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 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 (9):
skbuff: Introduce SKB_EXT_TUN_VNET_HASH
virtio_net: Add functions for hashing
net: flow_dissector: Export flow_keys_dissector_symmetric
tap: Pad virtio header with zero
tun: Pad virtio header with zero
tun: Introduce virtio-net hash reporting feature
tun: Introduce virtio-net RSS
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 | 2 +-
drivers/net/tun.c | 255 ++++++++++++--
drivers/vhost/net.c | 16 +-
include/linux/if_tun.h | 5 +
include/linux/skbuff.h | 3 +
include/linux/virtio_net.h | 174 +++++++++
include/net/flow_dissector.h | 1 +
include/uapi/linux/if_tun.h | 71 ++++
net/core/flow_dissector.c | 3 +-
net/core/skbuff.c | 4 +
tools/testing/selftests/net/Makefile | 2 +-
tools/testing/selftests/net/tun.c | 666 ++++++++++++++++++++++++++++++++++-
14 files changed, 1170 insertions(+), 40 deletions(-)
---
base-commit: 752ebcbe87aceeb6334e846a466116197711a982
change-id: 20240403-rss-e737d89efa77
Best regards,
--
Akihiko Odaki <akihiko.odaki(a)daynix.com>
This patch allows progs to elide a null check on statically known map
lookup keys. In other words, if the verifier can statically prove that
the lookup will be in-bounds, allow the prog to drop the null check.
This is useful for two reasons:
1. Large numbers of nullness checks (especially when they cannot fail)
unnecessarily pushes prog towards BPF_COMPLEXITY_LIMIT_JMP_SEQ.
2. It forms a tighter contract between programmer and verifier.
For (1), bpftrace is starting to make heavier use of percpu scratch
maps. As a result, for user scripts with large number of unrolled loops,
we are starting to hit jump complexity verification errors. These
percpu lookups cannot fail anyways, as we only use static key values.
Eliding nullness probably results in less work for verifier as well.
For (2), percpu scratch maps are often used as a larger stack, as the
currrent stack is limited to 512 bytes. In these situations, it is
desirable for the programmer to express: "this lookup should never fail,
and if it does, it means I messed up the code". By omitting the null
check, the programmer can "ask" the verifier to double check the logic.
Changes in v3:
* Check if stack is (erroneously) growing upwards
* Mention in commit message why existing tests needed change
Changes in v2:
* Added a check for when R2 is not a ptr to stack
* Added a check for when stack is uninitialized (no stack slot yet)
* Updated existing tests to account for null elision
* Added test case for when R2 can be both const and non-const
Daniel Xu (2):
bpf: verifier: Support eliding map lookup nullness
bpf: selftests: verifier: Add nullness elision tests
kernel/bpf/verifier.c | 67 ++++++-
tools/testing/selftests/bpf/progs/iters.c | 14 +-
.../selftests/bpf/progs/map_kptr_fail.c | 2 +-
.../bpf/progs/verifier_array_access.c | 166 ++++++++++++++++++
.../selftests/bpf/progs/verifier_map_in_map.c | 2 +-
.../testing/selftests/bpf/verifier/map_kptr.c | 2 +-
6 files changed, 242 insertions(+), 11 deletions(-)
--
2.46.0
From: Joshua Hahn <joshua.hahn6(a)gmail.com>
v2 -> v3: Signed-off-by & renamed subject for clarity.
v1 -> v2: Edited commit messages for clarity.
Niced CPU usage is a metric reported in host-level /prot/stat, but is
not reported in cgroup-level statistics in cpu.stat. However, when a
host contains multiple tasks across different workloads, it becomes
difficult to gauge how much of the task is being spent on niced
processes based on /proc/stat alone, since host-level metrics do not
provide this cgroup-level granularity.
Exposing this metric will allow users to accurately probe the niced CPU
metric for each workload, and make more informed decisions when
directing higher priority tasks.
Joshua Hahn (2):
Tracking cgroup-level niced CPU time
Selftests for niced CPU statistics
include/linux/cgroup-defs.h | 1 +
kernel/cgroup/rstat.c | 16 ++++-
tools/testing/selftests/cgroup/test_cpu.c | 72 +++++++++++++++++++++++
3 files changed, 86 insertions(+), 3 deletions(-)
--
2.43.5
The PSCI v1.3 spec (https://developer.arm.com/documentation/den0022)
adds support for a SYSTEM_OFF2 function enabling a HIBERNATE_OFF state
which is analogous to ACPI S4. This will allow hosting environments to
determine that a guest is hibernated rather than just powered off, and
ensure that they preserve the virtual environment appropriately to
allow the guest to resume safely (or bump the hardware_signature in the
FACS to trigger a clean reboot instead).
