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[PATCH 0/4] Replace CONFIG_DMABUF_SYSFS_STATS with BPF

by T.J. Mercier

Until CONFIG_DMABUF_SYSFS_STATS was added [1] it was only possible to perform per-buffer accounting with debugfs which is not suitable for production environments. Eventually we discovered the overhead with per-buffer sysfs file creation/removal was significantly impacting allocation and free times, and exacerbated kernfs lock contention. [2] dma_buf_stats_setup() is responsible for 39% of single-page buffer creation duration, or 74% of single-page dma_buf_export() duration when stressing dmabuf allocations and frees. I prototyped a change from per-buffer to per-exporter statistics with a RCU protected list of exporter allocations that accommodates most (but not all) of our use-cases and avoids almost all of the sysfs overhead. While that adds less overhead than per-buffer sysfs, and less even than the maintenance of the dmabuf debugfs_list, it's still *additional* overhead on top of the debugfs_list and doesn't give us per-buffer info. This series uses the existing dmabuf debugfs_list to implement a BPF dmabuf iterator, which adds no overhead to buffer allocation/free and provides per-buffer info. While the kernel must have CONFIG_DEBUG_FS for the dmabuf_iter to be available, debugfs does not need to be mounted. The BPF program loaded by userspace that extracts per-buffer information gets to define its own interface which avoids the lack of ABI stability with debugfs (even if it were mounted). As this is a replacement for our use of CONFIG_DMABUF_SYSFS_STATS, the last patch is a RFC for removing it from the kernel. Please see my suggestion there regarding the timeline for that. [1] https://lore.kernel.org/linux-media/20201210044400.1080308-1-hridya@google.… [2] https://lore.kernel.org/all/20220516171315.2400578-1-tjmercier@google.com/ T.J. Mercier (4): dma-buf: Rename and expose debugfs symbols bpf: Add dmabuf iterator selftests/bpf: Add test for dmabuf_iter RFC: dma-buf: Remove DMA-BUF statistics .../ABI/testing/sysfs-kernel-dmabuf-buffers | 24 --- Documentation/driver-api/dma-buf.rst | 5 - drivers/dma-buf/Kconfig | 15 -- drivers/dma-buf/Makefile | 1 - drivers/dma-buf/dma-buf-sysfs-stats.c | 202 ------------------ drivers/dma-buf/dma-buf-sysfs-stats.h | 35 --- drivers/dma-buf/dma-buf.c | 40 +--- include/linux/btf_ids.h | 1 + include/linux/dma-buf.h | 6 + kernel/bpf/Makefile | 3 + kernel/bpf/dmabuf_iter.c | 130 +++++++++++ tools/testing/selftests/bpf/config | 1 + .../selftests/bpf/prog_tests/dmabuf_iter.c | 116 ++++++++++ .../testing/selftests/bpf/progs/dmabuf_iter.c | 31 +++ 14 files changed, 299 insertions(+), 311 deletions(-) delete mode 100644 Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers delete mode 100644 drivers/dma-buf/dma-buf-sysfs-stats.c delete mode 100644 drivers/dma-buf/dma-buf-sysfs-stats.h create mode 100644 kernel/bpf/dmabuf_iter.c create mode 100644 tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c create mode 100644 tools/testing/selftests/bpf/progs/dmabuf_iter.c -- 2.49.0.604.gff1f9ca942-goog

2 days, 17 hours

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Re: [PATCH v7 1/2] selftests: memcg: Allow low event with no memory.low and memory_recursiveprot on

by Michal Koutný

On Tue, Apr 22, 2025 at 07:58:56PM -0400, Waiman Long <llong(a)redhat.com> wrote: > Am I correct to assume that the purpose of 1d09069f5313f ("selftests: > memcg: expect no low events in unprotected sibling") is to force a > failure in the test_memcg_low test to force a change in the current > behavior? Or was it the case that it didn't fail when you submit your > patch? Yes, the failure had been intended to mark unexpected mode of reclaim (there's still a reproducer somewhere in the references). However, I learnt that: a) it ain't easy to fix, b) the only occurence of the troublesome behavior was in the test and never reported by users in real life. I've started to prefer the variant where the particular check is indefinite since that. HTH, Michal

