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[PATCH 00/46] Allow inlining C helpers into Rust when using LTO

by Alice Ryhl

This patch series adds __rust_helper to every single rust helper. The patches do not depend on each other, so maintainers please go ahead and pick up any patches relevant to your subsystem! Or provide your Acked-by so that Miguel can pick them up. These changes were generated by adding __rust_helper and running ClangFormat. Unrelated formatting changes were removed manually. Why is __rust_helper needed? ============================ Currently, C helpers cannot be inlined into Rust even when using LTO because LLVM detects slightly different options on the codegen units. * LLVM doesn't want to inline functions compiled with `-fno-delete-null-pointer-checks` with code compiled without. The C CGUs all have this enabled and Rust CGUs don't. Inlining is okay since this is one of the hardening features that does not change the ABI, and we shouldn't have null pointer dereferences in these helpers. * LLVM doesn't want to inline functions with different list of builtins. C side has `-fno-builtin-wcslen`; `wcslen` is not a Rust builtin, so they should be compatible, but LLVM does not perform inlining due to attributes mismatch. * clang and Rust doesn't have the exact target string. Clang generates `+cmov,+cx8,+fxsr` but Rust doesn't enable them (in fact, Rust will complain if `-Ctarget-feature=+cmov,+cx8,+fxsr` is used). x86-64 always enable these features, so they are in fact the same target string, but LLVM doesn't understand this and so inlining is inhibited. This can be bypassed with `--ignore-tti-inline-compatible`, but this is a hidden option. (This analysis was written by Gary Guo.) How is this fixed? ================== To fix this we need to add __always_inline to all helpers when compiling with LTO. However, it should not be added when running bindgen as bindgen will ignore functions marked inline. To achieve this, we are using a #define called __rust_helper that is defined differently depending on whether bindgen is running or not. Note that __rust_helper is currently always #defined to nothing. Changing it to __always_inline will happen separately in another patch series. Signed-off-by: Alice Ryhl <aliceryhl(a)google.com> --- Alice Ryhl (46): rust: auxiliary: add __rust_helper to helpers rust: barrier: add __rust_helper to helpers rust: binder: add __rust_helper to helpers rust: bitmap: add __rust_helper to helpers rust: bitops: add __rust_helper to helpers rust: blk: add __rust_helper to helpers rust: bug: add __rust_helper to helpers rust: clk: add __rust_helper to helpers rust: completion: add __rust_helper to helpers rust: cpu: add __rust_helper to helpers rust: cpufreq: add __rust_helper to helpers rust: cpumask: add __rust_helper to helpers rust: cred: add __rust_helper to helpers rust: device: add __rust_helper to helpers rust: dma: add __rust_helper to helpers rust: drm: add __rust_helper to helpers rust: err: add __rust_helper to helpers rust: fs: add __rust_helper to helpers rust: io: add __rust_helper to helpers rust: irq: add __rust_helper