This updates KVM to support advertising PSCI v1.3, and unconditionally
enables the SYSTEM_OFF2 support when PSCI v1.3 is enabled.
For the guest side, add a new SYS_OFF_MODE_POWER_OFF handler with higher
priority than the EFI one, but which *only* triggers when there's a
hibernation in progress. There are other ways to do this (see the commit
message for more details) but this seemed like the simplest.
Version 2 of the patch series splits out the psci.h definitions into a
separate commit (a dependency for both the guest and KVM side), and adds
definitions for the other new functions added in v1.3. It also moves the
pKVM psci-relay support to a separate commit; although in arch/arm64/kvm
that's actually about the *guest* side of SYSTEM_OFF2 (i.e. using it
from the host kernel, relayed through nVHE).
Version 3 dropped the KVM_CAP which allowed userspace to explicitly opt
in to the new feature like with SYSTEM_SUSPEND, and makes it depend only
on PSCI v1.3 being exposed to the guest.
Version 4 is no longer RFC, as the PSCI v1.3 spec is finally published.
Minor fixes from the last round of review, and an added KVM self test.
Version 5 drops some of the changes which didn't make it to the final
v1.3 spec, and cleans up a couple of places which still referred to it
as 'alpha' or 'beta'. It also temporarily drops the guest-side patch to
invoke SYSTEM_OFF2 for hibernation, pending confirmation that the final
PSCI v1.3 spec just has a typo where it changed to saying that 0x1
should be passed to mean HIBERNATE_OFF, even though it's advertised as
bit 0. That can be sent under separate cover, and perhaps should have
been anyway. The change in question doesn't matter for any of the KVM
patches, because we just treat SYSTEM_OFF2 like the existing
SYSTEM_RESET2, setting a flag to indicate that it was a SYSTEM_OFF2
call, but not actually caring about the argument; that's for userspace
to worry about.
David Woodhouse (5):
firmware/psci: Add definitions for PSCI v1.3 specification
KVM: arm64: Add PSCI v1.3 SYSTEM_OFF2 function for hibernation
KVM: arm64: Add support for PSCI v1.2 and v1.3
KVM: selftests: Add test for PSCI SYSTEM_OFF2
KVM: arm64: nvhe: Pass through PSCI v1.3 SYSTEM_OFF2 call
Documentation/virt/kvm/api.rst | 11 +++++
arch/arm64/include/uapi/asm/kvm.h | 6 +++
arch/arm64/kvm/hyp/nvhe/psci-relay.c | 2 +
arch/arm64/kvm/hypercalls.c | 2 +
arch/arm64/kvm/psci.c | 43 ++++++++++++++++-
include/kvm/arm_psci.h | 4 +-
include/uapi/linux/psci.h | 5 ++
tools/testing/selftests/kvm/aarch64/psci_test.c | 61 +++++++++++++++++++++++++
8 files changed, 132 insertions(+), 2 deletions(-)
The recent addition of support for testing with the x86 specific quirk
KVM_X86_QUIRK_SLOT_ZAP_ALL disabled in the generic memslot tests broke the
build of the KVM selftests for all other architectures:
In file included from include/kvm_util.h:8,
from include/memstress.h:13,
from memslot_modification_stress_test.c:21:
memslot_modification_stress_test.c: In function ‘main’:
memslot_modification_stress_test.c:176:38: error: ‘KVM_X86_QUIRK_SLOT_ZAP_ALL’ undeclared (first use in this function)
176 | KVM_X86_QUIRK_SLOT_ZAP_ALL);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
Add __x86_64__ guard defines to avoid building the relevant code on other
architectures.
Fixes: 61de4c34b51c ("KVM: selftests: Test memslot move in memslot_perf_test with quirk disabled")
Fixes: 218f6415004a ("KVM: selftests: Allow slot modification stress test with quirk disabled")
Reported-by: Aishwarya TCV <aishwarya.tcv(a)arm.com>
Signed-off-by: Mark Brown <broonie(a)kernel.org>
---
This is obviously disruptive for testing of KVM changes on non-x86
architectures.
