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[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

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[PATCH net-next v4 0/3] Fix netdevim to correctly mark NAPI IDs

by Joe Damato

Greetings: Welcome to v4. This series fixes netdevsim to correctly set the NAPI ID on the skb. This is helpful for writing tests around features that use SO_INCOMING_NAPI_ID. In addition to the netdevsim fix in patch 1, patches 2 & 3 do some self test refactoring and add a test for NAPI IDs. The test itself (patch 3) introduces a C helper because apparently python doesn't have socket.SO_INCOMING_NAPI_ID. Thanks, Joe v4: - Updated the macro guard in patch 2 - Removed the remote deploy from patch 3 v3: https://lore.kernel.org/netdev/20250418013719.12094-1-jdamato@fastly.com/ - Dropped patch 3 from v2 as it is no longer necessary. - Patch 3 from this series (which was patch 4 in the v2) - Sorted .gitignore alphabetically - added cfg.remote_deploy so the test supports real remote machines - Dropped the NetNSEnter as it is unnecessary - Fixed a string interpolation issue that Paolo hit with his Python version v2: https://lore.kernel.org/netdev/20250417013301.39228-1-jdamato@fastly.com/ - No longer an RFC - Minor whitespace change in patch 1 (no functional change). - Patches 2-4 new in v2 rfcv1: https://lore.kernel.org/netdev/20250329000030.39543-1-jdamato@fastly.com/ Joe Damato (3): netdevsim: Mark NAPI ID on skb in nsim_rcv selftests: drv-net: Factor out ksft C helpers selftests: drv-net: Test that NAPI ID is non-zero drivers/net/netdevsim/netdev.c | 2 + .../testing/selftests/drivers/net/.gitignore | 1 + tools/testing/selftests/drivers/net/Makefile | 6 +- tools/testing/selftests/drivers/net/ksft.h | 56 +++++++++++++ .../testing/selftests/drivers/net/napi_id.py | 23 +++++ .../selftests/drivers/net/napi_id_helper.c | 83 +++++++++++++++++++ .../selftests/drivers/net/xdp_helper.c | 49 +---------- 7 files changed, 172 insertions(+), 48 deletions(-) create mode 100644 tools/testing/selftests/drivers/net/ksft.h create mode 100755 tools/testing/selftests/drivers/net/napi_id.py create mode 100644 tools/testing/selftests/drivers/net/napi_id_helper.c base-commit: cd7276ecac9c64c80433fbcff2e35aceaea6f477 -- 2.43.0

2 hours, 40 minutes

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[PATCH net 1/2] net/devmem: Reject insufficiently large dmabuf pools

by Cosmin Ratiu

Drivers that are told to allocate RX buffers from pools of DMA memory should have enough memory in the pool to satisfy projected allocation requests (a function of ring size, MTU & other parameters). If there's not enough memory, RX ring refill might fail later at inconvenient times (e.g. during NAPI poll). This commit adds a check at dmabuf pool init time that compares the amount of memory in the underlying chunk pool (configured by the user space application providing dmabuf memory) with the desired pool size (previously set by the driver) and fails with an error message if chunk memory isn't enough. Fixes: 0f9214046893 ("memory-provider: dmabuf devmem memory provider") Signed-off-by: Cosmin Ratiu <cratiu(a)nvidia.com> --- net/core/devmem.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/net/core/devmem.c b/net/core/devmem.c index 6e27a47d0493..651cd55ebb28 100644 --- a/net/core/devmem.c +++ b/net/core/devmem.c @@ -299,6 +299,7 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd, int mp_dmabuf_devmem_init(struct page_pool *pool) { struct net_devmem_dmabuf_binding *binding = pool->mp_priv; + size_t size; if (!binding) return -EINVAL; @@ -312,6 +313,16 @@ int mp_dmabuf_devmem_init(struct page_pool *pool) if (pool->p.order != 0) return -E2BIG; + /* Validate that the underlying dmabuf has enough memory to satisfy + * requested pool size. + */ + size = gen_pool_size(binding->chunk_pool) >> PAGE_SHIFT; + if (size < pool->p.pool_size) { + pr_warn("%s: Insufficient dmabuf memory (%zu pages) to satisfy pool_size (%u pages)\n", + __func__, size, pool->p.pool_size); + return -ENOMEM; + } + net_devmem_dmabuf_binding_get(binding); return 0; } -- 2.45.0