to helpers rust: jump_label: add __rust_helper to helpers rust: kunit: add __rust_helper to helpers rust: maple_tree: add __rust_helper to helpers rust: mm: add __rust_helper to helpers rust: of: add __rust_helper to helpers rust: pci: add __rust_helper to helpers rust: pid_namespace: add __rust_helper to helpers rust: platform: add __rust_helper to helpers rust: poll: add __rust_helper to helpers rust: processor: add __rust_helper to helpers rust: property: add __rust_helper to helpers rust: rbtree: add __rust_helper to helpers rust: rcu: add __rust_helper to helpers rust: refcount: add __rust_helper to helpers rust: regulator: add __rust_helper to helpers rust: scatterlist: add __rust_helper to helpers rust: security: add __rust_helper to helpers rust: slab: add __rust_helper to helpers rust: sync: add __rust_helper to helpers rust: task: add __rust_helper to helpers rust: time: add __rust_helper to helpers rust: uaccess: add __rust_helper to helpers rust: usb: add __rust_helper to helpers rust: wait: add __rust_helper to helpers rust: workqueue: add __rust_helper to helpers rust: xarray: add __rust_helper to helpers rust/helpers/auxiliary.c | 6 +++-- rust/helpers/barrier.c | 6 ++--- rust/helpers/binder.c | 13 ++++----- rust/helpers/bitmap.c | 6 +++-- rust/helpers/bitops.c | 11 +++++--- rust/helpers/blk.c | 4 +-- rust/helpers/bug.c | 4 +-- rust/helpers/build_bug.c | 2 +- rust/helpers/clk.c | 24 +++++++++-------- rust/helpers/completion.c | 2 +- rust/helpers/cpu.c | 2 +- rust/helpers/cpufreq.c | 3 ++- rust/helpers/cpumask.c | 32 +++++++++++++--------- rust/helpers/cred.c | 4 +-- rust/helpers/device.c | 16 +++++------ rust/helpers/dma.c | 15 ++++++----- rust/helpers/drm.c | 7 ++--- rust/helpers/err.c | 6 ++--- rust/helpers/fs.c | 2 +- rust/helpers/io.c | 64 +++++++++++++++++++++++--------------------- rust/helpers/irq.c | 6 +++-- rust/helpers/jump_label.c | 2 +- rust/helpers/kunit.c | 2 +- rust/helpers/maple_tree.c | 3 ++- rust/helpers/mm.c | 20 +++++++------- rust/helpers/mutex.c | 13 ++++----- rust/helpers/of.c | 2 +- rust/helpers/page.c | 9 ++++--- rust/helpers/pci.c | 13 +++++---- rust/helpers/pid_namespace.c | 8 +++--- rust/helpers/platform.c | 2 +- rust/helpers/poll.c | 5 ++-- rust/helpers/processor.c | 2 +- rust/helpers/property.c | 2 +- rust/helpers/rbtree.c | 5 ++-- rust/helpers/rcu.c | 4 +-- rust/helpers/refcount.c | 10 +++---- rust/helpers/regulator.c | 24 ++++++++++------- rust/helpers/scatterlist.c | 12 +++++---- rust/helpers/security.c | 26 ++++++++++-------- rust/helpers/signal.c | 2 +- rust/helpers/slab.c | 14 +++++----- rust/helpers/spinlock.c | 13 ++++----- rust/helpers/sync.c | 4 +-- rust/helpers/task.c | 24 ++++++++--------- rust/helpers/time.c | 12 ++++----- rust/helpers/uaccess.c | 8 +++--- rust/helpers/usb.c | 3 ++- rust/helpers/vmalloc.c | 7 ++--- rust/helpers/wait.c | 2 +- rust/helpers/workqueue.c | 8 +++--- rust/helpers/xarray.c | 10 +++---- 52 files changed, 280 insertions(+), 226 deletions(-) --- base-commit: 54e3eae855629702c566bd2e130d9f40e7f35bde change-id: 20251202-define-rust-helper-f7b531813007 Best regards, -- Alice Ryhl <aliceryhl(a)google.com>