2 days, 17 hours

2
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[PATCH v4 0/5] Add support for the Bus Lock Threshold

by Manali Shukla

Misbehaving guests can cause bus locks to degrade the performance of a system. Non-WB (write-back) and misaligned locked RMW (read-modify-write) instructions are referred to as "bus locks" and require system wide synchronization among all processors to guarantee the atomicity. The bus locks can impose notable performance penalties for all processors within the system. Support for the Bus Lock Threshold is indicated by CPUID Fn8000_000A_EDX[29] BusLockThreshold=1, the VMCB provides a Bus Lock Threshold enable bit and an unsigned 16-bit Bus Lock Threshold count. VMCB intercept bit VMCB Offset Bits Function 14h 5 Intercept bus lock operations Bus lock threshold count VMCB Offset Bits Function 120h 15:0 Bus lock counter During VMRUN, the bus lock threshold count is fetched and stored in an internal count register. Prior to executing a bus lock within the guest, the processor verifies the count in the bus lock register. If the count is greater than zero, the processor executes the bus lock, reducing the count. However, if the count is zero, the bus lock operation is not performed, and instead, a Bus Lock Threshold #VMEXIT is triggered to transfer control to the Virtual Machine Monitor (VMM). A Bus Lock Threshold #VMEXIT is reported to the VMM with VMEXIT code 0xA5h, VMEXIT_BUSLOCK. EXITINFO1 and EXITINFO2 are set to 0 on a VMEXIT_BUSLOCK. On a #VMEXIT, the processor writes the current value of the Bus Lock Threshold Counter to the VMCB. Note: Currently, virtualizing the Bus Lock Threshold feature for L1 guest is not supported. More details about the Bus Lock Threshold feature can be found in AMD APM [1]. v3 -> v4 - Incorporated Sean's review comments - Added a preparatory patch to move linear_rip out of kvm_pio_request, so that it can be used by the bus lock threshold patches. - Added complete_userspace_buslock() function to reload bus_lock_counter to '1' only if the usespace has not changed the RIP. - Added changes to continue running bus_lock_counter accross the nested transitions. v2 -> v3 - Drop parch to add virt tag in /proc/cpuinfo. - Incorporated Tom's review comments. v1 -> v2 - Incorporated misc review comments from Sean. - Removed bus_lock_counter module parameter. - Set the value of bus_lock_counter to zero by default and reload the value by 1 in bus lock exit handler. - Add documentation for the behavioral difference for KVM_EXIT_BUS_LOCK. - Improved selftest for buslock to work on SVM and VMX. - Rewrite the commit messages. Patches are prepared on kvm-next/next (c9ea48bb6ee6). Testing done: - Tested the Bus Lock Threshold functionality on normal, SEV, SEV-ES and SEV-SNP guests. - Tested the Bus Lock Threshold functionality on nested guests. v1: https://lore.kernel.org/kvm/20240709175145.9986-4-manali.shukla@amd.com/T/ v2: https://lore.kernel.org/kvm/20241001063413.687787-4-manali.shukla@amd.com/T/ v3: https://lore.kernel.org/kvm/20241004053341.5726-1-manali.shukla@amd.com/T/ [1]: AMD64 Architecture Programmer's Manual Pub. 24593, April 2024, Vol 2, 15.14.5 Bus Lock Threshold. https://bugzilla.kernel.org/attachment.cgi?id=306250 Manali Shukla (3): KVM: x86: Preparatory patch to move linear_rip out of kvm_pio_request x86/cpufeatures: Add CPUID feature bit for the Bus Lock Threshold KVM: SVM: Add support for KVM_CAP_X86_BUS_LOCK_EXIT on SVM CPUs Nikunj A Dadhania (2): KVM: SVM: Enable Bus lock threshold exit KVM: selftests: Add bus lock exit test Documentation/virt/kvm/api.rst | 19 +++ arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/include/asm/svm.h | 5 +- arch/x86/include/uapi/asm/svm.h | 2 + arch/x86/kvm/svm/nested.c | 42 ++++++ arch/x86/kvm/svm/svm.c | 38 +++++ arch/x86/kvm/svm/svm.h | 2 + arch/x86/kvm/x86.c | 8 +- tools/testing/selftests/kvm/Makefile.kvm | 1 + .../selftests/kvm/x86/kvm_buslock_test.c | 135 ++++++++++++++++++ 11 files changed, 249 insertions(+), 6 deletions(-) create mode 100644 tools/testing/selftests/kvm/x86/kvm_buslock_test.c base-commit: c9ea48bb6ee6b28bbc956c1e8af98044618fed5e -- 2.34.1

