May 2025 - Linux-kselftest-mirror

[PATCH] selftests: ir_decoder: Convert header comment to proper multi-line block

by Abdelrahman Fekry

The test file for the IR decoder used single-line comments at the top to document its purpose and licensing, which is inconsistent with the style used throughout the Linux kernel. in this patch i converted the file header to a proper multi-line comment block (/*) that aligns with standard kernel practices. This improves readability, consistency across selftests, and ensures the license and documentation are clearly visible in a familiar format. No functional changes have been made. Signed-off-by: Abdelrahman Fekry <Abdelrahmanfekry375(a)gmail.com> --- tools/testing/selftests/ir/ir_loopback.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/ir/ir_loopback.c b/tools/testing/selftests/ir/ir_loopback.c index f4a15cbdd5ea..2de4a6296f35 100644 --- a/tools/testing/selftests/ir/ir_loopback.c +++ b/tools/testing/selftests/ir/ir_loopback.c @@ -1,14 +1,15 @@ // SPDX-License-Identifier: GPL-2.0 -// test ir decoder -// -// Copyright (C) 2018 Sean Young <sean(a)mess.org> - -// When sending LIRC_MODE_SCANCODE, the IR will be encoded. rc-loopback -// will send this IR to the receiver side, where we try to read the decoded -// IR. Decoding happens in a separate kernel thread, so we will need to -// wait until that is scheduled, hence we use poll to check for read -// readiness. - +/* Copyright (C) 2018 Sean Young <sean(a)mess.org> + * + * Selftest for IR decoder + * + * + * When sending LIRC_MODE_SCANCODE, the IR will be encoded. rc-loopback + * will send this IR to the receiver side, where we try to read the decoded + * IR. Decoding happens in a separate kernel thread, so we will need to + * wait until that is scheduled, hence we use poll to check for read + * readiness. +*/ #include <linux/lirc.h> #include <errno.h> #include <stdio.h> -- 2.25.1

1 week, 1 day

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[PATCH] selftests: acct: fix grammar and clarify output messages

by Abdelrahman Fekry

This patch improves the clarity and grammar of output messages in the acct() selftest. Minor changes were made to user-facing strings and comments to make them easier to understand and more consistent with the kselftest style. Changes include: - Fixing grammar in printed messages and comments. - Rewording error and success outputs for clarity and professionalism. - Making the "root check" message more direct. These updates improve readability without affecting test logic or behavior. Signed-off-by: Abdelrahman Fekry <Abdelrahmanfekry375(a)gmail.com> --- tools/testing/selftests/acct/acct_syscall.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/acct/acct_syscall.c b/tools/testing/selftests/acct/acct_syscall.c index 87c044fb9293..2c120a527574 100644 --- a/tools/testing/selftests/acct/acct_syscall.c +++ b/tools/testing/selftests/acct/acct_syscall.c @@ -22,9 +22,9 @@ int main(void) ksft_print_header(); ksft_set_plan(1); - // Check if test is run a root + // Check if test is run as root if (geteuid()) { - ksft_exit_skip("This test needs root to run!\n"); + ksft_exit_skip("This test must be run as root!\n"); return 1; } @@ -52,7 +52,7 @@ int main(void) child_pid = fork(); if (child_pid < 0) { - ksft_test_result_error("Creating a child process to log failed\n"); + ksft_test_result_error("Failed to create child process for logging\n"); acct(NULL); return 1; } else if (child_pid > 0) { -- 2.25.1

1 week, 1 day

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[PATCH] selftests: size: fix grammar and align output formatting

by Abdelrahman Fekry

Improve the grammar in the test name by changing "get runtime memory use" to "get runtime memory usage". Also adjust spacing in output lines ("Total:", "Free:", etc.) to ensure consistent alignment and readability. Signed-off-by: Abdelrahman Fekry <AbdelrahmanFekry375(a)gmail.com> --- tools/testing/selftests/size/get_size.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/size/get_size.c b/tools/testing/selftests/size/get_size.c index 2980b1a63366..d5b67c073d8e 100644 --- a/tools/testing/selftests/size/get_size.c +++ b/tools/testing/selftests/size/get_size.c @@ -86,7 +86,7 @@ void _start(void) int ccode; struct sysinfo info; unsigned long used; - static const char *test_name = " get runtime memory use\n"; + static const char *test_name = " get runtime memory usage\n"; print("TAP version 13\n"); print("# Testing system size.\n"); @@ -105,8 +105,8 @@ void _start(void) used = info.totalram - info.freeram - info.bufferram; print("# System runtime memory report (units in Kilobytes):\n"); print(" ---\n"); - print_k_value(" Total: ", info.totalram, info.mem_unit); - print_k_value(" Free: ", info.freeram, info.mem_unit); + print_k_value(" Total : ", info.totalram, info.mem_unit); + print_k_value(" Free : ", info.freeram, info.mem_unit); print_k_value(" Buffer: ", info.bufferram, info.mem_unit); print_k_value(" In use: ", used, info.mem_unit); print(" ...\n"); -- 2.25.1