4 weeks

[PATCH net v2] selftests: net: fix "buffer overflow detected" for tap.c

by Alice C. Munduruca

When the selftest 'tap.c' is compiled with '-D_FORTIFY_SOURCE=3', the strcpy() in rtattr_add_strsz() is replaced with a checked version which causes the test to consistently fail when compiled with toolchains for which this option is enabled by default. TAP version 13 1..3 # Starting 3 tests from 1 test cases. # RUN tap.test_packet_valid_udp_gso ... *** buffer overflow detected ***: terminated # test_packet_valid_udp_gso: Test terminated by assertion # FAIL tap.test_packet_valid_udp_gso not ok 1 tap.test_packet_valid_udp_gso # RUN tap.test_packet_valid_udp_csum ... *** buffer overflow detected ***: terminated # test_packet_valid_udp_csum: Test terminated by assertion # FAIL tap.test_packet_valid_udp_csum not ok 2 tap.test_packet_valid_udp_csum # RUN tap.test_packet_crash_tap_invalid_eth_proto ... *** buffer overflow detected ***: terminated # test_packet_crash_tap_invalid_eth_proto: Test terminated by assertion # FAIL tap.test_packet_crash_tap_invalid_eth_proto not ok 3 tap.test_packet_crash_tap_invalid_eth_proto # FAILED: 0 / 3 tests passed. # Totals: pass:0 fail:3 xfail:0 xpass:0 skip:0 error:0 A buffer overflow is detected by the fortified glibc __strcpy_chk() since the __builtin_object_size() of `RTA_DATA(rta)` is incorrectly reported as 1, even though there is ample space in its bounding buffer `req`. Using the unchecked function memcpy() here instead allows us to match the way rtattr_add_str() is written while avoiding the spurious test failure. Fixes: 2e64fe4624d1 ("selftests: add few test cases for tap driver") Signed-off-by: Alice C. Munduruca <alice.munduruca(a)canonical.com> --- tools/testing/selftests/net/tap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/net/tap.c b/tools/testing/selftests/net/tap.c index 247c3b3ac1c9..dd961b629295 100644 --- a/tools/testing/selftests/net/tap.c +++ b/tools/testing/selftests/net/tap.c @@ -67,7 +67,7 @@ static struct rtattr *rtattr_add_strsz(struct nlmsghdr *nh, unsigned short type, { struct rtattr *rta = rtattr_add(nh, type, strlen(s) + 1); - strcpy(RTA_DATA(rta), s); + memcpy(RTA_DATA(rta), s, strlen(s) + 1); return rta; } -- 2.48.1

4 weeks, 1 day

[PATCH v3 0/3] KVM ARM64 pre_fault_memory

by Jack Thomson

From: Jack Thomson <jackabt(a)amazon.com> This patch series adds ARM64 support for the KVM_PRE_FAULT_MEMORY feature, which was previously only available on x86 [1]. This allows us to reduce the number of stage-2 faults during execution. This is of benefit in post-copy migration scenarios, particularly in memory intensive applications, where we are experiencing high latencies due to the stage-2 faults. Patch Overview: - The first patch adds support for the KVM_PRE_FAULT_MEMORY ioctl on arm64. - The second patch updates the pre_fault_memory_test to support arm64. - The last patch extends the pre_fault_memory_test to cover different vm memory backings. === Changes Since v2 [2] === - Update fault info synthesize value. Thanks Suzuki - Remove change to selftests for unaligned mmap allocations. Thanks Sean [1]: https://lore.kernel.org/kvm/20240710174031.312055-1-pbonzini@redhat.com [2]: https://lore.kernel.org/linux-arm-kernel/20251013151502.6679-1-jackabt.amaz… Jack Thomson (3): KVM: arm64: Add pre_fault_memory implementation KVM: selftests: Enable pre_fault_memory_test for arm64 KVM: selftests: Add option for different backing in pre-fault tests Documentation/virt/kvm/api.rst | 3 +- arch/arm64/kvm/Kconfig | 1 + arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/mmu.c | 73 +++++++++++- tools/testing/selftests/kvm/Makefile.kvm | 1 + .../selftests/kvm/pre_fault_memory_test.c | 110 ++++++++++++++---- 6 files changed, 159 insertions(+), 30 deletions(-) base-commit: 8a4821412cf2c1429fffa07c012dd150f2edf78c -- 2.43.0