3 hours, 41 minutes

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[PATCH v1] selftests: iou-zcrx: Get the page size at runtime

by Haiyue Wang

Use the API `sysconf()` to query page size at runtime, instead of using hard code number 4096. And use `posix_memalign` to allocate the page size aligned momory. Signed-off-by: Haiyue Wang <haiyuewa(a)163.com> --- .../selftests/drivers/net/hw/iou-zcrx.c | 23 ++++++++++++------- 1 file changed, 15 insertions(+), 8 deletions(-) diff --git a/tools/testing/selftests/drivers/net/hw/iou-zcrx.c b/tools/testing/selftests/drivers/net/hw/iou-zcrx.c index c26b4180eddd..8aa426014c87 100644 --- a/tools/testing/selftests/drivers/net/hw/iou-zcrx.c +++ b/tools/testing/selftests/drivers/net/hw/iou-zcrx.c @@ -37,8 +37,8 @@ #include <liburing.h> -#define PAGE_SIZE (4096) -#define AREA_SIZE (8192 * PAGE_SIZE) +static long page_size; +#define AREA_SIZE (8192 * page_size) #define SEND_SIZE (512 * 4096) #define min(a, b) \ ({ \ @@ -66,7 +66,7 @@ static int cfg_oneshot_recvs; static int cfg_send_size = SEND_SIZE; static struct sockaddr_in6 cfg_addr; -static char payload[SEND_SIZE] __attribute__((aligned(PAGE_SIZE))); +static char *payload; static void *area_ptr; static void *ring_ptr; static size_t ring_size; @@ -114,8 +114,8 @@ static inline size_t get_refill_ring_size(unsigned int rq_entries) ring_size = rq_entries * sizeof(struct io_uring_zcrx_rqe); /* add space for the header (head/tail/etc.) */ - ring_size += PAGE_SIZE; - return ALIGN_UP(ring_size, 4096); + ring_size += page_size; + return ALIGN_UP(ring_size, page_size); } static void setup_zcrx(struct io_uring *ring) @@ -219,7 +219,7 @@ static void process_accept(struct io_uring *ring, struct io_uring_cqe *cqe) connfd = cqe->res; if (cfg_oneshot) - add_recvzc_oneshot(ring, connfd, PAGE_SIZE); + add_recvzc_oneshot(ring, connfd, page_size); else add_recvzc(ring, connfd); } @@ -245,7 +245,7 @@ static void process_recvzc(struct io_uring *ring, struct io_uring_cqe *cqe) if (cfg_oneshot) { if (cqe->res == 0 && cqe->flags == 0 && cfg_oneshot_recvs) { - add_recvzc_oneshot(ring, connfd, PAGE_SIZE); + add_recvzc_oneshot(ring, connfd, page_size); cfg_oneshot_recvs--; } } else if (!(cqe->flags & IORING_CQE_F_MORE)) { @@ -370,7 +370,7 @@ static void usage(const char *filepath) static void parse_opts(int argc, char **argv) { - const int max_payload_len = sizeof(payload) - + const int max_payload_len = SEND_SIZE - sizeof(struct ipv6hdr) - sizeof(struct tcphdr) - 40 /* max tcp options */; @@ -443,6 +443,13 @@ int main(int argc, char **argv) const char *cfg_test = argv[argc - 1]; int i; + page_size = sysconf(_SC_PAGESIZE); + if (page_size < 0) + return 1; + + if (posix_memalign((void **)&payload, page_size, SEND_SIZE)) + return 1; + parse_opts(argc, argv); for (i = 0; i < SEND_SIZE; i++) -- 2.49.0