1 week, 1 day

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[PATCH] selftests: size: fix grammar and align output formatting

by Abdelrahman Fekry

Improve the grammar in the test name by changing "get runtime memory use" to "get runtime memory usage". Also adjust spacing in output lines ("Total:", "Free:", etc.) to ensure consistent alignment and readability. Signed-off-by: Abdelrahman Fekry <AbdelrahmanFekry375(a)gmail.com> --- tools/testing/selftests/size/get_size.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/size/get_size.c b/tools/testing/selftests/size/get_size.c index 2980b1a63366..d5b67c073d8e 100644 --- a/tools/testing/selftests/size/get_size.c +++ b/tools/testing/selftests/size/get_size.c @@ -86,7 +86,7 @@ void _start(void) int ccode; struct sysinfo info; unsigned long used; - static const char *test_name = " get runtime memory use\n"; + static const char *test_name = " get runtime memory usage\n"; print("TAP version 13\n"); print("# Testing system size.\n"); @@ -105,8 +105,8 @@ void _start(void) used = info.totalram - info.freeram - info.bufferram; print("# System runtime memory report (units in Kilobytes):\n"); print(" ---\n"); - print_k_value(" Total: ", info.totalram, info.mem_unit); - print_k_value(" Free: ", info.freeram, info.mem_unit); + print_k_value(" Total : ", info.totalram, info.mem_unit); + print_k_value(" Free : ", info.freeram, info.mem_unit); print_k_value(" Buffer: ", info.bufferram, info.mem_unit); print_k_value(" In use: ", used, info.mem_unit); print(" ...\n"); -- 2.25.1

1 week, 1 day

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[PATCH] Fix typo in 'limit' for bpf test

by Thomas Thelen

Signed-off-by: Thomas Thelen <tommythelen(a)gmail.com> --- tools/testing/selftests/bpf/bench.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/bench.c b/tools/testing/selftests/bpf/bench.c index 1bd403a5ef7b..b25db4142126 100644 --- a/tools/testing/selftests/bpf/bench.c +++ b/tools/testing/selftests/bpf/bench.c @@ -497,7 +497,7 @@ extern const struct bench bench_rename_rawtp; extern const struct bench bench_rename_fentry; extern const struct bench bench_rename_fexit; -/* pure counting benchmarks to establish theoretical lmits */ +/* pure counting benchmarks to establish theoretical limits */ extern const struct bench bench_trig_usermode_count; extern const struct bench bench_trig_syscall_count; extern const struct bench bench_trig_kernel_count; -- 2.48.1

1 week, 1 day

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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

1 week, 1 day

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[PATCH] selftests/eventfd: correct test name and improve messages

by Ryan Chung

- Rename test from to - Make the RDWR‐flag comment declarative: “The kernel automatically adds the O_RDWR flag.” - Update semaphore‐flag failure message to: “eventfd semaphore flag check failed: …” Signed-off-by: Ryan Chung <seokwoo.chung130(a)gmail.com> --- tools/testing/selftests/filesystems/eventfd/eventfd_test.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/filesystems/eventfd/eventfd_test.c b/tools/testing/selftests/filesystems/eventfd/eventfd_test.c index 85acb4e3ef00..72d51ad0ee0e 100644 --- a/tools/testing/selftests/filesystems/eventfd/eventfd_test.c +++ b/tools/testing/selftests/filesystems/eventfd/eventfd_test.c @@ -50,7 +50,7 @@ TEST(eventfd_check_flag_rdwr) ASSERT_GE(fd, 0); flags = fcntl(fd, F_GETFL); - // since the kernel automatically added O_RDWR. + // The kernel automatically adds the O_RDWR flag. EXPECT_EQ(flags, O_RDWR); close(fd); @@ -85,7 +85,7 @@ TEST(eventfd_check_flag_nonblock) close(fd); } -TEST(eventfd_chek_flag_cloexec_and_nonblock) +TEST(eventfd_check_flag_cloexec_and_nonblock) { int fd, flags; @@ -178,8 +178,7 @@ TEST(eventfd_check_flag_semaphore) // The semaphore could only be obtained from fdinfo. ret = verify_fdinfo(fd, &err, "eventfd-semaphore: ", 19, "1\n"); if (ret != 0) - ksft_print_msg("eventfd-semaphore check failed, msg: %s\n", - err.msg); + ksft_print_msg("eventfd semaphore flag check failed: %s\n", err.msg); EXPECT_EQ(ret, 0); close(fd); -- 2.43.0