2 days, 18 hours

4
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[PATCH net-next v9 0/9] Device memory TCP TX

by Mina Almasry

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 | 4 + 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 | 1 + net/core/datagram.c | 48 ++- net/core/dev.c | 34 +- net/core/devmem.c | 139 ++++++-- net/core/devmem.h | 83 ++++- net/core/netdev-genl-gen.c | 13 + net/core/netdev-genl-gen.h | 1 + net/core/netdev-genl.c | 75 ++++- net/core/skbuff.c | 48 ++- net/core/sock.c | 6 + net/ipv4/ip_output.c | 3 +- net/ipv4/tcp.c | 50 ++- 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, 1009 insertions(+), 89 deletions(-) base-commit: 240ce924d2718b8f6f622f2a9a9c219b9da736e8 -- 2.49.0.805.g082f7c87e0-goog

2 days, 23 hours

3
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[PATCH net-next v2] selftests/vsock: add initial vmtest.sh for vsock

by Bobby Eshleman

This commit introduces a new vmtest.sh runner for vsock. It uses virtme-ng/qemu to run tests in a VM. The tests validate G2H, H2G, and loopback. The testing tools from tools/testing/vsock/ are reused. Currently, only vsock_test is used. VMCI and hyperv support is automatically built, though not used. Only tested on x86. To run: $ tools/testing/selftests/vsock/vmtest.sh Future work can include vsock_diag_test. Signed-off-by: Bobby Eshleman <bobbyeshleman(a)gmail.com> --- Changes in v2: - add kernel oops and warnings checker - change testname variable to use FUNCNAME - fix spacing in test_vm_server_host_client - add -s skip build option to vmtest.sh - add test_vm_loopback - pass port to vm_wait_for_listener - fix indentation in vmtest.sh - add vmci and hyperv to config - changed whitespace from tabs to spaces in help string - Link to v1: https://lore.kernel.org/r/20250410-vsock-vmtest-v1-1-f35a81dab98c@gmail.com --- MAINTAINERS | 1 + tools/testing/selftests/vsock/.gitignore | 1 + tools/testing/selftests/vsock/config.vsock | 10 + tools/testing/selftests/vsock/vmtest.sh | 306 +++++++++++++++++++++++++++++ 4 files changed, 318 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index c3fce441672349f7850c57d788bc1a29b203fba5..f214cf7c4fb59ec67885ee6c81daa44e17c80f5f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -25323,6 +25323,7 @@ F: include/uapi/linux/vm_sockets.h F: include/uapi/linux/vm_sockets_diag.h F: include/uapi/linux/vsockmon.h F: net/vmw_vsock/ +F: tools/testing/selftests/vsock/ F: tools/testing/vsock/ VMALLOC diff --git a/tools/testing/selftests/vsock/.gitignore b/tools/testing/selftests/vsock/.gitignore new file mode 100644 index 0000000000000000000000000000000000000000..1950aa8ac68c0831c12c1aaa429da45bbe41e60f --- /dev/null +++ b/tools/testing/selftests/vsock/.gitignore @@ -0,0 +1 @@ +vsock_selftests.log diff --git a/tools/testing/selftests/vsock/config.vsock b/tools/testing/selftests/vsock/config.vsock new file mode 100644 index 0000000000000000000000000000000000000000..9e0fb2270e6a2fc0beb5f0d9f0bc37158d0a9d23 --- /dev/null +++ b/tools/testing/selftests/vsock/config.vsock @@ -0,0 +1,10 @@ +CONFIG_VSOCKETS=y +CONFIG_VSOCKETS_DIAG=y +CONFIG_VSOCKETS_LOOPBACK=y +CONFIG_VMWARE_VMCI_VSOCKETS=y +CONFIG_VIRTIO_VSOCKETS=y +CONFIG_VIRTIO_VSOCKETS_COMMON=y +CONFIG_HYPERV_VSOCKETS=y +CONFIG_VMWARE_VMCI=y +CONFIG_VHOST_VSOCK=y +CONFIG_HYPERV=y diff --git a/tools/testing/selftests/vsock/vmtest.sh b/tools/testing/selftests/vsock/vmtest.sh new file mode 100755 index 0000000000000000000000000000000000000000..61dfcc06223fa7a30cb575cb3f2d01121b3ed3ce --- /dev/null +++ b/tools/testing/selftests/vsock/vmtest.sh @@ -0,0 +1,306 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# Copyright (c) 2025 Meta Platforms, Inc. and affiliates +# +# Dependencies: +# * virtme-ng +# * busybox-static (used by virtme-ng) +# * qemu (used by virtme-ng) + +SCRIPT_DIR="$(cd -P -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd -P)" +KERNEL_CHECKOUT=$(realpath ${SCRIPT_DIR}/../../../..) +PLATFORM=${PLATFORM:-$(uname -m)} + +if [[ -z "${QEMU:-}" ]]; then + QEMU=$(which qemu-system-${PLATFORM}) +fi + +SKIP_BUILD=0 + +VSOCK_TEST=${KERNEL_CHECKOUT}/tools/testing/vsock/vsock_test + +TEST_GUEST_PORT=51000 +TEST_HOST_PORT=50000 +TEST_HOST_PORT_LISTENER=50001 +SSH_GUEST_PORT=22 +SSH_HOST_PORT=2222 +VSOCK_CID=1234 + +QEMU_PIDFILE=/tmp/qemu.pid + +# virtme-ng offers a netdev for ssh when using "--ssh", but we also need a +# control port forwarded for vsock_test. Because virtme-ng doesn't support +# adding an additional port to forward to the device created from "--ssh" and +# virtme-init mistakenly sets identical IPs to the ssh device and additional +# devices, we instead opt out of using --ssh, add the device manually, and also +# add the kernel cmdline options that virtme-init uses to setup the interface. +QEMU_OPTS="" +QEMU_OPTS="${QEMU_OPTS} -netdev user,id=n0,hostfwd=tcp::${TEST_HOST_PORT}-:${TEST_GUEST_PORT}" +QEMU_OPTS="${QEMU_OPTS},hostfwd=tcp::${SSH_HOST_PORT}-:${SSH_GUEST_PORT}" +QEMU_OPTS="${QEMU_OPTS} -device virtio-net-pci,netdev=n0" +QEMU_OPTS="${QEMU_OPTS} -device vhost-vsock-pci,guest-cid=${VSOCK_CID}" +QEMU_OPTS="${QEMU_OPTS} --pidfile ${QEMU_PIDFILE}" +KERNEL_CMDLINE="virtme.dhcp net.ifnames=0 biosdevname=0 virtme.ssh virtme_ssh_user=$USER" + +LOG=${SCRIPT_DIR}/vsock_selftests.log + +# Name Description +tests=" + vm_server_host_client Run vsock_test in server mode on the VM and in client