virtio-net have two usage of hashes: one is RSS and another is hash
reporting. Conventionally the hash calculation was done by the VMM.
However, computing the hash after the queue was chosen defeats the
purpose of RSS.
Another approach is to use eBPF steering program. This approach has
another downside: it cannot report the calculated hash due to the
restrictive nature of eBPF.
Introduce the code to compute hashes to the kernel in order to overcome
thse challenges.
An alternative solution is to extend the eBPF steering program so that it
will be able to report to the userspace, but it is based on context
rewrites, which is in feature freeze. We can adopt kfuncs, but they will
not be UAPIs. We opt to ioctl to align with other relevant UAPIs (KVM
and vhost_net).
The patches for QEMU to use this new feature was submitted as RFC and
is available at:
https://patchew.org/QEMU/20240915-hash-v3-0-79cb08d28647@daynix.com/
This work was presented at LPC 2024:
https://lpc.events/event/18/contributions/1963/
V1 -> V2:
Changed to introduce a new BPF program type.
Signed-off-by: Akihiko Odaki <akihiko.odaki(a)daynix.com>
---
Changes in v9:
- Added a missing return statement in patch
"tun: Introduce virtio-net hash feature".
- Link to v8: https://lore.kernel.org/r/20250306-rss-v8-0-7ab4f56ff423@daynix.com
Changes in v8:
- Disabled IPv6 to eliminate noises in tests.
- Added a branch in tap to avoid unnecessary dissection when hash
reporting is disabled.
- Removed unnecessary rtnl_lock().
- Extracted code to handle new ioctls into separate functions to avoid
adding extra NULL checks to the code handling other ioctls.
- Introduced variable named "fd" to __tun_chr_ioctl().
- s/-/=/g in a patch message to avoid confusing Git.
- Link to v7: https://lore.kernel.org/r/20250228-rss-v7-0-844205cbbdd6@daynix.com
Changes in v7:
- Ensured to set hash_report to VIRTIO_NET_HASH_REPORT_NONE for
VHOST_NET_F_VIRTIO_NET_HDR.
- s/4/sizeof(u32)/ in patch "virtio_net: Add functions for hashing".
- Added tap_skb_cb type.
- Rebased.
- Link to v6: https://lore.kernel.org/r/20250109-rss-v6-0-b1c90ad708f6@daynix.com
Changes in v6:
- Extracted changes to fill vnet header holes into another series.
- Squashed patches "skbuff: Introduce SKB_EXT_TUN_VNET_HASH", "tun:
Introduce virtio-net hash reporting feature", and "tun: Introduce
virtio-net RSS" into patch "tun: Introduce virtio-net hash feature".
- Dropped the RFC tag.
- Link to v5: https://lore.kernel.org/r/20241008-rss-v5-0-f3cf68df005d@daynix.com
Changes in v5:
- Fixed a compilation error with CONFIG_TUN_VNET_CROSS_LE.
- Optimized the calculation of the hash value according to:
https://git.dpdk.org/dpdk/commit/?id=3fb1ea032bd6ff8317af5dac9af901f1f324ca…
- Added patch "tun: Unify vnet implementation".
- Dropped patch "tap: Pad virtio header with zero".
- Added patch "selftest: tun: Test vnet ioctls without device".
- Reworked selftests to skip for older kernels.
- Documented the case when the underlying device is deleted and packets
have queue_mapping set by TC.
- Reordered test harness arguments.
- Added code to handle fragmented packets.
- Link to v4: https://lore.kernel.org/r/20240924-rss-v4-0-84e932ec0e6c@daynix.com
Changes in v4:
- Moved tun_vnet_hash_ext to if_tun.h.
- Renamed virtio_net_toeplitz() to virtio_net_toeplitz_calc().
- Replaced htons() with cpu_to_be16().
- Changed virtio_net_hash_rss() to return void.
- Reordered variable declarations in virtio_net_hash_rss().
- Removed virtio_net_hdr_v1_hash_from_skb().
- Updated messages of "tap: Pad virtio header with zero" and
"tun: Pad virtio header with zero".
- Fixed vnet_hash allocation size.
- Ensured to free vnet_hash when destructing tun_struct.