1 week, 1 day

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[PATCH] selftests: fix "memebers" typo in filesystems/mount-notify

by Hendrik Hamerlinck

Corrects a spelling mistake "memebers" instead of "members" in tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c Signed-off-by: Hendrik Hamerlinck <hendrik.hamerlinck(a)hammernet.be> --- .../selftests/filesystems/mount-notify/mount-notify_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c index 59a71f22fb11..af2b61224a61 100644 --- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c +++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c @@ -230,7 +230,7 @@ static void verify_mount_ids(struct __test_metadata *const _metadata, } } } - // Check that all list1 memebers can be found in list2. Together with + // Check that all list1 members can be found in list2. Together with // the above it means that the list1 and list2 represent the same sets. for (i = 0; i < num; i++) { for (j = 0; j < num; j++) { -- 2.43.0

1 week, 1 day

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[PATCH] selftests: Suppress unused variable warning

by Chen Linxuan

When running `make kselftest`, the following compilation warning was encountered: mount-notify_test.c: In function ‘fanotify_rmdir’: mount-notify_test.c:490:17: warning: ignoring return value of ‘chdir’ declared with attribute ‘warn_unused_result’ [-Wunused-result] 490 | chdir("/"); | ^~~~~~~~~~ This patch addresses the warning by explicitly suppressing the unused result of the `chdir` function. Signed-off-by: Chen Linxuan <chenlinxuan(a)uniontech.com> --- .../selftests/filesystems/mount-notify/mount-notify_test.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c index 59a71f22fb118..de847e2b12017 100644 --- a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c +++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c @@ -487,7 +487,9 @@ TEST_F(fanotify, rmdir) ASSERT_GE(ret, 0); if (ret == 0) { - chdir("/"); + // Suppress -Wunused-result + // Ref: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66425#c34 + (void) !chdir("/"); unshare(CLONE_NEWNS); mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL); umount2("/a", MNT_DETACH); -- 2.43.0

1 week, 2 days

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[PATCH net-next v14 0/9] Device memory TCP TX

