January 2025 - Linux-kselftest-mirror

[RFC PATCH 00/39] 1G page support for guest_memfd

by Ackerley Tng

Hello, This patchset is our exploration of how to support 1G pages in guest_memfd, and how the pages will be used in Confidential VMs. The patchset covers: + How to get 1G pages + Allowing mmap() of guest_memfd to userspace so that both private and shared memory can use the same physical pages + Splitting and reconstructing pages to support conversions and mmap() + How the VM, userspace and guest_memfd interact to support conversions + Selftests to test all the above + Selftests also demonstrate the conversion flow between VM, userspace and guest_memfd. Why 1G pages in guest memfd? Bring guest_memfd to performance and memory savings parity with VMs that are backed by HugeTLBfs. + Performance is improved with 1G pages by more TLB hits and faster page walks on TLB misses. + Memory savings from 1G pages comes from HugeTLB Vmemmap Optimization (HVO). Options for 1G page support: 1. HugeTLB 2. Contiguous Memory Allocator (CMA) 3. Other suggestions are welcome! Comparison between options: 1. HugeTLB + Refactor HugeTLB to separate allocator from the rest of HugeTLB + Pro: Graceful transition for VMs backed with HugeTLB to guest_memfd + Near term: Allows co-tenancy of HugeTLB and guest_memfd backed VMs + Pro: Can provide iterative steps toward new future allocator + Unexplored: Managing userspace-visible changes + e.g. HugeTLB's free_hugepages will decrease if HugeTLB is used, but not when future allocator is used 2. CMA + Port some HugeTLB features to be applied on CMA + Pro: Clean slate What would refactoring HugeTLB involve? (Some refactoring was done in this RFC, more can be done.) 1. Broadly involves separating the HugeTLB allocator from the rest of HugeTLB + Brings more modularity to HugeTLB + No functionality change intended + Likely step towards HugeTLB's integration into core-mm 2. guest_memfd will use just the allocator component of HugeTLB, not including the complex parts of HugeTLB like + Userspace reservations (resv_map) + Shared PMD mappings + Special page walkers What features would need to be ported to CMA? + Improved allocation guarantees + Per NUMA node pool of huge pages + Subpools per guest_memfd + Memory savings + Something like HugeTLB Vmemmap Optimization + Configuration/reporting features + Configuration of number of pages available (and per NUMA node) at and after host boot + Reporting of memory usage/availability statistics at runtime HugeTLB was picked as the source of 1G pages for this RFC because it allows a graceful transition, and retains memory savings from HVO. To illustrate this, if a host machine uses HugeTLBfs to back VMs, and a confidential VM were to be scheduled on that host, some HugeTLBfs pages would have to be given up and returned to CMA for guest_memfd pages to be rebuilt from that memory. This requires memory to be reserved for HVO to be removed and reapplied on the new guest_memfd memory. This not only slows down memory allocation but also trims the benefits of HVO. Memory would have to be reserved on the host to facilitate these transitions. Improving how guest_memfd uses the allocator in a future revision of this RFC: To provide an easier transition away from HugeTLB, guest_memfd's use of HugeTLB should be limited to these allocator functions: + reserve(node, page_size, num_pages) => opaque handle + Used when a guest_memfd inode is created to reserve memory from backend allocator + allocate(handle, mempolicy, page_size) => folio + To allocate a folio from guest_memfd's reservation + split(handle, folio, target_page_size) => void + To take a huge folio, and split it to smaller folios, restore to filemap + reconstruct(handle, first_folio, nr_pages) => void + To take a folio, and reconstruct a huge folio out of nr_pages from the first_folio + free(handle, folio) => void + To return folio to guest_memfd's reservation + error(handle, folio) => void + To handle memory errors + unreserve(handle) => void + To return guest_memfd's reservation to allocator backend Userspace should only provide a page size when creating a guest_memfd and should not have to specify HugeTLB. Overview of patches: + Patches 01-12 + Many small changes to HugeTLB, mostly to separate HugeTLBfs concepts from HugeTLB, and to expose HugeTLB functions. + Patches 13-16 + Letting guest_memfd use HugeTLB + Creation of each guest_memfd reserves pages from HugeTLB's global hstate and puts it into the guest_memfd inode's subpool + Each folio allocation takes a page from the guest_memfd inode's subpool + Patches 17-21 + Selftests for new HugeTLB features in guest_memfd + Patches 22-24 + More small changes on the HugeTLB side to expose functions needed by guest_memfd + Patch 25: + Uses the newly available functions from patches 22-24 to split HugeTLB pages. In this patch, HugeTLB folios are always split to 4K before any usage, private or shared. + Patches 26-28 + Allow mmap() in guest_memfd and faulting in shared pages + Patch 29 + Enables conversion between private/shared pages + Patch 30 + Required to zero folios after conversions to avoid leaking initialized kernel memory + Patch 31-38 + Add selftests to test mapping pages to userspace, guest/host memory sharing and update conversions tests + Patch 33 illustrates the conversion flow between VM/userspace/guest_memfd + Patch 39 + Dynamically split and reconstruct HugeTLB pages instead of always splitting before use. All earlier selftests are expected to still pass. TODOs: + Add logic to wait for safe_refcount [1] + Look into lazy splitting/reconstruction of pages + Currently, when the KVM_SET_MEMORY_ATTRIBUTES is invoked, not only is the mem_attr_array and faultability updated, the pages in the requested range are also split/reconstructed as necessary. We want to look into delaying splitting/reconstruction to fault time. + Solve race between folios being faulted in and being truncated + When running private_mem_conversions_test with more than 1 vCPU, a folio getting truncated may get faulted in by another process, causing elevated mapcounts when the folio is freed (VM_BUG_ON_FOLIO). + Add intermediate splits (1G should first split to 2M and not split directly to 4K) + Use guest's lock instead of hugetlb_lock + Use multi-index xarray/replace xarray with some other data struct for faultability flag + Refactor HugeTLB better, present generic allocator interface Please let us know your thoughts on: + HugeTLB as the choice of transitional allocator backend + Refactoring HugeTLB to provide generic allocator interface + Shared/private conversion flow + Requiring user to request kernel to unmap pages from userspace using madvise(MADV_DONTNEED) + Failing conversion on elevated mapcounts/pincounts/refcounts + Process of splitting/reconstructing page + Anything else! [1] https://lore.kernel.org/all/20240829-guest-memfd-lib-v2-0-b9afc1ff3656@quic… Ackerley Tng (37): mm: hugetlb: Simplify logic in dequeue_hugetlb_folio_vma() mm: hugetlb: Refactor vma_has_reserves() to should_use_hstate_resv() mm: hugetlb: Remove unnecessary check for avoid_reserve mm: mempolicy: Refactor out policy_node_nodemask() mm: hugetlb: Refactor alloc_buddy_hugetlb_folio_with_mpol() to interpret mempolicy instead of vma mm: hugetlb: Refactor dequeue_hugetlb_folio_vma() to use mpol mm: hugetlb: Refactor out hugetlb_alloc_folio mm: truncate: Expose preparation steps for truncate_inode_pages_final mm: hugetlb: Expose hugetlb_subpool_{get,put}_pages() mm: hugetlb: Add option to create new subpool without using surplus mm: hugetlb: Expose hugetlb_acct_memory() mm: hugetlb: Move and expose hugetlb_zero_partial_page() KVM: guest_memfd: Make guest mem use guest mem inodes instead of anonymous inodes KVM: guest_memfd: hugetlb: initialization and cleanup KVM: guest_memfd: hugetlb: allocate and truncate from hugetlb KVM: guest_memfd: Add page alignment check for hugetlb guest_memfd KVM: selftests: Add basic selftests for hugetlb-backed guest_memfd KVM: selftests: Support various types of backing sources for private memory KVM: selftests: Update test for various private memory backing source types KVM: selftests: Add private_mem_conversions_test.sh KVM: selftests: Test that guest_memfd usage is reported via hugetlb mm: hugetlb: Expose vmemmap optimization functions mm: hugetlb: Expose HugeTLB functions for promoting/demoting pages mm: hugetlb: Add functions to add/move/remove from hugetlb lists KVM: guest_memfd: Track faultability within a struct kvm_gmem_private KVM: guest_memfd: Allow mmapping guest_memfd files KVM: guest_memfd: Use vm_type to determine default faultability KVM: Handle conversions in the SET_MEMORY_ATTRIBUTES ioctl KVM: guest_memfd: Handle folio preparation for guest_memfd mmap KVM: selftests: Allow vm_set_memory_attributes to be used without asserting return value of 0 KVM: selftests: Test using guest_memfd memory from userspace KVM: selftests: Test guest_memfd memory sharing between guest and host KVM: selftests: Add notes in private_mem_kvm_exits_test for mmap-able guest_memfd KVM: selftests: Test that pinned pages block KVM from setting memory attributes to PRIVATE KVM: selftests: Refactor vm_mem_add to be more flexible KVM: selftests: Add helper to perform madvise by memslots KVM: selftests: Update private_mem_conversions_test for mmap()able guest_memfd Vishal Annapurve (2): KVM: guest_memfd: Split HugeTLB pages for guest_memfd use KVM: guest_memfd: Dynamically split/reconstruct HugeTLB page fs/hugetlbfs/inode.c | 35 +- include/linux/hugetlb.h | 54 +- include/linux/kvm_host.h | 1 + include/linux/mempolicy.h | 2 + include/linux/mm.h | 1 + include/uapi/linux/kvm.h | 26 + include/uapi/linux/magic.h | 1 + mm/hugetlb.c | 346 ++-- mm/hugetlb_vmemmap.h | 11 - mm/mempolicy.c | 36 +- mm/truncate.c | 26 +- tools/include/linux/kernel.h | 4 +- tools/testing/selftests/kvm/Makefile | 3 + .../kvm/guest_memfd_hugetlb_reporting_test.c | 222 +++ .../selftests/kvm/guest_memfd_pin_test.c | 104 ++ .../selftests/kvm/guest_memfd_sharing_test.c | 160 ++ .../testing/selftests/kvm/guest_memfd_test.c | 238 ++- .../testing/selftests/kvm/include/kvm_util.h | 45 +- .../testing/selftests/kvm/include/test_util.h | 18 + tools/testing/selftests/kvm/lib/kvm_util.c | 443 +++-- tools/testing/selftests/kvm/lib/test_util.c | 99 ++ .../kvm/x86_64/private_mem_conversions_test.c | 158 +- .../x86_64/private_mem_conversions_test.sh | 91 + .../kvm/x86_64/private_mem_kvm_exits_test.c | 11 +- virt/kvm/guest_memfd.c | 1563 ++++++++++++++++- virt/kvm/kvm_main.c | 17 + virt/kvm/kvm_mm.h | 16 + 27 files changed, 3288 insertions(+), 443 deletions(-) create mode 100644 tools/testing/selftests/kvm/guest_memfd_hugetlb_reporting_test.c create mode 100644 tools/testing/selftests/kvm/guest_memfd_pin_test.c create mode 100644 tools/testing/selftests/kvm/guest_memfd_sharing_test.c create mode 100755 tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.sh -- 2.46.0.598.g6f2099f65c-goog