- Link to v3: https://lore.kernel.org/r/20240915-rss-v3-0-c630015db082@daynix.com
Changes in v3:
- Reverted back to add ioctl.
- Split patch "tun: Introduce virtio-net hashing feature" into
"tun: Introduce virtio-net hash reporting feature" and
"tun: Introduce virtio-net RSS".
- Changed to reuse hash values computed for automq instead of performing
RSS hashing when hash reporting is requested but RSS is not.
- Extracted relevant data from struct tun_struct to keep it minimal.
- Added kernel-doc.
- Changed to allow calling TUNGETVNETHASHCAP before TUNSETIFF.
- Initialized num_buffers with 1.
- Added a test case for unclassified packets.
- Fixed error handling in tests.
- Changed tests to verify that the queue index will not overflow.
- Rebased.
- Link to v2: https://lore.kernel.org/r/20231015141644.260646-1-akihiko.odaki@daynix.com
---
Akihiko Odaki (6):
virtio_net: Add functions for hashing
net: flow_dissector: Export flow_keys_dissector_symmetric
tun: Introduce virtio-net hash feature
selftest: tun: Test vnet ioctls without device
selftest: tun: Add tests for virtio-net hashing
vhost/net: Support VIRTIO_NET_F_HASH_REPORT
Documentation/networking/tuntap.rst | 7 +
drivers/net/Kconfig | 1 +
drivers/net/tap.c | 68 +++-
drivers/net/tun.c | 98 +++++-
drivers/net/tun_vnet.h | 159 ++++++++-
drivers/vhost/net.c | 49 +--
include/linux/if_tap.h | 2 +
include/linux/skbuff.h | 3 +
include/linux/virtio_net.h | 188 ++++++++++
include/net/flow_dissector.h | 1 +
include/uapi/linux/if_tun.h | 75 ++++
net/core/flow_dissector.c | 3 +-
net/core/skbuff.c | 4 +
tools/testing/selftests/net/Makefile | 2 +-
tools/testing/selftests/net/tun.c | 656 ++++++++++++++++++++++++++++++++++-
15 files changed, 1255 insertions(+), 61 deletions(-)
---
base-commit: dd83757f6e686a2188997cb58b5975f744bb7786
change-id: 20240403-rss-e737d89efa77
prerequisite-change-id: 20241230-tun-66e10a49b0c7:v6
prerequisite-patch-id: 871dc5f146fb6b0e3ec8612971a8e8190472c0fb
prerequisite-patch-id: 2797ed249d32590321f088373d4055ff3f430a0e
prerequisite-patch-id: ea3370c72d4904e2f0536ec76ba5d26784c0cede
prerequisite-patch-id: 837e4cf5d6b451424f9b1639455e83a260c4440d
prerequisite-patch-id: ea701076f57819e844f5a35efe5cbc5712d3080d
prerequisite-patch-id: 701646fb43ad04cc64dd2bf13c150ccbe6f828ce
prerequisite-patch-id: 53176dae0c003f5b6c114d43f936cf7140d31bb5
prerequisite-change-id: 20250116-buffers-96e14bf023fc:v2
prerequisite-patch-id: 25fd4f99d4236a05a5ef16ab79f3e85ee57e21cc
Best regards,
--
Akihiko Odaki <akihiko.odaki(a)daynix.com>
Hello there,
Static analyser cppcheck says:
> linux-6.14/tools/testing/selftests/mm/pagemap_ioctl.c:1061:11: style: int result is assigned to long long variable. If the variable is long long to avoid loss of information, then you have loss of information. [truncLongCastAssignment]
> linux-6.14/tools/testing/selftests/mm/pagemap_ioctl.c:1510:11: style: int result is assigned to long long variable. If the variable is long long to avoid loss of information, then you have loss of information. [truncLongCastAssignment]
> linux-6.14/tools/testing/selftests/mm/pagemap_ioctl.c:1523:11: style: int result is assigned to long long variable. If the variable is long long to avoid loss of information, then you have loss of information. [truncLongCastAssignment]
> linux-6.14/tools/testing/selftests/mm/pagemap_ioctl.c:247:11: style: int result is assigned to long long variable. If the variable is long long to avoid loss of information, then you have loss of information. [truncLongCastAssignment]
> linux-6.14/tools/testing/selftests/mm/pagemap_ioctl.c:435:11: style: int result is assigned to long long variable. If the variable is long long to avoid loss of information, then you have loss of information. [truncLongCastAssignment]
> linux-6.14/tools/testing/selftests/mm/pagemap_ioctl.c:490:11: style: int result is assigned to long long variable. If the variable is long long to avoid loss of information, then you have loss of information. [truncLongCastAssignment]
The source code of the first one is
mem_size = 10 * page_size;
Maybe better code:
mem_size = 10ULL * page_size;
Regards
David Binderman
My randconfig builds sometimes (around one in every 700 configs) run
into this warning on x86:
Symbol __pfx_snnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7n too long for kallsyms (517 >= 512).