by Mina Almasry

v14: https://lore.kernel.org/netdev/20250429032645.363766-1-almasrymina@google.c… === Picked up acks from Paolo, and addressed feedback from Paolo and Jakub. Changelog: - Fix issue in patch 4 where sockc_valid == false but err is overwritten. - Addressed nits. v13: https://lore.kernel.org/netdev/20250425204743.617260-1-almasrymina@google.c… === Changelog: - Fix unneeded error label pointed out by Christoph, and addressed nitpick. v12: https://lore.kernel.org/netdev/20250423031117.907681-1-almasrymina@google.c… ==== No changes in v12, just restored the selftests patch I accidentally dropped in v11 v11: https://lore.kernel.org/netdev/20250423031117.907681-1-almasrymina@google.c… ==== Addressed a couple of nits and collected Acked-by from Harshitha (thanks!) v10: https://lore.kernel.org/netdev/20250417231540.2780723-1-almasrymina@google.… ==== Addressed comments following conversations with Pavel, Stan, and Harshitha. Thank you guys for the reviews again. Overall minor changes: Changelog: - Check for !niov->pp in io_zcrx_recv_frag, just in case we end up with a TX niov in that path (Pavel). - Fix locking case in !netif_device_present (Jakub/Stan). v9: https://lore.kernel.org/netdev/20250415224756.152002-1-almasrymina@google.c… === Changelog: - Use priv->bindings list instead of sock_bindings_list. This was missed during the rebase as the bindings have been updated to use priv->bindings recently (thanks Stan!) v8: https://lore.kernel.org/netdev/20250308214045.1160445-1-almasrymina@google.… === Only address minor comments on V7 Changelog: - Use netdev locking instead of rtnl_locking to match rx path. - Now that iouring zcrx is in net-next, use NET_IOV_IOURING instead of NET_IOV_UNSPECIFIED. - Post send binding to net_devmem_dmabuf_bindings after it's been fully initialized (Stan). v7: https://lore.kernel.org/netdev/20250227041209.2031104-1-almasrymina@google.… === Changelog: - Check the dmabuf net_iov binding belongs to the device the TX is going out on. (Jakub) - Provide detailed inspection of callsites of __skb_frag_ref/skb_page_unref in patch 2's changelog (Jakub) v6: https://lore.kernel.org/netdev/20250222191517.743530-1-almasrymina@google.c… === v6 has no major changes. Addressed a few issues from Paolo and David, and collected Acks from Stan. Thank you everyone for the review! Changes: - retain behavior to process MSG_FASTOPEN even if the provided cmsg is invalid (Paolo). - Rework the freeing of tx_vec slightly (it now has its own err label). (Paolo). - Squash the commit that makes dmabuf unbinding scheduled work into the same one which implements the TX path so we don't run into future errors on bisecting (Paolo). - Fix/add comments to explain how dmabuf binding refcounting works (David). v5: https://lore.kernel.org/netdev/20250220020914.895431-1-almasrymina@google.c… === v5 has no major changes; it clears up the relatively minor issues pointed out to in v4, and rebases the series on top of net-next to resolve the conflict with a patch that raced to the tree. It also collects the review tags from v4. Changes: - Rebase to net-next - Fix issues in selftest (Stan). - Address comments in the devmem and netmem driver docs (Stan and Bagas) - Fix zerocopy_fill_skb_from_devmem return error code (Stan). v4: https://lore.kernel.org/netdev/20250203223916.1064540-1-almasrymina@google.… === v4 mainly addresses the critical driver support issue surfaced in v3 by Paolo and Stan. Drivers aiming to support netmem_tx should make sure not to pass the netmem dma-addrs to the dma-mapping APIs, as these dma-addrs may come from dma-bufs. Additionally other feedback from v3 is addressed. Major changes: - Add helpers to handle netmem dma-addrs. Add GVE support for netmem_tx. - Fix binding->tx_vec not being freed on error paths during the tx binding. - Add a minimal devmem_tx test to devmem.py. - Clean up everything obsolete from the cover letter (Paolo). v3: https://patchwork.kernel.org/project/netdevbpf/list/?series=929401&state=* === Address minor comments from RFCv2 and fix a few build warnings and ynl-regen issues. No major changes. RFC v2: https://patchwork.kernel.org/project/netdevbpf/list/?series=920056&state=* ======= RFC v2 addresses much of the feedback from RFC v1. I plan on sending something close to this as net-next reopens, sending it slightly early to get feedback if any. Major changes: -------------- - much improved UAPI as suggested by Stan. We now interpret the iov_base of the passed in iov from userspace as the offset into the dmabuf to send from. This removes the need to set iov.iov_base = NULL which may be confusing to users, and enables us to send multiple iovs in the same sendmsg() call. ncdevmem and the docs show a sample use of that. - Removed the duplicate dmabuf iov_iter in binding->iov_iter. I think this is good improvment as it was confusing to keep track of 2 iterators for the same sendmsg, and mistracking both