4 weeks, 1 day

[PATCH] kselftest/anon_inode: replace null pointers with empty arrays

by Clint George

Make use of empty (NULL-terminated) array instead of NULL pointer to avoid compiler errors while maintaining the behavior of the function intact Signed-off-by: Clint George <clintbgeorge(a)gmail.com> --- [] Testing: The diff between before and after of running the kselftest test of the module shows no regression on system with x86 architecture Let me know if any more testing is needed to be done [] Error log: ~/Desktop/kernel-dev/linux-v1/tools/testing/selftests/filesystems$ make LLVM=1 W=1 CC devpts_pts CC file_stressor CC anon_inode_test anon_inode_test.c:45:37: warning: null passed to a callee that requires a non-null argument [-Wnonnull] 45 | ASSERT_LT(execveat(fd_context, "", NULL, NULL, AT_EMPTY_PATH), 0); | ^~~~ /usr/lib/llvm-18/lib/clang/18/include/__stddef_null.h:26:14: note: expanded from macro 'NULL' 26 | #define NULL ((void*)0) | ^~~~~~~~~~ /home/clint/Desktop/kernel-dev/linux-v1/tools/testing/selftests/../../../tools/testing/selftests/kselftest_harness.h:535:11: note: expanded from macro 'ASSERT_LT' 535 | __EXPECT(expected, #expected, seen, #seen, <, 1) | ^~~~~~~~ /home/clint/Desktop/kernel-dev/linux-v1/tools/testing/selftests/../../../tools/testing/selftests/kselftest_harness.h:758:33: note: expanded from macro '__EXPECT' 758 | __typeof__(_expected) __exp = (_expected); \ | ^~~~~~~~~ 1 warning generated. tools/testing/selftests/filesystems/anon_inode_test.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/filesystems/anon_inode_test.c b/tools/testing/selftests/filesystems/anon_inode_test.c index 94c6c81c2..2c4c50500 100644 --- a/tools/testing/selftests/filesystems/anon_inode_test.c +++ b/tools/testing/selftests/filesystems/anon_inode_test.c @@ -42,7 +42,10 @@ TEST(anon_inode_no_exec) fd_context = sys_fsopen("tmpfs", 0); ASSERT_GE(fd_context, 0); - ASSERT_LT(execveat(fd_context, "", NULL, NULL, AT_EMPTY_PATH), 0); + char *const empty_argv[] = {NULL}; + char *const empty_envp[] = {NULL}; + + ASSERT_LT(execveat(fd_context, "", empty_argv, empty_envp, AT_EMPTY_PATH), 0); ASSERT_EQ(errno, EACCES); EXPECT_EQ(close(fd_context), 0); -- 2.43.0

4 weeks, 1 day

[PATCH] kselftest/coredump: use __builtin_trap() instead of null pointer

by Clint George

Use __builtin_trap() to truly crash the program instead of dereferencing null pointer which may be optimized by the compiler preventing the crash from occurring Signed-off-by: Clint George <clintbgeorge(a)gmail.com> --- [] Testing: The diff between before and after of running the kselftest test of the module shows no regression on system with x86 architecture Let me know if any more testing is needed to be done [] Error log: ~/Desktop/kernel-dev/linux-v1/tools/testing/selftests/coredump$ make LLVM=1 W=1 CC stackdump_test coredump_test_helpers.c:59:6: warning: indirection of non-volatile null pointer will be deleted, not trap [-Wnull-dereference] 59 | i = *(int *)NULL; | ^~~~~~~~~~~~ coredump_test_helpers.c:59:6: note: consider using __builtin_trap() or qualifying pointer with 'volatile' 1 warning generated. CC coredump_socket_test coredump_test_helpers.c:59:6: warning: indirection of non-volatile null pointer will be deleted, not trap [-Wnull-dereference] 59 | i = *(int *)NULL; | ^~~~~~~~~~~~ coredump_test_helpers.c:59:6: note: consider using __builtin_trap() or qualifying pointer with 'volatile' 1 warning generated. CC coredump_socket_protocol_test coredump_test_helpers.c:59:6: warning: indirection of non-volatile null pointer will be deleted, not trap [-Wnull-dereference] 59 | i = *(int *)NULL; | ^~~~~~~~~~~~ coredump_test_helpers.c:59:6: note: consider using __builtin_trap() or qualifying pointer with 'volatile' 1 warning generated. tools/testing/selftests/coredump/coredump_test_helpers.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/coredump/coredump_test_helpers.c b/tools/testing/selftests/coredump/coredump_test_helpers.c index a6f6d5f2a..5c8adee63 100644 --- a/tools/testing/selftests/coredump/coredump_test_helpers.c +++ b/tools/testing/selftests/coredump/coredump_test_helpers.c @@ -56,7 +56,7 @@ void crashing_child(void) pthread_create(&thread, NULL, do_nothing, NULL); /* crash on purpose */ - i = *(int *)NULL; + __builtin_trap(); } int create_detached_tmpfs(void) -- 2.43.0