1 week, 5 days

17
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[PATCH v2 00/19] iommufd: Add VIOMMU infrastructure (Part-1)

by Nicolin Chen

This series introduces a new VIOMMU infrastructure and related ioctls. IOMMUFD has been using the HWPT infrastructure for all cases, including a nested IO page table support. Yet, there're limitations for an HWPT-based structure to support some advanced HW-accelerated features, such as CMDQV on NVIDIA Grace, and HW-accelerated vIOMMU on AMD. Even for a multi-IOMMU environment, it is not straightforward for nested HWPTs to share the same parent HWPT (stage-2 IO pagetable), with the HWPT infrastructure alone. The new VIOMMU object is an additional layer, between the nested HWPT and its parent HWPT, to give to both the IOMMUFD core and an IOMMU driver an additional structure to support HW-accelerated feature: ---------------------------- ---------------- | | paging_hwpt0 | | hwpt_nested0 |--->| viommu0 ------------------ ---------------- | | HW-accel feats | ---------------------------- On a multi-IOMMU system, the VIOMMU object can be instanced to the number of vIOMMUs in a guest VM, while holding the same parent HWPT to share the stage-2 IO pagetable. Each VIOMMU then just need to only allocate its own VMID to attach the shared stage-2 IO pagetable to the physical IOMMU: ---------------------------- ---------------- | | paging_hwpt0 | | hwpt_nested0 |--->| viommu0 ------------------ ---------------- | | VMID0 | ---------------------------- ---------------------------- ---------------- | | paging_hwpt0 | | hwpt_nested1 |--->| viommu1 ------------------ ---------------- | | VMID1 | ---------------------------- As an initial part-1, add ioctls to support a VIOMMU-based invalidation: IOMMUFD_CMD_VIOMMU_ALLOC to allocate a VIOMMU object IOMMUFD_CMD_VIOMMU_SET/UNSET_VDEV_ID to set/clear device's virtual ID (Resue IOMMUFD_CMD_HWPT_INVALIDATE for a VIOMMU object to flush cache by a given driver data) Worth noting that the VDEV_ID is for a per-VIOMMU device list for drivers to look up the device's physical instance from its virtual ID in a VM. It is essential for a VIOMMU-based invalidation where the request contains a device's virtual ID for its device cache flush, e.g. ATC invalidation. As for the implementation of the series, add an IOMMU_VIOMMU_TYPE_DEFAULT type for a core-allocated-core-managed VIOMMU object, allowing drivers to simply hook a default viommu ops for viommu-based invalidation alone. And provide some viommu helpers to drivers for VDEV_ID translation and parent domain lookup. Add VIOMMU invalidation support to ARM SMMUv3 driver for a real world use case. This adds supports of arm-smmuv-v3's CMDQ_OP_ATC_INV and CMDQ_OP_CFGI_CD/ALL commands, supplementing HWPT-based invalidations. In the future, drivers will also be able to choose a driver-managed type to hold its own structure by adding a new type to enum iommu_viommu_type. More VIOMMU-based structures and ioctls will be introduced in part-2/3 to support a driver-managed VIOMMU, e.g. VQUEUE object for a HW accelerated queue, VIRQ (or VEVENT) object for IRQ injections. Although we repurposed the VIOMMU object from an earlier RFC discussion, for a referece: https://lore.kernel.org/all/cover.1712978212.git.nicolinc@nvidia.com/ This series is on Github: https://github.com/nicolinc/iommufd/commits/iommufd_viommu_p1-v2 Paring QEMU branch for testing: https://github.com/nicolinc/qemu/commits/wip/for_iommufd_viommu_p1-v2 Changelog v2 * Limited vdev_id to one per idev * Added a rw_sem to protect the vdev_id list * Reworked driver-level APIs with proper lockings * Added a new viommu_api file for IOMMUFD_DRIVER config * Dropped useless iommu_dev point from the viommu structure * Added missing index numnbers to new types in the uAPI header * Dropped IOMMU_VIOMMU_INVALIDATE uAPI; Instead, reuse the HWPT one * Reworked mock_viommu_cache_invalidate() using the new iommu helper * Reordered details of set/unset_vdev_id handlers for proper lockings * Added arm_smmu_cache_invalidate_user patch from Jason's nesting series v1 https://lore.kernel.org/all/cover.1723061377.git.nicolinc@nvidia.com/ Thanks! Nicolin Jason Gunthorpe (3): iommu: Add iommu_copy_struct_from_full_user_array helper iommu/arm-smmu-v3: Allow ATS for IOMMU_DOMAIN_NESTED iommu/arm-smmu-v3: Update comments about ATS and bypass Nicolin Chen (16): iommufd: Reorder struct forward declarations iommufd/viommu: Add IOMMUFD_OBJ_VIOMMU and IOMMU_VIOMMU_ALLOC ioctl iommu: Pass in a viommu pointer to domain_alloc_user op iommufd: Allow pt_id to carry viommu_id for IOMMU_HWPT_ALLOC iommufd/selftest: Add IOMMU_VIOMMU_ALLOC test coverage iommufd/viommu: Add IOMMU_VIOMMU_SET/UNSET_VDEV_ID ioctl iommufd/selftest: Add IOMMU_VIOMMU_SET/UNSET_VDEV_ID test coverage iommufd/viommu: Add cache_invalidate for IOMMU_VIOMMU_TYPE_DEFAULT iommufd: Allow hwpt_id to carry viommu_id for IOMMU_HWPT_INVALIDATE iommufd/viommu: Add vdev_id helpers for IOMMU drivers iommufd/selftest: Add mock_viommu_invalidate_user op iommufd/selftest: Add IOMMU_TEST_OP_DEV_CHECK_CACHE test command iommufd/selftest: Add VIOMMU