Please increase KSYM_NAME_LEN both in kernel and kallsyms.c
The check that gets triggered was added in commit c104c16073b
("Kunit to check the longest symbol length"), see
https://lore.kernel.org/all/20241117195923.222145-1-sergio.collado@gmail.co…
and the overlong identifier seems to be the result of objtool adding
the six-byte "__pfx_" string to a symbol in elf_create_prefix_symbol()
when CONFIG_FUNCTION_PADDING_CFI is set.
I think the suggestion to "Please increase KSYM_NAME_LEN both in
kernel and kallsyms.c" is misleading here and should probably be
changed. I don't know if this something that objtool should work
around, or something that needs to be adapted in the test.
Arnd
Fix a misspelling of "slow".
Signed-off-by: Geert Uytterhoeven <geert(a)linux-m68k.org>
---
include/kunit/test.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/kunit/test.h b/include/kunit/test.h
index 58dbab60f8530588..9b773406e01f3c43 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -67,7 +67,7 @@ enum kunit_status {
/*
* Speed Attribute is stored as an enum and separated into categories of
- * speed: very_slowm, slow, and normal. These speeds are relative to
+ * speed: very_slow, slow, and normal. These speeds are relative to
* other KUnit tests.
*
* Note: unset speed attribute acts as default of KUNIT_SPEED_NORMAL.
--
2.43.0
Hi Linus,
Please pull the following kselftest next update for Linux 6.15-rc1.
Fixes bugs and cleans up code in tracing, ftrace, and user_events tests.
Adds missing executables to ftrace gitignore.
diff is attached.
thanks,
-- Shuah
----------------------------------------------------------------
The following changes since commit a64dcfb451e254085a7daee5fe51bf22959d52d3:
Linux 6.14-rc2 (2025-02-09 12:45:03 -0800)
are available in the Git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest tags/linux_kselftest-next-6.15-rc1
for you to fetch changes up to 82ef781f24ac26f4aa71f02d7624c439ab8389a7:
selftests/ftrace: add 'poll' binary to gitignore (2025-03-04 08:51:17 -0700)
----------------------------------------------------------------
linux_kselftest-next-6.15-rc1
Fixes bugs and cleans up code in tracing, ftrace, and user_events tests.
Adds missing executables to ftrace gitignore.
----------------------------------------------------------------
Bharadwaj Raju (1):
selftests/ftrace: add 'poll' binary to gitignore
Heiko Carstens (1):
selftests/ftrace: Use readelf to find entry point in uprobe test
Steven Rostedt (3):
selftests/tracing: Test only toplevel README file not the instances
selftests/ftrace: Clean up triggers after setting them
selftests/tracing: Allow some more tests to run in instances
Yiqian Xun (1):
selftests/user_events: Fix failures caused by test code
tools/testing/selftests/ftrace/.gitignore | 1 +
.../selftests/ftrace/test.d/dynevent/add_remove_uprobe.tc | 10 +++++++---
tools/testing/selftests/ftrace/test.d/functions | 8 +++++++-
.../test.d/trigger/inter-event/trigger-action-hist-xfail.tc | 1 +
.../test.d/trigger/inter-event/trigger-onchange-action-hist.tc | 3 +++
.../test.d/trigger/inter-event/trigger-snapshot-action-hist.tc | 3 +++
.../ftrace/test.d/trigger/trigger-hist-expressions.tc | 1 +
tools/testing/selftests/user_events/dyn_test.c | 2 ++
8 files changed, 25 insertions(+), 4 deletions(-)
----------------------------------------------------------------
Hi Linus,
Please pull the following kunit next update for Linux 6.15-rc1.
kunit tool:
- Changes to kunit tool to use qboot on QEMU x86_64, and build GDB scripts.