4 weeks, 1 day

[PATCH 0/3] selftests/futex: fix the issue of abnormal test results caused by thread timing

by Yuwen Chen

On the Android arm32 platform, when performing the futex_requeue test, it will most likely return a failure. The specific reason is detailed in a commit[1] previously submitted by Edward Liaw. However, this commit cannot perfectly solve the problem. This is because using a barrier does not guarantee that the child thread will wait on futex_wait. This series of patches attempts to solve this problem by checking whether the child thread is in a sleeping state. This is because when the child thread goes to sleep, it indicates that it is waiting for the futex lock. Link: https://lore.kernel.org/all/20240918231102.234253-1-edliaw@google.com/

4 weeks, 1 day

[PATCH v3] lkdtm: Add lockdep related crash tests

by Tzung-Bi Shih

Introduce various lockdep related crash tests. Signed-off-by: Tzung-Bi Shih <tzungbi(a)kernel.org> --- v3: - Add some entries in tools/testing/selftests/lkdtm/tests.txt. v2: https://lore.kernel.org/all/20251117033337.3730681-1-tzungbi@kernel.org/ - Fix "warning: suggest braces around empty body in an 'else' statement [-Wempty-body]" reported by 0day test robot. v1: https://lore.kernel.org/lkml/20251114062535.1827309-1-tzungbi@kernel.org/T/… drivers/misc/lkdtm/Makefile | 1 + drivers/misc/lkdtm/core.c | 1 + drivers/misc/lkdtm/lkdtm.h | 1 + drivers/misc/lkdtm/lockdep.c | 98 +++++++++++++++++++++++++ tools/testing/selftests/lkdtm/tests.txt | 8 ++ 5 files changed, 109 insertions(+) create mode 100644 drivers/misc/lkdtm/lockdep.c diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile index 03ebe33185f9..830b71c8e6a0 100644 --- a/drivers/misc/lkdtm/Makefile +++ b/drivers/misc/lkdtm/Makefile @@ -11,6 +11,7 @@ lkdtm-$(CONFIG_LKDTM) += usercopy.o lkdtm-$(CONFIG_LKDTM) += kstack_erase.o lkdtm-$(CONFIG_LKDTM) += cfi.o lkdtm-$(CONFIG_LKDTM) += fortify.o +lkdtm-$(CONFIG_LKDTM) += lockdep.o lkdtm-$(CONFIG_PPC_64S_HASH_MMU) += powerpc.o KASAN_SANITIZE_stackleak.o := n diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c index 5732fd59a227..43e91388940f 100644 --- a/drivers/misc/lkdtm/core.c +++ b/drivers/misc/lkdtm/core.c @@ -96,6 +96,7 @@ static const struct crashtype_category *crashtype_categories[] = { &stackleak_crashtypes, &cfi_crashtypes, &fortify_crashtypes, + &lockdep_crashtypes, #ifdef CONFIG_PPC_64S_HASH_MMU &powerpc_crashtypes, #endif diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h index 015e0484026b..d2d97e6f323e 100644 --- a/drivers/misc/lkdtm/lkdtm.h +++ b/drivers/misc/lkdtm/lkdtm.h @@ -84,6 +84,7 @@ extern struct crashtype_category usercopy_crashtypes; extern struct crashtype_category stackleak_crashtypes; extern struct crashtype_category cfi_crashtypes; extern struct crashtype_category fortify_crashtypes; +extern struct crashtype_category lockdep_crashtypes; extern struct crashtype_category powerpc_crashtypes; /* Each category's init/exit