4 hours, 18 minutes

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[PATCH v2 security-next 0/4] Introducing Hornet LSM

by Blaise Boscaccy

This patch series introduces the Hornet LSM. The goal of Hornet is to provide a signature verification mechanism for eBPF programs. eBPF has similar requirements to that of modules when it comes to loading: find symbol addresses, fix up ELF relocations, some struct field offset handling stuff called CO-RE (compile-once run-anywhere), and some other miscellaneous bookkeeping. During eBPF program compilation, pseudo-values get written to the immediate operands of instructions. During loading, those pseudo-values get rewritten with concrete addresses or data applicable to the currently running system, e.g., a kallsyms address or an fd for a map. This needs to happen before the instructions for a bpf program are loaded into the kernel via the bpf() syscall. Unlike modules, an in-kernel loader unfortunately doesn't exist. Typically, the instruction rewriting is done dynamically in userspace via libbpf. Since the relocations and instruction modifications are happening in userspace, and their values may change depending upon the running system, this breaks known signature verification mechanisms. Light skeleton programs were introduced in order to support early loading of eBPF programs along with user-mode drivers. They utilize a separate eBPF program that can load a target eBPF program and perform all necessary relocations in-kernel without needing a working userspace. Light skeletons were mentioned as a possible path forward for signature verification. Hornet takes a simple approach to light-skeleton-based eBPF signature verification. A PKCS#7 signature of a data buffer containing the raw instructions of an eBPF program, followed by the initial values of any maps used by the program is used. A utility script is provided to parse and extract the contents of autogenerated header files created via bpftool. That payload can then be signed and appended to the light skeleton executable. Maps are frozen to prevent TOCTOU bugs where a sufficiently privileged user could rewrite map data between the calls to BPF_PROG_LOAD and BPF_PROG_RUN. Additionally, both sparse-array-based and fd_array_cnt-based map fd arrays are supported for signature verification. References: [1] https://lore.kernel.org/bpf/20220209054315.73833-1-alexei.starovoitov@gmail… [2] https://lore.kernel.org/bpf/CAADnVQ+wPK1KKZhCgb-Nnf0Xfjk8M1UpX5fnXC=cBzdEYb… Change list: - v1 -> v2 - Jargon clarification, maintainer entry and a few cosmetic fixes Revisions: - v1 https://lore.kernel.org/bpf/20250321164537.16719-1-bboscaccy@linux.microsof… Blaise Boscaccy (4): security: Hornet LSM hornet: Introduce sign-ebpf hornet: Add a light-skeleton data extactor script selftests/hornet: Add a selftest for the Hornet LSM Documentation/admin-guide/LSM/Hornet.rst | 53 +++ Documentation/admin-guide/LSM/index.rst | 1 + MAINTAINERS | 9 + crypto/asymmetric_keys/pkcs7_verify.c | 10 + include/linux/kernel_read_file.h | 1 + include/linux/verification.h | 1 + include/uapi/linux/lsm.h | 1 + scripts/Makefile | 1 + scripts/hornet/Makefile | 5 + scripts/hornet/extract-skel.sh | 29 ++ scripts/hornet/sign-ebpf.c | 411 +++++++++++++++++++ security/Kconfig | 3 +- security/Makefile | 1 + security/hornet/Kconfig | 11 + security/hornet/Makefile | 4 + security/hornet/hornet_lsm.c | 239 +++++++++++ tools/testing/selftests/Makefile | 1 + tools/testing/selftests/hornet/Makefile | 51 +++ tools/testing/selftests/hornet/loader.c | 21 + tools/testing/selftests/hornet/trivial.bpf.c | 33 ++ 20 files changed, 885 insertions(+), 1 deletion(-) create mode 100644 Documentation/admin-guide/LSM/Hornet.rst create mode 100644 scripts/hornet/Makefile create mode 100755 scripts/hornet/extract-skel.sh create mode 100644 scripts/hornet/sign-ebpf.c create mode 100644 security/hornet/Kconfig create mode 100644 security/hornet/Makefile create mode 100644 security/hornet/hornet_lsm.c create mode 100644 tools/testing/selftests/hornet/Makefile create mode 100644 tools/testing/selftests/hornet/loader.c create mode 100644 tools/testing/selftests/hornet/trivial.bpf.c -- 2.48.1

4 hours, 37 minutes

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[PATCH RFC bpf-next 0/4] bpf, arm64: support up to 12 arguments

by Alexis Lothoré (eBPF Foundation)