mode on the host. + vm_client_host_server Run vsock_test in client mode on the VM and in server mode on the host. + vm_loopback Run vsock_test using the loopback transport in the VM. +" + +usage() { + echo + echo "$0 [OPTIONS]" + echo + echo "Options" + echo " -v: verbose output" + echo " -s: skip build" + echo + echo "Available tests${tests}" + exit 1 +} + +die() { + echo "$*" >&2 + exit 1 +} + +vm_ssh() { + ssh -q -o UserKnownHostsFile=/dev/null -p 2222 localhost $* + return $? +} + +cleanup() { + if [[ -f "${QEMU_PIDFILE}" ]]; then + pkill -9 -F ${QEMU_PIDFILE} 2>&1 >/dev/null + fi +} + +build() { + log_setup "Building kernel and tests" + + pushd ${KERNEL_CHECKOUT} >/dev/null + vng \ + --kconfig \ + --config ${KERNEL_CHECKOUT}/tools/testing/selftests/vsock/config.vsock + make -j$(nproc) + make -C ${KERNEL_CHECKOUT}/tools/testing/vsock + popd >/dev/null + echo +} + +vm_setup() { + local VNG_OPTS="" + if [[ "${VERBOSE}" = 1 ]]; then + VNG_OPTS="--verbose" + fi + vng \ + $VNG_OPTS \ + --run ~/local/linux \ + --qemu /bin/qemu-system-x86_64 \ + --qemu-opts="${QEMU_OPTS}" \ + --user root \ + --append "${KERNEL_CMDLINE}" \ + --rw 2>&1 >/dev/null & +} + +vm_wait_for_ssh() { + i=0 + while [[ true ]]; do + if (( i > 20 )); then + die "Timed out waiting for guest ssh" + fi + vm_ssh -- true + if [[ $? -eq 0 ]]; then + break + fi + i=$(( i + 1 )) + sleep 5 + done +} + +wait_for_listener() { + local PORT=$1 + local i=0 + while ! ss -ltn | grep -q ":${PORT}"; do + if (( i > 30 )); then + die "Timed out waiting for listener on port ${PORT}" + fi + sleep 3 + i=$(( i + 1 )) + done +} + +vm_wait_for_listener() { + local port=$1 + vm_ssh -- "$(declare -f wait_for_listener); wait_for_listener ${port}" +} + +host_wait_for_listener() { + wait_for_listener ${TEST_HOST_LISTENER_PORT} +} + +log() { + local prefix="$1" + shift + + if [[ "$#" -eq 0 ]]; then + cat | awk '{ printf "%s:\t%s\n","'"${prefix}"'", $0 }' | tee -a ${LOG} + else + echo "$*" | awk '{ printf "%s:\t%s\n","'"${prefix}"'", $0 }' | tee -a ${LOG} + fi +} + +log_setup() { + log "setup" "$@" +} + +log_host() { + testname=$1 + shift + log "test:${testname}:host" "$@" +} + +log_guest() { + testname=$1 + shift + log "test:${testname}:guest" "$@" +} + +test_vm_server_host_client() { + local testname="${FUNCNAME[0]#test_}" + + vm_ssh -- "${VSOCK_TEST}" \ + --mode=server \ + --control-port="${TEST_GUEST_PORT}" \ + --peer-cid=2 \ + 2>&1 | log_guest "${testname}" & + + vm_wait_for_listener ${TEST_GUEST_PORT} + + ${VSOCK_TEST} \ + --mode=client \ + --control-host=127.0.0.1 \ + --peer-cid="${VSOCK_CID}" \ + --control-port="${TEST_HOST_PORT}" 2>&1 | log_host "${testname}" + + rc=$? +} + +test_vm_client_host_server() { + local