coverage for IOMMU_HWPT_INVALIDATE ioctl iommufd/viommu: Add iommufd_viommu_to_parent_domain helper iommu/arm-smmu-v3: Add arm_smmu_cache_invalidate_user iommu/arm-smmu-v3: Add arm_smmu_viommu_cache_invalidate drivers/iommu/amd/iommu.c | 1 + drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 218 ++++++++++++++- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 3 + drivers/iommu/intel/iommu.c | 1 + drivers/iommu/iommufd/Makefile | 5 +- drivers/iommu/iommufd/device.c | 12 + drivers/iommu/iommufd/hw_pagetable.c | 59 +++- drivers/iommu/iommufd/iommufd_private.h | 37 +++ drivers/iommu/iommufd/iommufd_test.h | 30 ++ drivers/iommu/iommufd/main.c | 12 + drivers/iommu/iommufd/selftest.c | 101 ++++++- drivers/iommu/iommufd/viommu.c | 196 +++++++++++++ drivers/iommu/iommufd/viommu_api.c | 53 ++++ include/linux/iommu.h | 56 +++- include/linux/iommufd.h | 51 +++- include/uapi/linux/iommufd.h | 117 +++++++- tools/testing/selftests/iommu/iommufd.c | 259 +++++++++++++++++- tools/testing/selftests/iommu/iommufd_utils.h | 126 +++++++++ 18 files changed, 1299 insertions(+), 38 deletions(-) create mode 100644 drivers/iommu/iommufd/viommu.c create mode 100644 drivers/iommu/iommufd/viommu_api.c -- 2.43.0

1 week, 6 days

7
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[PATCH v3 0/3] introduce PIDFD_SELF* sentinels

by Lorenzo Stoakes

If you wish to utilise a pidfd interface to refer to the current process or thread it is rather cumbersome, requiring something like: int pidfd = pidfd_open(getpid(), 0 or PIDFD_THREAD); ... close(pidfd); Or the equivalent call opening /proc/self. It is more convenient to use a sentinel value to indicate to an interface that accepts a pidfd that we simply wish to refer to the current process thread. This series introduces sentinels for this purposes which can be passed as the pidfd in this instance rather than having to establish a dummy fd for this purpose. It is useful to refer to both the current thread from the userland's perspective for which we use PIDFD_SELF, and the current process from the userland's perspective, for which we use PIDFD_SELF_PROCESS. There is unfortunately some confusion between the kernel and userland as to what constitutes a process - a thread from the userland perspective is a process in userland, and a userland process is a thread group (more specifically the thread group leader from the kernel perspective). We therefore alias things thusly: * PIDFD_SELF_THREAD aliased by PIDFD_SELF - use PIDTYPE_PID. * PIDFD_SELF_THREAD_GROUP alised by PIDFD_SELF_PROCESS - use PIDTYPE_TGID. In all of the kernel code we refer to PIDFD_SELF_THREAD and PIDFD_SELF_THREAD_GROUP. However we expect users to use PIDFD_SELF and PIDFD_SELF_PROCESS. This matters for cases where, for instance, a user unshare()'s FDs or does thread-specific signal handling and where the user would be hugely confused if the FDs referenced or signal processed referred to the thread group leader rather than the individual thread. We ensure that pidfd_send_signal() and pidfd_getfd() work correctly, and assert as much in selftests. All other interfaces except setns() will work implicitly with this new interface, however it doesn't make sense to test waitid(P_PIDFD, ...) as waiting on ourselves is a blocking operation. In the case of setns() we explicitly disallow use of PIDFD_SELF* as it doesn't make sense to obtain the namespaces of our own process, and it would require work to implement this functionality there that would be of no use. We also do not provide the ability to utilise PIDFD_SELF* in ordinary fd operations such as open() or poll(), as this would require extensive work and be of no real use. v3: * Do not fput() an invalid fd as reported by kernel test bot. * Fix unintended churn from moving variable declaration. v2: * Fix tests as reported by Shuah. * Correct RFC version lore link. https://lore.kernel.org/linux-mm/cover.1728643714.git.lorenzo.stoakes@oracl… Non-RFC v1: * Removed RFC tag - there seems to be general consensus that this change is a good idea, but perhaps some debate to be had on implementation. It seems sensible then to move forward with the RFC flag removed. * Introduced PIDFD_SELF_THREAD, PIDFD_SELF_THREAD_GROUP and their aliases PIDFD_SELF and PIDFD_SELF_PROCESS respectively. * Updated testing accordingly. https://lore.kernel.org/linux-mm/cover.1728578231.git.lorenzo.stoakes@oracl… RFC version: https://lore.kernel.org/linux-mm/cover.1727644404.git.lorenzo.stoakes@oracl… Lorenzo Stoakes (3): pidfd: extend pidfd_get_pid() and de-duplicate pid lookup pidfd: add PIDFD_SELF_* sentinels to refer to own thread/process selftests: pidfd: add tests for PIDFD_SELF_* include/linux/pid.h | 43 +++++- include/uapi/linux/pidfd.h | 15 ++ kernel/exit.c | 3 +- kernel/nsproxy.c | 1 + kernel/pid.c | 73 ++++++--- kernel/signal.c | 26 +--- tools/testing/selftests/pidfd/pidfd.h | 8 + .../selftests/pidfd/pidfd_getfd_test.c | 141 ++++++++++++++++++ .../selftests/pidfd/pidfd_setns_test.c | 11 ++ tools/testing/selftests/pidfd/pidfd_test.c | 76 ++++++++-- 10 files changed, 342 insertions(+), 55 deletions(-) -- 2.46.2