Hello, this series is a revival of Xu Kuhoai's work to enable larger arguments count for BPF programs on ARM64 ([1]). His initial series received some positive feedback, but lacked some specific case handling around arguments alignment (see AAPCS64 C.14 rule in section 6.8.2, [2]). There as been another attempt from Puranjay Mohan, which was unfortunately missing the same thing ([3]). Since there has been some time between those series and this new one, I chose to send it as a new series rather than a new revision of the existing series. To support the increased argument counts and arguments larger than registers size (eg: structures), the trampoline does the following: - for bpf programs: arguments are retrieved from both registers and the function stack, and pushed in the trampoline stack as an array of u64 to generate the programs context. It is then passed by pointer to the bpf programs - when the trampoline is in charge of calling the original function: it restores the registers content, and generates a new stack layout for the additional arguments that do not fit in registers. This new attempt is based on Xu's series and aims to handle the missing alignment concern raised in the reviews discussions. The main novelties are then around arguments alignments: - the first commit is exposing some new info in the BTF function model passed to the JIT compiler to allow it to deduce the needed alignment when configuring the trampoline stack - the second commit is taken from Xu's series, and received the following modifications: - the calc_aux_args computes an expected alignment for each argument - the calc_aux_args computes two different stack space sizes: the one needed to store the bpf programs context, and the original function stacked arguments (which needs alignment). Those stack sizes are in bytes instead of "slots" - when saving/restoring arguments for bpf program or for the original function, make sure to align the load/store accordingly, when relevant - a few typos fixes and some rewording, raised by the review on the original series - the last commit introduces some explicit tests that ensure that the needed alignment is enforced by the trampoline I marked the series as RFC because it appears that the new tests trigger some failures in CI on x86 and s390, despite the series not touching any code related to those architectures. Some very early investigation/gdb debugging on the x86 side seems to hint that it could be related to the same missing alignment too (based on section 3.2.3 in [4], and so the x86 trampoline would need the same alignment handling ?). For s390 it looks less clear, as all values captured from the bpf test program are set to 0 in the CI output, and I don't have the proper setup yet to check the low level details. I am tempted to isolate those new tests (which were actually useful to spot real issues while tuning the ARM64 trampoline) and add them to the relevant DENYLIST files for x86/s390, but I guess this is not the right direction, so I would gladly take a second opinion on this. [1] https://lore.kernel.org/all/20230917150752.69612-1-xukuohai@huaweicloud.com… [2] https://github.com/ARM-software/abi-aa/blob/main/aapcs64/aapcs64.rst#id82 [3] https://lore.kernel.org/bpf/20240705125336.46820-1-puranjay@kernel.org/ [4] https://refspecs.linuxbase.org/elf/x86_64-abi-0.99.pdf Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore(a)bootlin.com> --- Alexis Lothoré (eBPF Foundation) (3): bpf: add struct largest member size in func model bpf/selftests: add tests to validate proper arguments alignment on ARM64 bpf/selftests: enable tracing tests for ARM64 Xu Kuohai (1): bpf, arm64: Support up to 12 function arguments arch/arm64/net/bpf_jit_comp.c | 235 ++++++++++++++++----- include/linux/bpf.h | 1 + kernel/bpf/btf.c | 25 +++ tools/testing/selftests/bpf/DENYLIST.aarch64 | 3 - .../selftests/bpf/prog_tests/tracing_struct.c | 23 ++ tools/testing/selftests/bpf/progs/tracing_struct.c | 10 +- .../selftests/bpf/progs/tracing_struct_many_args.c | 67 ++++++ .../testing/selftests/bpf/test_kmods/bpf_testmod.c | 50 +++++ 8 files changed, 357 insertions(+), 57 deletions(-) --- base-commit: 91e7eb701b4bc389e7ddfd80ef6e82d1a6d2d368 change-id: 20250220-many_args_arm64-8bd3747e6948 Best regards, -- Alexis Lothoré, Bootlin Embedded Linux and Kernel engineering https://bootlin.com