- Fixes kunit tool bug in parsing test plan.
- Adds test to kunit tool to check parsing late test plan.
kunit:
- Clarifies kunit_skip() argument name.
- Adds Kunit check for the longest symbol length.
- Changes qemu_configs for sparc to use Zilog console.
Conflicts in lib/Makefile
between commit:
b341f6fd45ab ("blackhole_dev: convert self-test to KUnit")
from the net-next tree and commit:
c104c16073b7 ("Kunit to check the longest symbol length")
The commit c104c16073b7 conflicts with the mainline now with
62f3802332ed ("vdso: add generic time data storage") from kspp
is now in the mainline.
Stephen has the fixes for these two conflicts in next.
(Thank you Stephen)
diff is attached.
thanks,
-- Shuah
----------------------------------------------------------------
The following changes since commit a64dcfb451e254085a7daee5fe51bf22959d52d3:
Linux 6.14-rc2 (2025-02-09 12:45:03 -0800)
are available in the Git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest tags/linux_kselftest-kunit-6.15-rc1
for you to fetch changes up to 2e0cf2b32f72b20b0db5cc665cd8465d0f257278:
kunit: tool: add test to check parsing late test plan (2025-03-15 18:13:43 -0600)
----------------------------------------------------------------
linux_kselftest-kunit-6.15-rc1
kunit tool:
- Changes to kunit tool to use qboot on QEMU x86_64, and build GDB scripts.
- Fixes kunit tool bug in parsing test plan.
- Adds test to kunit tool to check parsing late test plan.
kunit:
- Clarifies kunit_skip() argument name.
- Adds Kunit check for the longest symbol length.
- Changes qemu_configs for sparc to use Zilog console.
----------------------------------------------------------------
Brendan Jackman (2):
kunit: tool: Use qboot on QEMU x86_64
kunit: tool: Build GDB scripts
Kevin Brodsky (1):
kunit: Clarify kunit_skip() argument name
Rae Moar (2):
kunit: tool: Fix bug in parsing test plan
kunit: tool: add test to check parsing late test plan
Sergio González Collado (1):
Kunit to check the longest symbol length
Thomas Weißschuh (1):
kunit: qemu_configs: sparc: use Zilog console
arch/x86/tools/insn_decoder_test.c | 3 +-
include/kunit/test.h | 20 ++++----
lib/Kconfig.debug | 9 ++++
lib/Makefile | 2 +
lib/longest_symbol_kunit.c | 82 ++++++++++++++++++++++++++++++
tools/testing/kunit/kunit_kernel.py | 4 +-
tools/testing/kunit/kunit_parser.py | 9 ++--
tools/testing/kunit/kunit_tool_test.py | 11 ++++
tools/testing/kunit/qemu_configs/sparc.py | 5 +-
tools/testing/kunit/qemu_configs/x86_64.py | 4 +-
10 files changed, 128 insertions(+), 21 deletions(-)
create mode 100644 lib/longest_symbol_kunit.c
----------------------------------------------------------------
This started with a patch that enabled `clippy::ptr_as_ptr`. Benno
Lossin suggested I also look into `clippy::ptr_cast_constness` and I
discovered `clippy::as_ptr_cast_mut`. This series now enables all 3
lints. It also enables `clippy::as_underscore` which ensures other
pointer casts weren't missed. The first commit reduces the need for
pointer casts and is shared with another series[1].
As a later addition, `clippy::cast_lossless` and `clippy::ref_as_ptr`
are also enabled.
Link: https://lore.kernel.org/all/20250307-no-offset-v1-0-0c728f63b69c@gmail.com/ [1]
Signed-off-by: Tamir Duberstein <tamird(a)gmail.com>
---
Changes in v7:
- Add patch to enable `clippy::ref_as_ptr`.
- Link to v6: https://lore.kernel.org/r/20250324-ptr-as-ptr-v6-0-49d1b7fd4290@gmail.com
Changes in v6:
- Drop strict provenance patch.
- Fix URLs in doc comments.
- Add patch to enable `clippy::cast_lossless`.