2 weeks, 3 days

6
31
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[RFC PATCH 00/11] New KVM ioctl to link a gmem inode to a new gmem file

by Ackerley Tng

Hello, This patchset builds upon the code at https://lore.kernel.org/lkml/20230718234512.1690985-1-seanjc@google.com/T/. This code is available at https://github.com/googleprodkernel/linux-cc/tree/kvm-gmem-link-migrate-rfc…. In guest_mem v11, a split file/inode model was proposed, where memslot bindings belong to the file and pages belong to the inode. This model lends itself well to having different VMs use separate files pointing to the same inode. This RFC proposes an ioctl, KVM_LINK_GUEST_MEMFD, that takes a VM and a gmem fd, and returns another gmem fd referencing a different file and associated with VM. This RFC also includes an update to KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM to migrate memory context (slot->arch.lpage_info and kvm->mem_attr_array) from source to destination vm, intra-host. Intended usage of the two ioctls: 1. Source VM’s fd is passed to destination VM via unix sockets 2. Destination VM uses new ioctl KVM_LINK_GUEST_MEMFD to link source VM’s fd to a new fd. 3. Destination VM will pass new fds to KVM_SET_USER_MEMORY_REGION, which will bind the new file, pointing to the same inode that the source VM’s file points to, to memslots 4. Use KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM to move kvm->mem_attr_array and slot->arch.lpage_info to the destination VM. 5. Run the destination VM as per normal Some other approaches considered were: + Using the linkat() syscall, but that requires a mount/directory for a source fd to be linked to + Using the dup() syscall, but that only duplicates the fd, and both fds point to the same file --- Ackerley Tng (11): KVM: guest_mem: Refactor out kvm_gmem_alloc_file() KVM: guest_mem: Add ioctl KVM_LINK_GUEST_MEMFD KVM: selftests: Add tests for KVM_LINK_GUEST_MEMFD ioctl KVM: selftests: Test transferring private memory to another VM KVM: x86: Refactor sev's flag migration_in_progress to kvm struct KVM: x86: Refactor common code out of sev.c KVM: x86: Refactor common migration preparation code out of sev_vm_move_enc_context_from KVM: x86: Let moving encryption context be configurable KVM: x86: Handle moving of memory context for intra-host migration KVM: selftests: Generalize migration functions from sev_migrate_tests.c KVM: selftests: Add tests for migration of private mem arch/x86/include/asm/kvm_host.h | 4 +- arch/x86/kvm/svm/sev.c | 85 ++----- arch/x86/kvm/svm/svm.h | 3 +- arch/x86/kvm/x86.c | 221 +++++++++++++++++- arch/x86/kvm/x86.h | 6 + include/linux/kvm_host.h | 18 ++ include/uapi/linux/kvm.h | 8 + tools/testing/selftests/kvm/Makefile | 1 + .../testing/selftests/kvm/guest_memfd_test.c | 42 ++++ .../selftests/kvm/include/kvm_util_base.h | 31 +++ .../kvm/x86_64/private_mem_migrate_tests.c | 93 ++++++++ .../selftests/kvm/x86_64/sev_migrate_tests.c | 48 ++-- virt/kvm/guest_mem.c | 151 ++++++++++-- virt/kvm/kvm_main.c | 10 + virt/kvm/kvm_mm.h | 7 + 15 files changed, 596 insertions(+), 132 deletions(-) create mode 100644 tools/testing/selftests/kvm/x86_64/private_mem_migrate_tests.c -- 2.41.0.640.ga95def55d0-goog

2 weeks, 5 days

3
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[PATCH v1 1/3] selftests: pidfd: add missing sys/mount.h include in pidfd_fdinfo_test.c

by Peter Seiderer

Fix compile on openSUSE Tumbleweed (gcc-14.2.1, glibc-2.40): - add missing sys/mount.h include Fixes: pidfd_fdinfo_test.c: In function ‘child_fdinfo_nspid_test’: pidfd_fdinfo_test.c:230:13: error: implicit declaration of function ‘mount’ [-Wimplicit-function-declaration] 230 | r = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0); | ^~~~~ Signed-off-by: Peter Seiderer <ps.report(a)gmx.net> --- tools/testing/selftests/pidfd/pidfd_fdinfo_test.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c b/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c index f062a986e382..f718aac75068 100644 --- a/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c +++ b/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c @@ -13,6 +13,7 @@ #include <syscall.h> #include <sys/wait.h> #include <sys/mman.h> +#include <sys/mount.h> #include "pidfd.h" #include "../kselftest.h" -- 2.47.1

3 weeks, 4 days

2
5
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[PATCH v6 0/5] userfaultfd move option