5 hours, 4 minutes

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[PATCH 0/4] selftest: can: Start importing selftests from can-tests

by Felix Maurer

This is the initial import of a CAN selftest from can-tests[1] into the tree. For now, it is just a single test but when agreed on the structure, we intend to import more tests from can-tests and add additional test cases. The goal of moving the CAN selftests into the tree is to align the tests more closely with the kernel, improve testing of CAN in general, and to simplify running the tests automatically in the various kernel CI systems. I have cc'ed netdev and its reviewers and maintainers to make sure they are okay with the location of the tests and the changes to the paths in MAINTAINERS. The changes should be merged through linux-can-next and subsequent changes will not go to netdev anymore. [1]: https://github.com/linux-can/can-tests Felix Maurer (4): selftests: can: Import tst-filter from can-tests selftests: can: use kselftest harness in test_raw_filter selftests: can: Use fixtures in test_raw_filter selftests: can: Document test_raw_filter test cases MAINTAINERS | 2 + tools/testing/selftests/Makefile | 1 + tools/testing/selftests/net/can/.gitignore | 2 + tools/testing/selftests/net/can/Makefile | 11 + .../selftests/net/can/test_raw_filter.c | 338 ++++++++++++++++++ .../selftests/net/can/test_raw_filter.sh | 37 ++ 6 files changed, 391 insertions(+) create mode 100644 tools/testing/selftests/net/can/.gitignore create mode 100644 tools/testing/selftests/net/can/Makefile create mode 100644 tools/testing/selftests/net/can/test_raw_filter.c create mode 100755 tools/testing/selftests/net/can/test_raw_filter.sh -- 2.49.0

5 hours, 17 minutes

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[PATCH net 1/2] net: mscc: ocelot: delete PVID VLAN when readding it as non-PVID

by Vladimir Oltean

The following set of commands: ip link add br0 type bridge vlan_filtering 1 # vlan_default_pvid 1 is implicit ip link set swp0 master br0 bridge vlan add dev swp0 vid 1 should result in the dropping of untagged and 802.1p-tagged traffic, but we see that it continues to be accepted. Whereas, had we deleted VID 1 instead, the aforementioned dropping would have worked This is because the ANA_PORT_DROP_CFG update logic doesn't run, because ocelot_vlan_add() only calls ocelot_port_set_pvid() if the new VLAN has the BRIDGE_VLAN_INFO_PVID flag. Similar to other drivers like mt7530_port_vlan_add() which handle this case correctly, we need to test whether the VLAN we're changing used to have the BRIDGE_VLAN_INFO_PVID flag, but lost it now. That amounts to a PVID deletion and should be treated as such. Regarding blame attribution: this never worked properly since the introduction of bridge VLAN filtering in commit 7142529f1688 ("net: mscc: ocelot: add VLAN filtering"). However, there was a significant paradigm shift which aligned the ANA_PORT_DROP_CFG register with the PVID concept rather than with the native VLAN concept, and that change wasn't targeted for 'stable'. Realistically, that is as far as this fix needs to be propagated to. Fixes: be0576fed6d3 ("net: mscc: ocelot: move the logic to drop 802.1p traffic to the pvid deletion") Signed-off-by: Vladimir Oltean <vladimir.oltean(a)nxp.com> --- drivers/net/ethernet/mscc/ocelot.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c index ef93df520887..08bee56aea35 100644 --- a/drivers/net/ethernet/mscc/ocelot.c +++ b/drivers/net/ethernet/mscc/ocelot.c @@ -830,6 +830,7 @@ EXPORT_SYMBOL(ocelot_vlan_prepare); int ocelot_vlan_add(struct ocelot *ocelot, int port, u16 vid, bool pvid, bool untagged) { + struct ocelot_port *ocelot_port = ocelot->ports[port]; int err; /* Ignore VID 0 added to our RX filter by the 8021q module, since @@ -849,6 +850,11 @@ int ocelot_vlan_add(struct ocelot *ocelot, int port, u16 vid, bool pvid, ocelot_bridge_vlan_find(ocelot, vid)); if (err) return err; + } else if (ocelot_port->pvid_vlan && + ocelot_bridge_vlan_find(ocelot, vid) == ocelot_port->pvid_vlan) { + err = ocelot_port_set_pvid(ocelot, port, NULL); + if (err) + return err; } /* Untagged egress vlan clasification */ -- 2.43.0