- Rebase on rust-next.
- Link to v5: https://lore.kernel.org/r/20250317-ptr-as-ptr-v5-0-5b5f21fa230a@gmail.com
Changes in v5:
- Use `pointer::addr` in OF. (Boqun Feng)
- Add documentation on stubs. (Benno Lossin)
- Mark stubs `#[inline]`.
- Pick up Alice's RB on a shared commit from
https://lore.kernel.org/all/Z9f-3Aj3_FWBZRrm@google.com/.
- Link to v4: https://lore.kernel.org/r/20250315-ptr-as-ptr-v4-0-b2d72c14dc26@gmail.com
Changes in v4:
- Add missing SoB. (Benno Lossin)
- Use `without_provenance_mut` in alloc. (Boqun Feng)
- Limit strict provenance lints to the `kernel` crate to avoid complex
logic in the build system. This can be revisited on MSRV >= 1.84.0.
- Rebase on rust-next.
- Link to v3: https://lore.kernel.org/r/20250314-ptr-as-ptr-v3-0-e7ba61048f4a@gmail.com
Changes in v3:
- Fixed clippy warning in rust/kernel/firmware.rs. (kernel test robot)
Link: https://lore.kernel.org/all/202503120332.YTCpFEvv-lkp@intel.com/
- s/as u64/as bindings::phys_addr_t/g. (Benno Lossin)
- Use strict provenance APIs and enable lints. (Benno Lossin)
- Link to v2: https://lore.kernel.org/r/20250309-ptr-as-ptr-v2-0-25d60ad922b7@gmail.com
Changes in v2:
- Fixed typo in first commit message.
- Added additional patches, converted to series.
- Link to v1: https://lore.kernel.org/r/20250307-ptr-as-ptr-v1-1-582d06514c98@gmail.com
---
Tamir Duberstein (7):
rust: retain pointer mut-ness in `container_of!`
rust: enable `clippy::ptr_as_ptr` lint
rust: enable `clippy::ptr_cast_constness` lint
rust: enable `clippy::as_ptr_cast_mut` lint
rust: enable `clippy::as_underscore` lint
rust: enable `clippy::cast_lossless` lint
rust: enable `clippy::ref_as_ptr` lint
Makefile | 6 ++++++
drivers/gpu/drm/drm_panic_qr.rs | 10 +++++-----
rust/bindings/lib.rs | 3 +++
rust/kernel/alloc/allocator_test.rs | 2 +-
rust/kernel/alloc/kvec.rs | 4 ++--
rust/kernel/block/mq/operations.rs | 2 +-
rust/kernel/block/mq/request.rs | 7 ++++---
rust/kernel/device.rs | 5 +++--
rust/kernel/device_id.rs | 5 +++--
rust/kernel/devres.rs | 19 ++++++++++---------
rust/kernel/dma.rs | 6 +++---
rust/kernel/error.rs | 2 +-
rust/kernel/firmware.rs | 3 ++-
rust/kernel/fs/file.rs | 3 ++-
rust/kernel/io.rs | 18 +++++++++---------
rust/kernel/kunit.rs | 15 +++++++--------
rust/kernel/lib.rs | 5 ++---
rust/kernel/list/impl_list_item_mod.rs | 2 +-
rust/kernel/miscdevice.rs | 2 +-
rust/kernel/net/phy.rs | 4 ++--
rust/kernel/of.rs | 6 +++---
rust/kernel/pci.rs | 13 ++++++++-----
rust/kernel/platform.rs | 6 ++++--
rust/kernel/print.rs | 11 +++++------
rust/kernel/rbtree.rs | 23 ++++++++++-------------
rust/kernel/seq_file.rs | 3 ++-
rust/kernel/str.rs | 14 +++++++-------
rust/kernel/sync/poll.rs | 2 +-
rust/kernel/uaccess.rs | 5 +++--
rust/kernel/workqueue.rs | 12 ++++++------
rust/uapi/lib.rs | 3 +++
31 files changed, 120 insertions(+), 101 deletions(-)
---
base-commit: 28bb48c4cb34f65a9aa602142e76e1426da31293
change-id: 20250307-ptr-as-ptr-21b1867fc4d4
Best regards,
--
Tamir Duberstein <tamird(a)gmail.com>