by Suren Baghdasaryan

This patch series introduces UFFDIO_MOVE feature to userfaultfd, which has long been implemented and maintained by Andrea in his local tree [1], but was not upstreamed due to lack of use cases where this approach would be better than allocating a new page and copying the contents. Previous upstraming attempts could be found at [6] and [7]. UFFDIO_COPY performs ~20% better than UFFDIO_MOVE when the application needs pages to be allocated [2]. However, with UFFDIO_MOVE, if pages are available (in userspace) for recycling, as is usually the case in heap compaction algorithms, then we can avoid the page allocation and memcpy (done by UFFDIO_COPY). Also, since the pages are recycled in the userspace, we avoid the need to release (via madvise) the pages back to the kernel [3]. We see over 40% reduction (on a Google pixel 6 device) in the compacting thread’s completion time by using UFFDIO_MOVE vs. UFFDIO_COPY. This was measured using a benchmark that emulates a heap compaction implementation using userfaultfd (to allow concurrent accesses by application threads). More details of the usecase are explained in [3]. Furthermore, UFFDIO_MOVE enables moving swapped-out pages without touching them within the same vma. Today, it can only be done by mremap, however it forces splitting the vma. TODOs for follow-up improvements: - cross-mm support. Known differences from single-mm and missing pieces: - memcg recharging (might need to isolate pages in the process) - mm counters - cross-mm deposit table moves - cross-mm test - document the address space where src and dest reside in struct uffdio_move - TLB flush batching. Will require extensive changes to PTL locking in move_pages_pte(). OTOH that might let us reuse parts of mremap code. Changes since v5 [10]: - added logic to split large folios in move_pages_pte(), per David Hildenbrand - added check for PAE before split_huge_pmd() to avoid the split if the move operation can't be done - replaced calls to default_huge_page_size() with read_pmd_pagesize() in uffd_move_pmd test, per David Hildenbrand - fixed the condition in uffd_move_test_common() checking if area alignment is needed Changes since v4 [9]: - added Acked-by in patch 1, per Peter Xu - added description for ctx, mm and mode parameters of move_pages(), per kernel test robot - added Reviewed-by's, per Peter Xu and Axel Rasmussen - removed unused operations in uffd_test_case_ops - refactored uffd-unit-test changes to avoid using global variables and handle pmd moves without page size overrides, per Peter Xu Changes since v3 [8]: - changed retry path in folio_lock_anon_vma_read() to unlock and then relock RCU, per Peter Xu - removed cross-mm support from initial patchset, per David Hildenbrand - replaced BUG_ONs with VM_WARN_ON or WARN_ON_ONCE, per David Hildenbrand - added missing cache flushing, per Lokesh Gidra and Peter Xu - updated manpage text in the patch description, per Peter Xu - renamed internal functions from "remap" to "move", per Peter Xu - added mmap_changing check after taking mmap_lock, per Peter Xu - changed uffd context check to ensure dst_mm is registered onto uffd we are operating on, Peter Xu and David Hildenbrand - changed to non-maybe variants of maybe*_mkwrite(), per David Hildenbrand - fixed warning for CONFIG_TRANSPARENT_HUGEPAGE=n, per kernel test robot - comments cleanup, per David Hildenbrand and Peter Xu - checks for VM_IO,VM_PFNMAP,VM_HUGETLB,..., per David Hildenbrand - prevent moving pinned pages, per Peter Xu - changed uffd tests to call move uffd_test_ctx_clear() at the end of the test run instead of in the beginning of the next run - added support for testcase-specific ops - added test for moving PMD-aligned blocks Changes since v2 [5]: - renamed UFFDIO_REMAP to UFFDIO_MOVE, per David Hildenbrand - rebase over mm-unstable to use folio_move_anon_rmap(), per David Hildenbrand - added text for manpage explaining DONTFORK and KSM requirements for this feature, per David Hildenbrand - check for anon_vma changes in the fast path of folio_lock_anon_vma_read, per Peter Xu - updated the title and description of the first patch, per David Hildenbrand - updating comments in folio_lock_anon_vma_read() explaining the need for anon_vma checks, per David Hildenbrand - changed all mapcount checks to PageAnonExclusive, per Jann Horn and David Hildenbrand - changed counters in remap_swap_pte() from MM_ANONPAGES to MM_SWAPENTS, per Jann Horn - added a check for PTE change after folio is locked in remap_pages_pte(), per Jann Horn - added handling of PMD migration entries and bailout when pmd_devmap(), per Jann Horn - added checks to ensure both src and dst VMAs are writable, per Peter Xu - added UFFD_FEATURE_MOVE, per Peter Xu - removed obsolete comments, per Peter Xu - renamed remap_anon_pte to remap_present_pte, per Peter Xu - added a comment for folio_get_anon_vma() explaining the need for anon_vma checks, per Peter Xu - changed error handling in remap_pages() to make it more clear, per Peter Xu - changed EFAULT to EAGAIN to retry when a hugepage appears or disappears from under us, per Peter Xu - added links to previous upstreaming attempts, per David Hildenbrand Changes since v1 [4]: - add mmget_not_zero in userfaultfd_remap, per Jann Horn - removed extern from function definitions, per Matthew Wilcox - converted to folios in remap_pages_huge_pmd, per Matthew Wilcox - use PageAnonExclusive in remap_pages_huge_pmd, per David Hildenbrand - handle pgtable transfers between MMs, per Jann Horn - ignore concurrent A/D pte bit changes, per Jann Horn - split functions into smaller units, per David Hildenbrand - test for folio_test_large in remap_anon_pte, per Matthew Wilcox - use pte_swp_exclusive for swapcount check, per David Hildenbrand - eliminated use of mmu_notifier_invalidate_range_start_nonblock, per Jann Horn - simplified THP alignment checks, per Jann Horn - refactored the loop inside remap_pages, per Jann Horn - additional clarifying comments, per Jann Horn Main changes since Andrea's last version [1]: - Trivial translations from page to folio, mmap_sem to mmap_lock - Replace pmd_trans_unstable() with pte_offset_map_nolock() and handle its possible failure - Move pte mapping into remap_pages_pte to allow for retries when source page or anon_vma is contended. Since pte_offset_map_nolock() start RCU read section, we can't block anymore after mapping a pte, so have to unmap the ptesm do the locking and retry. - Add and use anon_vma_trylock_write() to avoid blocking while in RCU read section. - Accommodate changes in mmu_notifier_range_init() API, switch to mmu_notifier_invalidate_range_start_nonblock() to avoid blocking while in RCU read section. - Open-code now removed __swp_swapcount() - Replace pmd_read_atomic() with pmdp_get_lockless() - Add new selftest for UFFDIO_MOVE [1] https://gitlab.com/aarcange/aa/-/commit/2aec7aea56b10438a3881a20a411aa4b1fc… [2] https://lore.kernel.org/all/1425575884-2574-1-git-send-email-aarcange@redha… [3] https://lore.kernel.org/linux-mm/CA+EESO4uO84SSnBhArH4HvLNhaUQ5nZKNKXqxRCyj… [4] https://lore.kernel.org/all/20230914152620.2743033-1-surenb@google.com/ [5] https://lore.kernel.org/all/20230923013148.1390521-1-surenb@google.com/ [6] https://lore.kernel.org/all/1425575884-2574-21-git-send-email-aarcange@redh… [7] https://lore.kernel.org/all/cover.1547251023.git.blake.caldwell@colorado.ed… [8] https://lore.kernel.org/all/20231009064230.2952396-1-surenb@google.com/ [9] https://lore.kernel.org/all/20231028003819.652322-1-surenb@google.com/ [10] https://lore.kernel.org/all/20231121171643.3719880-1-surenb@google.com/ Andrea Arcangeli (2): mm/rmap: support move to different root anon_vma in folio_move_anon_rmap() userfaultfd: UFFDIO_MOVE uABI Suren Baghdasaryan (3): selftests/mm: call uffd_test_ctx_clear at the end of the test selftests/mm: add uffd_test_case_ops to allow test case-specific operations selftests/mm: add UFFDIO_MOVE ioctl test Documentation/admin-guide/mm/userfaultfd.rst | 3 + fs/userfaultfd.c | 72 +++ include/linux/rmap.h | 5 + include/linux/userfaultfd_k.h | 11 + include/uapi/linux/userfaultfd.h | 29 +- mm/huge_memory.c | 122 ++++ mm/khugepaged.c | 3 + mm/rmap.c | 30 + mm/userfaultfd.c | 614 +++++++++++++++++++ tools/testing/selftests/mm/uffd-common.c | 39 +- tools/testing/selftests/mm/uffd-common.h | 9 + tools/testing/selftests/mm/uffd-stress.c | 5 +- tools/testing/selftests/mm/uffd-unit-tests.c | 192 ++++++ 13 files changed, 1130 insertions(+), 4 deletions(-) -- 2.43.0.rc2.451.g8631bc7472-goog