5 hours, 41 minutes

1
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Call for Participation: Automated Testing Summit 2025 @ OSS NA

by Gustavo Padovan

The Automated Testing Summit (ATS) 2025 will be held as a co-located event at the Open Source Summit North America, and we’re now accepting talk proposals! https://events.linuxfoundation.org/open-source-summit-north-america/feature… 📅 Date: June 26, 2025 📍 Location: Denver, CO, USA Hosted by KernelCI, ATS is a technical summit focused on the challenges of testing and quality assurance in the Linux ecosystem — especially in upstream kernel development, embedded systems, cloud environments, and CI integration. This is a great opportunity to share your work on: * Kernel and userspace test frameworks * Lab infrastructure and automation * CI/CD pipelines for Linux * Fuzzing, performance testing, and debugging tools * Sharing and standardizing test results across systems Whether you’re working on kernel testing, running tests on hardware labs, developing QA tools, or building infrastructure that scales across projects, ATS is the place to collaborate and move the ecosystem forward. Submit your talk by May 18, 2025: 👉 Call for Proposals (CFP): https://sessionize.com/atsna2025 We hope to see you in Denver! — The KernelCI Team

7 hours, 2 minutes

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[PATCH bpf-next v2] bpf: Allow XDP dev-bound programs to perform XDP_REDIRECT into maps