---
tools/testing/selftests/kvm/memslot_modification_stress_test.c | 2 ++
tools/testing/selftests/kvm/memslot_perf_test.c | 6 ++++++
2 files changed, 8 insertions(+)
diff --git a/tools/testing/selftests/kvm/memslot_modification_stress_test.c b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
index e3343f0df9e1..c81a84990eab 100644
--- a/tools/testing/selftests/kvm/memslot_modification_stress_test.c
+++ b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
@@ -169,12 +169,14 @@ int main(int argc, char *argv[])
case 'i':
p.nr_iterations = atoi_positive("Number of iterations", optarg);
break;
+#ifdef __x86_64__
case 'q':
p.disable_slot_zap_quirk = true;
TEST_REQUIRE(kvm_check_cap(KVM_CAP_DISABLE_QUIRKS2) &
KVM_X86_QUIRK_SLOT_ZAP_ALL);
break;
+#endif
case 'h':
default:
help(argv[0]);
diff --git a/tools/testing/selftests/kvm/memslot_perf_test.c b/tools/testing/selftests/kvm/memslot_perf_test.c
index 893366982f77..989ffe0d047f 100644
--- a/tools/testing/selftests/kvm/memslot_perf_test.c
+++ b/tools/testing/selftests/kvm/memslot_perf_test.c
@@ -113,7 +113,9 @@ static_assert(ATOMIC_BOOL_LOCK_FREE == 2, "atomic bool is not lockless");
static sem_t vcpu_ready;
static bool map_unmap_verify;
+#ifdef __x86_64__
static bool disable_slot_zap_quirk;
+#endif
static bool verbose;
#define pr_info_v(...) \
@@ -579,8 +581,10 @@ static bool test_memslot_move_prepare(struct vm_data *data,
uint32_t guest_page_size = data->vm->page_size;
uint64_t movesrcgpa, movetestgpa;
+#ifdef __x86_64__
if (disable_slot_zap_quirk)
vm_enable_cap(data->vm, KVM_CAP_DISABLE_QUIRKS2, KVM_X86_QUIRK_SLOT_ZAP_ALL);
+#endif
movesrcgpa = vm_slot2gpa(data, data->nslots - 1);
@@ -971,11 +975,13 @@ static bool parse_args(int argc, char *argv[],
case 'd':
map_unmap_verify = true;
break;
+#ifdef __x86_64__
case 'q':
disable_slot_zap_quirk = true;
TEST_REQUIRE(kvm_check_cap(KVM_CAP_DISABLE_QUIRKS2) &
KVM_X86_QUIRK_SLOT_ZAP_ALL);
break;
+#endif
case 's':
targs->nslots = atoi_paranoid(optarg);
if (targs->nslots <= 1 && targs->nslots != -1) {
---
base-commit: 9852d85ec9d492ebef56dc5f229416c925758edc
change-id: 20240930-kvm-build-breakage-a542f46d78f9
Best regards,
--
Mark Brown <broonie(a)kernel.org>
The HID test cases actually run tests using the run-hid-tools-tests.sh
script. However, if installed with "make install", the run-hid-tools-tests.sh
script will not be copied over, resulting in the following error message.
make -C tools/testing/selftests/ TARGETS=hid install \
INSTALL_PATH=$KSFT_INSTALL_PATH
cd $KSFT_INSTALL_PATH
./run_kselftest.sh -c hid
selftests: hid: hid-core.sh
bash: ./run-hid-tools-tests.sh: No such file or directory
So add the run-hid-tools-tests.sh script to the TEST_FILES in the Makefile.
Signed-off-by: Yun Lu <luyun(a)kylinos.cn>
---
tools/testing/selftests/hid/Makefile | 2 ++
1 file changed, 2 insertions(+)
diff --git a/tools/testing/selftests/hid/Makefile b/tools/testing/selftests/hid/Makefile
index 72be55ac4bdf..38ae31bb07b5 100644
--- a/tools/testing/selftests/hid/Makefile
+++ b/tools/testing/selftests/hid/Makefile
@@ -17,6 +17,8 @@ TEST_PROGS += hid-tablet.sh
TEST_PROGS += hid-usb_crash.sh
TEST_PROGS += hid-wacom.sh
+TEST_FILES := run-hid-tools-tests.sh
+
CXX ?= $(CROSS_COMPILE)g++
HOSTPKG_CONFIG := pkg-config
--
2.27.0