1 month

7
43
0 0

[PATCH bpf-next v2 0/6] selftests/bpf: Various sockmap-related fixes

by Michal Luczaj

Series takes care of few bugs and missing features with the aim to improve the test coverage of sockmap/sockhash. Last patch is a create_pair() rewrite making use of __attribute__((cleanup)) to handle socket fd lifetime. Signed-off-by: Michal Luczaj <mhal(a)rbox.co> --- Changes in v2: - Rebase on bpf-next (Jakub) - Use cleanup helpers from kernel's cleanup.h (Jakub) - Fix subject of patch 3, rephrase patch 4, use correct prefix - Link to v1: https://lore.kernel.org/r/20240724-sockmap-selftest-fixes-v1-0-46165d224712… Changes in v1: - No declarations in function body (Jakub) - Don't touch output arguments until function succeeds (Jakub) - Link to v0: https://lore.kernel.org/netdev/027fdb41-ee11-4be0-a493-22f28a1abd7c@rbox.co/ --- Michal Luczaj (6): selftests/bpf: Support more socket types in create_pair() selftests/bpf: Socket pair creation, cleanups selftests/bpf: Simplify inet_socketpair() and vsock_socketpair_connectible() selftests/bpf: Honour the sotype of af_unix redir tests selftests/bpf: Exercise SOCK_STREAM unix_inet_redir_to_connected() selftests/bpf: Introduce __attribute__((cleanup)) in create_pair() .../selftests/bpf/prog_tests/sockmap_basic.c | 28 ++-- .../selftests/bpf/prog_tests/sockmap_helpers.h | 149 ++++++++++++++------- .../selftests/bpf/prog_tests/sockmap_listen.c | 117 ++-------------- 3 files changed, 124 insertions(+), 170 deletions(-) --- base-commit: 92cc2456e9775dc4333fb4aa430763ae4ac2f2d9 change-id: 20240729-selftest-sockmap-fixes-bcca996e143b Best regards, -- Michal Luczaj <mhal(a)rbox.co>

1 month, 2 weeks

3
26
0 0

[PATCH v2] selftests/ptrace/get_syscall_info: fix for MIPS n32

by Dmitry V. Levin

MIPS n32 is one of two ILP32 architectures supported by the kernel that have 64-bit syscall arguments (another one is x32). When this test passed 32-bit arguments to syscall(), they were sign-extended in libc, PTRACE_GET_SYSCALL_INFO reported these sign-extended 64-bit values, and the test complained about the mismatch. Fix this by passing arguments of the appropriate type to syscall(), which is "unsigned long long" on MIPS n32, and __kernel_ulong_t on other architectures. As a side effect, this also extends the test on all 64-bit architectures by choosing constants that don't fit into 32-bit integers. Signed-off-by: Dmitry V. Levin <ldv(a)strace.io> --- v2: Fixed MIPS #ifdef. .../selftests/ptrace/get_syscall_info.c | 53 +++++++++++-------- 1 file changed, 32 insertions(+), 21 deletions(-) diff --git a/tools/testing/selftests/ptrace/get_syscall_info.c b/tools/testing/selftests/ptrace/get_syscall_info.c index 5bcd1c7b5be6..2970f72d66d3 100644 --- a/tools/testing/selftests/ptrace/get_syscall_info.c +++ b/tools/testing/selftests/ptrace/get_syscall_info.c @@ -11,8 +11,19 @@ #include <err.h> #include <signal.h> #include <asm/unistd.h> +#include <linux/types.h> #include "linux/ptrace.h" +#if defined(_MIPS_SIM) && _MIPS_SIM == _MIPS_SIM_NABI32 +/* + * MIPS N32 is the only architecture where __kernel_ulong_t + * does not match the bitness of syscall arguments. + */ +typedef unsigned long long kernel_ulong_t; +#else +typedef __kernel_ulong_t kernel_ulong_t; +#endif + static int kill_tracee(pid_t pid) { @@ -42,37 +53,37 @@ sys_ptrace(int request, pid_t pid, unsigned long addr, unsigned long data) TEST(get_syscall_info) { - static const unsigned long args[][7] = { + const kernel_ulong_t args[][7] = { /* a sequence of architecture-agnostic syscalls */ { __NR_chdir, - (unsigned long) "", - 0xbad1fed1, - 0xbad2fed2, - 0xbad3fed3, - 0xbad4fed4, - 0xbad5fed5 + (uintptr_t) "", + (kernel_ulong_t) 0xdad1bef1bad1fed1ULL, + (kernel_ulong_t) 0xdad2bef2bad2fed2ULL, + (kernel_ulong_t) 0xdad3bef3bad3fed3ULL, + (kernel_ulong_t) 0xdad4bef4bad4fed4ULL, + (kernel_ulong_t) 0xdad5bef5bad5fed5ULL }, { __NR_gettid, - 0xcaf0bea0, - 0xcaf1bea1, - 0xcaf2bea2, - 0xcaf3bea3, - 0xcaf4bea4, - 0xcaf5bea5 + (kernel_ulong_t) 0xdad0bef0caf0bea0ULL, + (kernel_ulong_t) 0xdad1bef1caf1bea1ULL, + (kernel_ulong_t) 0xdad2bef2caf2bea2ULL, + (kernel_ulong_t) 0xdad3bef3caf3bea3ULL, + (kernel_ulong_t) 0xdad4bef4caf4bea4ULL, + (kernel_ulong_t) 0xdad5bef5caf5bea5ULL }, { __NR_exit_group, 0, - 0xfac1c0d1, - 0xfac2c0d2, - 0xfac3c0d3, - 0xfac4c0d4, - 0xfac5c0d5 + (kernel_ulong_t) 0xdad1bef1fac1c0d1ULL, + (kernel_ulong_t) 0xdad2bef2fac2c0d2ULL, + (kernel_ulong_t) 0xdad3bef3fac3c0d3ULL, + (kernel_ulong_t) 0xdad4bef4fac4c0d4ULL, + (kernel_ulong_t) 0xdad5bef5fac5c0d5ULL } }; - const unsigned long *exp_args; + const kernel_ulong_t *exp_args; pid_t pid = fork(); @@ -154,7 +165,7 @@ TEST(get_syscall_info) } ASSERT_LT(0, (rc = sys_ptrace(PTRACE_GET_SYSCALL_INFO, pid, size, - (unsigned long) &info))) { + (uintptr_t) &info))) { LOG_KILL_TRACEE("PTRACE_GET_SYSCALL_INFO: %m"); } ASSERT_EQ(expected_none_size, rc) { @@ -177,7 +188,7 @@ TEST(get_syscall_info) case SIGTRAP | 0x80: ASSERT_LT(0, (rc = sys_ptrace(PTRACE_GET_SYSCALL_INFO, pid, size, - (unsigned long) &info))) { + (uintptr_t) &info))) { LOG_KILL_TRACEE("PTRACE_GET_SYSCALL_INFO: %m"); } switch (ptrace_stop) { -- ldv