testname="${FUNCNAME[0]#test_}" + + ${VSOCK_TEST} \ + --mode "server" \ + --control-port "${TEST_HOST_PORT_LISTENER}" \ + --peer-cid "${VSOCK_CID}" 2>&1 | log_host "${testname}" & + + host_wait_for_listener + + vm_ssh -- "${VSOCK_TEST}" \ + --mode=client \ + --control-host=10.0.2.2 \ + --peer-cid=2 \ + --control-port="${TEST_HOST_PORT_LISTENER}" 2>&1 | log_guest "${testname}" + + rc=$? +} + +test_vm_loopback() { + local testname="${FUNCNAME[0]#test_}" + local port=60000 # non-forwarded local port + + vm_ssh -- ${VSOCK_TEST} \ + --mode=server \ + --control-port="${port}" \ + --peer-cid="${VSOCK_CID}" & + + vm_wait_for_listener ${port} + + vm_ssh -- ${VSOCK_TEST} \ + --mode=client \ + --control-host="127.0.0.1" \ + --control-port="${port}" \ + --peer-cid="${VSOCK_CID}" + + rc=$? +} + +run_test() { + unset IFS + local host_oops_cnt_before=$(dmesg | grep -i 'Oops' | wc -l) + local host_warn_cnt_before=$(dmesg --level=warn | wc -l) + local vm_oops_cnt_before=$(vm_ssh -- dmesg | grep -i 'Oops' | wc -l) + local vm_warn_cnt_before=$(vm_ssh -- dmesg --level=warn | wc -l) + + name=$(echo "${1}" | awk '{ print $1 }') + eval test_"${name}" + + local host_oops_cnt_after=$(dmesg | grep -i 'Oops' | wc -l) + if [[ ${host_oops_cnt_after} -gt ${host_oops_cnt_before} ]]; then + echo "${name}: kernel oops detected on host" | log_host ${name} + rc=1 + fi + + local host_warn_cnt_after=$(dmesg --level=warn | wc -l) + if [[ ${host_warn_cnt_after} -gt ${host_warn_cnt_before} ]]; then + echo "${name}: kernel warning detected on host" | log_host ${name} + rc=1 + fi + + local vm_oops_cnt_after=$(vm_ssh -- dmesg | grep -i 'Oops' | wc -l) + if [[ ${vm_oops_cnt_after} -gt ${vm_oops_cnt_before} ]]; then + echo "${name}: kernel oops detected on vm" | log_host ${name} + rc=1 + fi + + local vm_warn_cnt_after=$(vm_ssh -- dmesg --level=warn | wc -l) + if [[ ${vm_warn_cnt_after} -gt ${vm_warn_cnt_before} ]]; then + echo "${name}: kernel warning detected on vm" | log_host ${name} + rc=1 + fi +} + +while getopts :hvs o +do + case $o in + v) VERBOSE=1;; + s) SKIP_BUILD=1;; + h|*) usage;; + esac +done +shift $((OPTIND-1)) + +trap cleanup EXIT + +> ${LOG} +if (( SKIP_BUILD != 1 )); then + build +fi +log_setup "Booting up VM" +vm_setup +vm_wait_for_ssh +log_setup "VM booted up" + +IFS=" +" +cnt=0 +for t in ${tests}; do + rc=0 + run_test "${t}" + if [[ ${rc} != 0 ]]; then + cnt=$(( cnt + 1 )) + fi +done + +if [[ ${cnt} = 0 ]]; then + echo OK +else + echo FAILED: ${cnt} +fi +echo "Log: ${LOG}" +exit ${cnt} --- base-commit: cc04ed502457412960d215b9cd55f0d966fda255 change-id: 20250325-vsock-vmtest-b3a21d2102c2 Best regards, -- Bobby Eshleman <bobbyeshleman(a)gmail.com>

