: Factor-out MMU related declarations into separate headers RISC-V: KVM: Use ncsr_xyz() in kvm_riscv_vcpu_trap_redirect() RISC-V: KVM: Implement kvm_arch_flush_remote_tlbs_range() RISC-V: KVM: Don't flush TLB when PTE is unchanged RISC-V: KVM: Replace KVM_REQ_HFENCE_GVMA_VMID_ALL with KVM_REQ_TLB_FLUSH RISC-V: KVM: Rename and move kvm_riscv_local_tlb_sanitize() RISC-V: KVM: Drop the return value of kvm_riscv_vcpu_aia_init() RISC-V: KVM: Check kvm_riscv_vcpu_alloc_vector_context() return value KVM: arm64: selftests: Add FEAT_RAS EL2 registers to get-reg-list ...

Merge tag 'ftrace-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2025-07-30T23:04:10Z

Pull ftrace updates from Steven Rostedt: - Keep track of when fgraph_ops are registered or not Keep accounting of when fgraph_ops are registered as if a fgraph_ops is registered twice it can mess up the accounting and it will not work as expected later. Trigger a warning if something registers it twice as to catch bugs before they are found by things just not working as expected. - Make DYNAMIC_FTRACE always enabled for architectures that support it As static ftrace (where all functions are always traced) is very expensive and only exists to help architectures support ftrace, do not make it an option. As soon as an architecture supports DYNAMIC_FTRACE make it use it. This simplifies the code. - Remove redundant config HAVE_FTRACE_MCOUNT_RECORD The CONFIG_HAVE_FTRACE_MCOUNT was added to help simplify the DYNAMIC_FTRACE work, but now every architecture that implements DYNAMIC_FTRACE also has HAVE_FTRACE_MCOUNT set too, making it redundant with the HAVE_DYNAMIC_FTRACE. - Make pid_ptr string size match the comment In print_graph_proc() the pid_ptr string is of size 11, but the comment says /* sign + log10(MAX_INT) + '\0' */ which is actually 12. * tag 'ftrace-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing: Remove redundant config HAVE_FTRACE_MCOUNT_RECORD ftrace: Make DYNAMIC_FTRACE always enabled for architectures that support it fgraph: Keep track of when fgraph_ops are registered or not fgraph: Make pid_str size match the comment