1 month, 2 weeks

3
5
0 0

[PATCH v4 00/30] context_tracking,x86: Defer some IPIs until a user->kernel transition

by Valentin Schneider

Context ======= We've observed within Red Hat that isolated, NOHZ_FULL CPUs running a pure-userspace application get regularly interrupted by IPIs sent from housekeeping CPUs. Those IPIs are caused by activity on the housekeeping CPUs leading to various on_each_cpu() calls, e.g.: 64359.052209596 NetworkManager 0 1405 smp_call_function_many_cond (cpu=0, func=do_kernel_range_flush) smp_call_function_many_cond+0x1 smp_call_function+0x39 on_each_cpu+0x2a flush_tlb_kernel_range+0x7b __purge_vmap_area_lazy+0x70 _vm_unmap_aliases.part.42+0xdf change_page_attr_set_clr+0x16a set_memory_ro+0x26 bpf_int_jit_compile+0x2f9 bpf_prog_select_runtime+0xc6 bpf_prepare_filter+0x523 sk_attach_filter+0x13 sock_setsockopt+0x92c __sys_setsockopt+0x16a __x64_sys_setsockopt+0x20 do_syscall_64+0x87 entry_SYSCALL_64_after_hwframe+0x65 The heart of this series is the thought that while we cannot remove NOHZ_FULL CPUs from the list of CPUs targeted by these IPIs, they may not have to execute the callbacks immediately. Anything that only affects kernelspace can wait until the next user->kernel transition, providing it can be executed "early enough" in the entry code. The original implementation is from Peter [1]. Nicolas then added kernel TLB invalidation deferral to that [2], and I picked it up from there. Deferral approach ================= Storing each and every callback, like a secondary call_single_queue turned out to be a no-go: the whole point of deferral is to keep NOHZ_FULL CPUs in userspace for as long as possible - no signal of any form would be sent when deferring an IPI. This means that any form of queuing for deferred callbacks would end up as a convoluted memory leak. Deferred IPIs must thus be coalesced, which this series achieves by assigning IPIs a "type" and having a mapping of IPI type to callback, leveraged upon kernel entry. What about IPIs whose callback take a parameter, you may ask? Peter suggested during OSPM23 [3] that since on_each_cpu() targets housekeeping CPUs *and* isolated CPUs, isolated CPUs can access either global or housekeeping-CPU-local state to "reconstruct" the data that would have been sent via the IPI. This series does not affect any IPI callback that requires an argument, but the approach would remain the same (one coalescable callback executed on kernel entry). Kernel entry vs execution of the deferred operation =================================================== This is what I've referred to as the "Danger Zone" during my LPC24 talk [4]. There is a non-zero length of code that is executed upon kernel entry before the deferred operation can be itself executed (i.e. before we start getting into context_tracking.c proper), i.e.: idtentry_func_foo() <--- we're in the kernel irqentry_enter() enter_from_user_mode() __ct_user_exit() ct_kernel_enter_state() ct_work_flush() <--- deferred operation is executed here This means one must take extra care to what can happen in the early entry code, and that <bad things> cannot happen. For instance, we really don't want to hit instructions that have been modified by a remote text_poke() while we're on our way to execute a deferred sync_core(). Patches doing the actual deferral have more detail on this. Patches ======= o Patches 1-2 are standalone objtool cleanups. o Patches 3-4 add an RCU testing feature. o Patches 5-6 add infrastructure for annotating static keys and static calls that may be used in noinstr code (courtesy of Josh). o Patches 7-19 use said annotations on relevant keys / calls. o Patch 20 enforces proper usage of said annotations (courtesy of Josh). o Patches 21-23 fiddle with CT_STATE* within context tracking o Patches 24-29 add the actual IPI deferral faff o Patch 30 adds a freebie: deferring IPIs for NOHZ_IDLE. Not tested that much! if you care about battery-powered devices and energy consumption, go give it a try! Patches are also available at: https://gitlab.com/vschneid/linux.git -b redhat/isolirq/defer/v4 Stuff I'd like eyes and neurons on ================================== Context-tracking vs idle. Patch 22 "improves" the situation by adding an IDLE->KERNEL transition when getting an IRQ while idle, but it leaves the following window: ~> IRQ ct_nmi_enter() state = state + CT_STATE_KERNEL - CT_STATE_IDLE [...] ct_nmi_exit() state = state - CT_STATE_KERNEL + CT_STATE_IDLE [...] /!\ CT_STATE_IDLE here while we're really in kernelspace! /!\ ct_cpuidle_exit() state = state + CT_STATE_KERNEL - CT_STATE_IDLE Said window is contained within cpu_idle_poll() and the cpuidle call within cpuidle_enter_state(), both being noinstr (the former is __cpuidle which is noinstr itself). Thus objtool will consider it as early entry and will warn accordingly of any static key / call misuse, so the damage is somewhat contained, but it's not ideal. I tried fiddling with this but idle polling likes being annoying, as it is shaped like so: ct_cpuidle_enter(); raw_local_irq_enable(); while (!tif_need_resched() && (cpu_idle_force_poll || tick_check_broadcast_expired())) cpu_relax(); raw_local_irq_disable(); ct_cpuidle_exit(); IOW, getting an IRQ that doesn't end up setting NEED_RESCHED while idle-polling doesn't come near ct_cpuidle_exit(), which prevents me from having the outermost ct_nmi_exit() leave the state as CT_STATE_KERNEL (rather than CT_STATE_IDLE). Testing ======= Xeon E5-2699 system with SMToff, NOHZ_FULL, isolated CPUs. RHEL9 userspace. Workload is using rteval (kernel compilation + hackbench) on housekeeping CPUs and a dummy stay-in-userspace loop on the isolated CPUs. The main invocation is: $ trace-cmd record -e "csd_queue_cpu" -f "cpu & CPUS{$ISOL_CPUS}" \ -e "ipi_send_cpumask" -f "cpumask & CPUS{$ISOL_CPUS}" \ -e "ipi_send_cpu" -f "cpu & CPUS{$ISOL_CPUS}" \ rteval --onlyload --loads-cpulist=$HK_CPUS \ --hackbench-runlowmem=True --duration=$DURATION This only records IPIs sent to isolated CPUs, so any event there is interference (with a bit of fuzz at the start/end of the workload when spawning the processes). All tests were done with a duration of 6 hours. v6.13-rc6 # This is the actual IPI count $ trace-cmd report | grep callback | awk '{ print $(NF) }' | sort | uniq -c | sort -nr 531 callback=generic_smp_call_function_single_interrupt+0x0 # These are the different CSD's that caused IPIs $ trace-cmd report | grep csd_queue | awk '{ print $(NF-1) }' | sort | uniq -c | sort -nr 12818 func=do_flush_tlb_all 910 func=do_kernel_range_flush 78 func=do_sync_core v6.13-rc6 + patches: # This is the actual IPI count $ trace-cmd report | grep callback | awk '{ print $(NF) }' | sort | uniq -c | sort -nr # Zilch! # These are the different CSD's that caused IPIs $ trace-cmd report | grep csd_queue | awk '{ print $(NF-1) }' | sort | uniq -c | sort -nr # Nada! Note that tlb_remove_table_smp_sync() showed up during testing of v3, and has gone as mysteriously as it showed up. Yair had a series adressing this [5] which would be worth revisiting. Acknowledgements ================ Special thanks to: o Clark Williams for listening to my ramblings about this and throwing ideas my way o Josh Poimboeuf for all his help with everything objtool-related o All of the folks who attended various (too many?) talks about this and provided precious feedback. Links ===== [1]: https://lore.kernel.org/all/20210929151723.162004989@infradead.org/ [2]: https://github.com/vianpl/linux.git -b ct-work-defer-wip [3]: https://youtu.be/0vjE6fjoVVE [4]: https://lpc.events/event/18/contributions/1889/ [5]: https://lore.kernel.org/lkml/20230620144618.125703-1-ypodemsk@redhat.com/ Revisions ========= RFCv3 -> v4 ++++++++++++++ o Rebased onto v6.13-rc6 o New objtool patches from Josh o More .noinstr static key/call patches o Static calls now handled as well (again thanks to Josh) o Fixed clearing the work bits on kernel exit o Messed with IRQ hitting an idle CPU vs context tracking o Various comment and naming cleanups o Made RCU_DYNTICKS_TORTURE depend on !COMPILE_TEST (PeterZ) o Fixed the CT_STATE_KERNEL check when setting a deferred work (Frederic) o Cleaned up the __flush_tlb_all() mess thanks to PeterZ RFCv2 -> RFCv3 ++++++++++++++ o Rebased onto v6.12-rc6 o Added objtool documentation for the new warning (Josh) o Added low-size RCU watching counter to TREE04 torture scenario (Paul) o Added FORCEFUL jump label and static key types o Added noinstr-compliant helpers for tlb flush deferral RFCv1 -> RFCv2 ++++++++++++++ o Rebased onto v6.5-rc1 o Updated the trace filter patches (Steven) o Fixed __ro_after_init keys used in modules (Peter) o Dropped the extra context_tracking atomic, squashed the new bits in the existing .state field (Peter, Frederic) o Added an RCU_EXPERT config for the RCU dynticks counter size, and added an rcutorture case for a low-size counter (Paul) o Fixed flush_tlb_kernel_range_deferrable() definition Josh Poimboeuf (3): jump_label: Add annotations for validating noinstr usage static_call: Add read-only-after-init static calls objtool: Add noinstr validation for static branches/calls Peter Zijlstra (1): x86,tlb: Make __flush_tlb_global() noinstr-compliant Valentin Schneider (26): objtool: Make validate_call() recognize indirect calls to pv_ops[] objtool: Flesh out warning related to pv_ops[] calls rcu: Add a small-width RCU watching counter debug option rcutorture: Make TREE04 use CONFIG_RCU_DYNTICKS_TORTURE x86/paravirt: Mark pv_sched_clock static call as __ro_after_init x86/idle: Mark x86_idle static call as __ro_after_init x86/paravirt: Mark pv_steal_clock static call as __ro_after_init riscv/paravirt: Mark pv_steal_clock static call as __ro_after_init loongarch/paravirt: Mark pv_steal_clock static call as __ro_after_init arm64/paravirt: Mark pv_steal_clock static call as __ro_after_init arm/paravirt: Mark pv_steal_clock static call as __ro_after_init perf/x86/amd: Mark perf_lopwr_cb static call as __ro_after_init sched/clock: Mark sched_clock_running key as __ro_after_init x86/speculation/mds: Mark mds_idle_clear key as allowed in .noinstr sched/clock, x86: Mark __sched_clock_stable key as allowed in .noinstr x86/kvm/vmx: Mark vmx_l1d_should flush and vmx_l1d_flush_cond keys as allowed in .noinstr stackleack: Mark stack_erasing_bypass key as allowed in .noinstr context_tracking: Explicitely use CT_STATE_KERNEL where it is missing context_tracking: Exit CT_STATE_IDLE upon irq/nmi entry context_tracking: Turn CT_STATE_* into bits context-tracking: Introduce work deferral infrastructure context_tracking,x86: Defer kernel text patching IPIs x86/tlb: Make __flush_tlb_local() noinstr-compliant x86/tlb: Make __flush_tlb_all() noinstr x86/mm, mm/vmalloc: Defer flush_tlb_kernel_range() targeting NOHZ_FULL CPUs context-tracking: Add a Kconfig to enable IPI deferral for NO_HZ_IDLE arch/Kconfig | 9 ++ arch/arm/kernel/paravirt.c | 2 +- arch/arm64/kernel/paravirt.c | 2 +- arch/loongarch/kernel/paravirt.c | 2 +- arch/riscv/kernel/paravirt.c | 2 +- arch/x86/Kconfig | 1 + arch/x86/events/amd/brs.c | 2 +- arch/x86/include/asm/context_tracking_work.h | 22 ++++ arch/x86/include/asm/invpcid.h | 13 +-- arch/x86/include/asm/paravirt.h | 4 +- arch/x86/include/asm/text-patching.h | 1 + arch/x86/include/asm/tlbflush.h | 3 +- arch/x86/include/asm/xen/hypercall.h | 11 +- arch/x86/kernel/alternative.c | 38 ++++++- arch/x86/kernel/cpu/bugs.c | 9 +- arch/x86/kernel/kprobes/core.c | 4 +- arch/x86/kernel/kprobes/opt.c | 4 +- arch/x86/kernel/module.c | 2 +- arch/x86/kernel/paravirt.c | 4 +- arch/x86/kernel/process.c | 2 +- arch/x86/kvm/vmx/vmx.c | 11 +- arch/x86/mm/tlb.c | 46 ++++++-- arch/x86/xen/mmu_pv.c | 10 +- arch/x86/xen/xen-ops.h | 12 +- include/asm-generic/sections.h | 15 +++ include/linux/context_tracking.h | 21 ++++ include/linux/context_tracking_state.h | 64 +++++++++-- include/linux/context_tracking_work.h | 28 +++++ include/linux/jump_label.h | 30 ++++- include/linux/objtool.h | 7 ++ include/linux/static_call.h | 19 ++++ kernel/context_tracking.c | 98 ++++++++++++++-- kernel/rcu/Kconfig.debug | 15 +++ kernel/sched/clock.c | 7 +- kernel/stackleak.c | 6 +- kernel/time/Kconfig | 19 ++++ mm/vmalloc.c | 35 +++++- tools/objtool/Documentation/objtool.txt | 34 ++++++ tools/objtool/check.c | 106 +++++++++++++++--- tools/objtool/include/objtool/check.h | 1 + tools/objtool/include/objtool/elf.h | 1 + tools/objtool/include/objtool/special.h | 1 + tools/objtool/special.c | 18 ++- .../selftests/rcutorture/configs/rcu/TREE04 | 1 + 44 files changed, 635 insertions(+), 107 deletions(-) create mode 100644 arch/x86/include/asm/context_tracking_work.h create mode 100644 include/linux/context_tracking_work.h -- 2.43.0

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[PATCHv4 RESEND net-next 0/2] selftests: wireguards: use nftables for testing

by Hangbin Liu

This patch set convert iptables to nftables for wireguard testing, as iptables is deparated and nftables is the default framework of most releases. v3: drop iptables directly (Jason A. Donenfeld) Also convert to using nft for qemu testing (Jason A. Donenfeld) v2: use one nft table for testing (Phil Sutter) Hangbin Liu (2): selftests: wireguards: convert iptables to nft selftests: wireguard: update to using nft for qemu test tools/testing/selftests/wireguard/netns.sh | 29 +++++++++----- .../testing/selftests/wireguard/qemu/Makefile | 40 ++++++++++++++----- .../selftests/wireguard/qemu/kernel.config | 7 ++-- 3 files changed, 53 insertions(+), 23 deletions(-) -- 2.46.0

2 months

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Linux-kselftest-mirror January 2025