3 days

2
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[PATCH][next] selftests/perf_events: Fix spelling mistake "sycnhronize" -> "synchronize"

by Colin Ian King

There is a spelling mistake in an error message. Fix it. Signed-off-by: Colin Ian King <colin.i.king(a)gmail.com> --- tools/testing/selftests/perf_events/watermark_signal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/perf_events/watermark_signal.c b/tools/testing/selftests/perf_events/watermark_signal.c index 49dc1e831174..e03fe1b9bba2 100644 --- a/tools/testing/selftests/perf_events/watermark_signal.c +++ b/tools/testing/selftests/perf_events/watermark_signal.c @@ -75,7 +75,7 @@ TEST(watermark_signal) if (waitpid(child, &child_status, WSTOPPED) != child || !(WIFSTOPPED(child_status) && WSTOPSIG(child_status) == SIGSTOP)) { fprintf(stderr, - "failed to sycnhronize with child errno=%d status=%x\n", + "failed to synchronize with child errno=%d status=%x\n", errno, child_status); goto cleanup; -- 2.49.0

3 days, 2 hours

1
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[PATCH] fix(script): improve safety and formatting for WRITES_STRICT restore

by Alexander Shatalin

From: Alexander Shatalin <sashatalin03(a)gmail.com> This patch improves the safety when restoring WRITES_STRICT by ensuring: - The variable is not empty (`-n`) - The target file is writable (`-w`) Also improves formatting by quoting variables and following shell best practices. Signed-off-by: Alexander Shatalin <sashatalin03(a)gmail.com>

3 days, 2 hours

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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

3 days, 9 hours

7
43
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[PATCH] selftests: pid_namespace: Fix pid_max build with missing mount header

by Niko Nikolov

Add #include <sys/mount.h> to pid_max.c to fix build errors caused by implicit declarations of mount() and umount2(), and undefined symbols MS_PRIVATE, MS_REC, and MNT_DETACH. Signed-off-by: Niko Nikolov <nikolay.niko.nikolov(a)gmail.com> --- tools/testing/selftests/pid_namespace/pid_max.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/pid_namespace/pid_max.c b/tools/testing/selftests/pid_namespace/pid_max.c index 51c414faabb0..972bedc475f1 100644 --- a/tools/testing/selftests/pid_namespace/pid_max.c +++ b/tools/testing/selftests/pid_namespace/pid_max.c @@ -11,6 +11,7 @@ #include <string.h> #include <syscall.h> #include <sys/wait.h> +#include <sys/mount.h> #include "../kselftest_harness.h" #include "../pidfd/pidfd.h" -- 2.49.0

3 days, 12 hours

1
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[PATCH bpf-next v3 0/2] bpf: Allow access to const void pointer arguments in tracing programs

by KaFai Wan

If we try to access argument which is pointer to const void, it's an UNKNOWN type, verifier will fail to load. Use is_void_or_int_ptr to check if type is void or int pointer. Add a selftest to check it. --- KaFai Wan (2): bpf: Allow access to const void pointer arguments in tracing programs selftests/bpf: Add test to access const void pointer argument in tracing program kernel/bpf/btf.c | 13 +++---------- net/bpf/test_run.c | 8 +++++++- .../selftests/bpf/progs/verifier_btf_ctx_access.c | 12 ++++++++++++ 3 files changed, 22 insertions(+), 11 deletions(-) Changelog: v2->v3: Addressed comments from jirka - remove duplicate checks for void pointer Details in here: https://lore.kernel.org/bpf/20250416161756.1079178-1-kafai.wan@hotmail.com/ v1->v2: Addressed comments from jirka - use btf_type_is_void to check if type is void - merge is_void_ptr and is_int_ptr to is_void_or_int_ptr - fix selftests Details in here: https://lore.kernel.org/all/20250412170626.3638516-1-kafai.wan@hotmail.com/ -- 2.43.0

3 days, 14 hours

3
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