iterators caused a couple of bugs reported in the last iteration that are now resolved with this streamlining. - Improved test coverage in ncdevmem. Now multiple sendmsg() are tested, and sending multiple iovs in the same sendmsg() is tested. - Fixed issue where dmabuf unmapping was happening in invalid context (Stan). ==================================================================== The TX path had been dropped from the Device Memory TCP patch series post RFCv1 [1], to make that series slightly easier to review. This series rebases the implementation of the TX path on top of the net_iov/netmem framework agreed upon and merged. The motivation for the feature is thoroughly described in the docs & cover letter of the original proposal, so I don't repeat the lengthy descriptions here, but they are available in [1]. Full outline on usage of the TX path is detailed in the documentation included with this series. Test example is available via the kselftest included in the series as well. The series is relatively small, as the TX path for this feature largely piggybacks on the existing MSG_ZEROCOPY implementation. Patch Overview: --------------- 1. Documentation & tests to give high level overview of the feature being added. 1. Add netmem refcounting needed for the TX path. 2. Devmem TX netlink API. 3. Devmem TX net stack implementation. 4. Make dma-buf unbinding scheduled work to handle TX cases where it gets freed from contexts where we can't sleep. 5. Add devmem TX documentation. 6. Add scaffolding enabling driver support for netmem_tx. Add helpers, driver feature flag, and docs to enable drivers to declare netmem_tx support. 7. Guard netmem_tx against being enabled against drivers that don't support it. 8. Add devmem_tx selftests. Add TX path to ncdevmem and add a test to devmem.py. Testing: -------- Testing is very similar to devmem TCP RX path. The ncdevmem test used for the RX path is now augemented with client functionality to test TX path. * Test Setup: Kernel: net-next with this RFC and memory provider API cherry-picked locally. Hardware: Google Cloud A3 VMs. NIC: GVE with header split & RSS & flow steering support. Performance results are not included with this version, unfortunately. I'm having issues running the dma-buf exporter driver against the upstream kernel on my test setup. The issues are specific to that dma-buf exporter and do not affect this patch series. I plan to follow up this series with perf fixes if the tests point to issues once they're up and running. Special thanks to Stan who took a stab at rebasing the TX implementation on top of the netmem/net_iov framework merged. Parts of his proposal [2] that are reused as-is are forked off into their own patches to give full credit. [1] https://lore.kernel.org/netdev/20240909054318.1809580-1-almasrymina@google.… [2] https://lore.kernel.org/netdev/20240913150913.1280238-2-sdf@fomichev.me/T/#… Cc: sdf(a)fomichev.me Cc: asml.silence(a)gmail.com Cc: dw(a)davidwei.uk Cc: Jamal Hadi Salim <jhs(a)mojatatu.com> Cc: Victor Nogueira <victor(a)mojatatu.com> Cc: Pedro Tammela <pctammela(a)mojatatu.com> Cc: Samiullah Khawaja <skhawaja(a)google.com> Cc: Kuniyuki Iwashima <kuniyu(a)amazon.com> Mina Almasry (8): netmem: add niov->type attribute to distinguish different net_iov types net: add get_netmem/put_netmem support net: devmem: Implement TX path net: add devmem TCP TX documentation net: enable driver support for netmem TX gve: add netmem TX support to GVE DQO-RDA mode net: check for driver support in netmem TX selftests: ncdevmem: Implement devmem TCP TX Stanislav Fomichev (1): net: devmem: TCP tx netlink api Documentation/netlink/specs/netdev.yaml | 12 + Documentation/networking/devmem.rst | 150 ++++++++- .../networking/net_cachelines/net_device.rst | 1 + Documentation/networking/netdev-features.rst | 5 + Documentation/networking/netmem.rst | 23 +- drivers/net/ethernet/google/gve/gve_main.c | 3 + drivers/net/ethernet/google/gve/gve_tx_dqo.c | 8 +- include/linux/netdevice.h | 2 + include/linux/skbuff.h | 17 +- include/linux/skbuff_ref.h | 4 +- include/net/netmem.h | 34 +- include/net/sock.h | 1 + include/uapi/linux/netdev.h | 1 + io_uring/zcrx.c | 3 +- net/core/datagram.c | 48 ++- net/core/dev.c | 34 +- net/core/devmem.c | 131 ++++++-- net/core/devmem.h | 83 ++++- net/core/netdev-genl-gen.c | 13 + net/core/netdev-genl-gen.h | 1 + net/core/netdev-genl.c | 80 ++++- net/core/skbuff.c | 48 ++- net/core/sock.c | 5 + net/ipv4/ip_output.c | 3 +- net/ipv4/tcp.c | 48 ++- net/ipv6/ip6_output.c | 3 +- net/vmw_vsock/virtio_transport_common.c | 5 +- tools/include/uapi/linux/netdev.h | 1 + .../selftests/drivers/net/hw/devmem.py | 26 +- .../selftests/drivers/net/hw/ncdevmem.c | 300 +++++++++++++++++- 30 files changed, 1007 insertions(+), 86 deletions(-) base-commit: 3e52667a9c328b3d1a1ddbbb6b8fbf63a217bda3 -- 2.49.0.987.g0cc8ee98dc-goog

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