by Lorenzo Bianconi

In the current implementation if the program is dev-bound to a specific device, it will not be possible to perform XDP_REDIRECT into a DEVMAP or CPUMAP even if the program is running in the driver NAPI context and it is not attached to any map entry. This seems in contrast with the explanation available in bpf_prog_map_compatible routine. Fix the issue introducing __bpf_prog_map_compatible utility routine in order to avoid bpf_prog_is_dev_bound() check running bpf_check_tail_call() at program load time (bpf_prog_select_runtime()). Continue forbidding to attach a dev-bound program to XDP maps (BPF_MAP_TYPE_PROG_ARRAY, BPF_MAP_TYPE_DEVMAP and BPF_MAP_TYPE_CPUMAP). Fixes: 3d76a4d3d4e59 ("bpf: XDP metadata RX kfuncs") Signed-off-by: Lorenzo Bianconi <lorenzo(a)kernel.org> --- Changes in v2: - Introduce __bpf_prog_map_compatible() utility routine in order to skip bpf_prog_is_dev_bound check in bpf_check_tail_call() - Extend xdp_metadata selftest - Link to v1: https://lore.kernel.org/r/20250422-xdp-prog-bound-fix-v1-1-0b581fa186fe@ker… --- kernel/bpf/core.c | 27 +++++++++++++--------- .../selftests/bpf/prog_tests/xdp_metadata.c | 22 +++++++++++++++++- tools/testing/selftests/bpf/progs/xdp_metadata.c | 13 +++++++++++ 3 files changed, 50 insertions(+), 12 deletions(-) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index ba6b6118cf504041278d05417c4212d57be6fca0..a3e571688421196c3ceaed62b3b59b62a0258a8c 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2358,8 +2358,8 @@ static unsigned int __bpf_prog_ret0_warn(const void *ctx, return 0; } -bool bpf_prog_map_compatible(struct bpf_map *map, - const struct bpf_prog *fp) +static bool __bpf_prog_map_compatible(struct bpf_map *map, + const struct bpf_prog *fp) { enum bpf_prog_type prog_type = resolve_prog_type(fp); bool ret; @@ -2368,14 +2368,6 @@ bool bpf_prog_map_compatible(struct bpf_map *map, if (fp->kprobe_override) return false; - /* XDP programs inserted into maps are not guaranteed to run on - * a particular netdev (and can run outside driver context entirely - * in the case of devmap and cpumap). Until device checks - * are implemented, prohibit adding dev-bound programs to program maps. - */ - if (bpf_prog_is_dev_bound(aux)) - return false; - spin_lock(&map->owner.lock); if (!map->owner.type) { /* There's no owner yet where we could check for @@ -2409,6 +2401,19 @@ bool bpf_prog_map_compatible(struct bpf_map *map, return ret; } +bool bpf_prog_map_compatible(struct bpf_map *map, const struct bpf_prog *fp) +{ + /* XDP programs inserted into maps are not guaranteed to run on + * a particular netdev (and can run outside driver context entirely + * in the case of devmap and cpumap). Until device checks + * are implemented, prohibit adding dev-bound programs to program maps. + */ + if (bpf_prog_is_dev_bound(fp->aux)) + return false; + + return __bpf_prog_map_compatible(map, fp); +} + static int bpf_check_tail_call(const struct bpf_prog *fp) { struct bpf_prog_aux *aux = fp->aux; @@ -2421,7 +2426,7 @@ static int bpf_check_tail_call(const struct bpf_prog *fp) if (!map_type_contains_progs(map)) continue; - if (!bpf_prog_map_compatible(map, fp)) { + if (!__bpf_prog_map_compatible(map, fp)) { ret = -EINVAL; goto out; } diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c index 3d47878ef6bfb55c236dc9df2c100fcc449f8de3..19f92affc2daa23fdd869554e7a0475b86350a4f 100644 --- a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c +++ b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c @@ -351,9 +351,10 @@ void test_xdp_metadata(void) struct xdp_metadata2 *bpf_obj2 = NULL; struct xdp_metadata *bpf_obj = NULL; struct bpf_program *new_prog, *prog; + struct bpf_devmap_val devmap_e = {}; + struct bpf_map *prog_arr, *devmap; struct nstoken *tok = NULL; __u32 queue_id = QUEUE_ID; - struct bpf_map *prog_arr; struct xsk tx_xsk = {}; struct xsk rx_xsk = {}; __u32 val, key = 0; @@ -409,6 +410,13 @@ void test_xdp_metadata(void) bpf_program__set_ifindex(prog, rx_ifindex); bpf_program__set_flags(prog, BPF_F_XDP_DEV_BOUND_ONLY); + /* Make sure we can load a dev-bound program that performs + * XDP_REDIRECT into a devmap. + */ + new_prog = bpf_object__find_program_by_name(bpf_obj->obj, "redirect"); + bpf_program__set_ifindex(new_prog, rx_ifindex); + bpf_program__set_flags(new_prog, BPF_F_XDP_DEV_BOUND_ONLY); + if (!ASSERT_OK(xdp_metadata__load(bpf_obj), "load skeleton")) goto out; @@ -423,6 +431,18 @@ void test_xdp_metadata(void) "update prog_arr")) goto out; + /* Make sure we can't add dev-bound programs to devmaps. */ + devmap = bpf_object__find_map_by_name(bpf_obj->obj, "dev_map"); + if (!ASSERT_OK_PTR(devmap, "no dev_map found")) + goto out; + + devmap_e.bpf_prog.fd = val; + if (!ASSERT_ERR(bpf_map__update_elem(devmap, &key, sizeof(key), + &devmap_e, sizeof(devmap_e), + BPF_ANY), + "update dev_map")) + goto out; + /* Attach BPF program to RX interface. */ ret = bpf_xdp_attach(rx_ifindex, diff --git a/tools/testing/selftests/bpf/progs/xdp_metadata.c b/tools/testing/selftests/bpf/progs/xdp_metadata.c index 31ca229bb3c0f182483334a4ab0bd204acae20f3..09bb8a038d528cf26c5b314cc927915ac2796bf0 100644 --- a/tools/testing/selftests/bpf/progs/xdp_metadata.c +++ b/tools/testing/selftests/bpf/progs/xdp_metadata.c @@ -19,6 +19,13 @@ struct { __type(value, __u32); } prog_arr SEC(".maps"); +struct { + __uint(type, BPF_MAP_TYPE_DEVMAP); + __uint(key_size, sizeof(__u32)); + __uint(value_size, sizeof(struct bpf_devmap_val)); + __uint(max_entries, 1); +} dev_map SEC(".maps"); + extern int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx, __u64 *timestamp) __ksym; extern int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, __u32 *hash, @@ -95,4 +102,10 @@ int rx(struct xdp_md *ctx) return bpf_redirect_map(&xsk, ctx->rx_queue_index, XDP_PASS); } +SEC("xdp") +int redirect(struct xdp_md *ctx) +{ + return bpf_redirect_map(&dev_map, ctx->rx_queue_index, XDP_PASS); +} + char _license[] SEC("license") = "GPL"; --- base-commit: 5cffad0a5c8f0cc53ce9fe7cff7bc67c3a97c406 change-id: 20250422-xdp-prog-bound-fix-9f30f3e134aa Best regards, -- Lorenzo Bianconi <lorenzo(a)kernel.org>

7 hours, 17 minutes

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