routines. */ diff --git a/drivers/misc/lkdtm/lockdep.c b/drivers/misc/lkdtm/lockdep.c new file mode 100644 index 000000000000..e029e9e60ce6 --- /dev/null +++ b/drivers/misc/lkdtm/lockdep.c @@ -0,0 +1,98 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2025 Google LLC + * + * Tests related to lockdep warnings. + */ +#include "lkdtm.h" +#include <linux/cleanup.h> +#include <linux/irqflags.h> +#include <linux/mutex.h> +#include <linux/spinlock.h> +#include <linux/srcu.h> + +static DEFINE_SPINLOCK(lock_A); +static DEFINE_SPINLOCK(lock_B); + +/* For "WARNING: possible circular locking dependency detected". */ +static void lkdtm_LOCKDEP_CIRCULAR_LOCK(void) +{ + scoped_guard(spinlock, &lock_A) + scoped_guard(spinlock, &lock_B) {} + scoped_guard(spinlock, &lock_B) + scoped_guard(spinlock, &lock_A) {} +} + +/* For "WARNING: possible recursive locking detected". */ +static void lkdtm_LOCKDEP_RECURSIVE_LOCK(void) +{ + guard(spinlock)(&lock_A); + guard(spinlock)(&lock_A); +} + +/* For "WARNING: inconsistent lock state". */ +static void lkdtm_LOCKDEP_INCONSISTENT_LOCK(void) +{ + lockdep_softirq_enter(); + scoped_guard(spinlock, &lock_A) {} + lockdep_softirq_exit(); + + scoped_guard(spinlock, &lock_A) {} +} + +/* For "WARNING: Nested lock was not taken". */ +static void lkdtm_LOCKDEP_NESTED_LOCK_NOT_HELD(void) +{ + spin_lock_nest_lock(&lock_B, &lock_A); +} + +/* For "WARNING: bad unlock balance detected!". */ +static void lkdtm_LOCKDEP_BAD_UNLOCK_BALANCE(void) +{ + spin_unlock(&lock_A); +} + +/* For "WARNING: held lock freed!". */ +static void lkdtm_LOCKDEP_HELD_LOCK_FREED(void) +{ + spin_lock(&lock_A); + spin_lock_init(&lock_A); +} + +/* For "WARNING: lock held when returning to user space!". */ +static void lkdtm_LOCKDEP_HELD_LOCK(void) +{ + spin_lock(&lock_A); +} + +/* For "WARNING: suspicious RCU usage". */ +static void lkdtm_LOCKDEP_SUSPICIOUS_RCU(void) +{ + struct srcu_struct srcu; + void __rcu *res = NULL; + int idx; + + init_srcu_struct(&srcu); + + idx = srcu_read_lock(&srcu); + rcu_dereference(res); + srcu_read_unlock(&srcu, idx); + + cleanup_srcu_struct(&srcu); +} + +static struct crashtype crashtypes[] = { + CRASHTYPE(LOCKDEP_CIRCULAR_LOCK), + CRASHTYPE(LOCKDEP_RECURSIVE_LOCK), + CRASHTYPE(LOCKDEP_INCONSISTENT_LOCK), + CRASHTYPE(LOCKDEP_NESTED_LOCK_NOT_HELD), + CRASHTYPE(LOCKDEP_BAD_UNLOCK_BALANCE), + CRASHTYPE(LOCKDEP_HELD_LOCK_FREED), + CRASHTYPE(LOCKDEP_HELD_LOCK), + CRASHTYPE(LOCKDEP_SUSPICIOUS_RCU), +}; + +struct crashtype_category lockdep_crashtypes = { + .crashtypes = crashtypes, + .len = ARRAY_SIZE(crashtypes), +}; diff --git a/tools/testing/selftests/lkdtm/tests.txt b/tools/testing/selftests/lkdtm/tests.txt index cff124c1eddd..7b32dece3d3a 100644 --- a/tools/testing/selftests/lkdtm/tests.txt +++ b/tools/testing/selftests/lkdtm/tests.txt @@ -83,3 +83,11 @@ FORTIFY_STR_MEMBER detected buffer overflow FORTIFY_MEM_OBJECT detected buffer overflow FORTIFY_MEM_MEMBER detected field-spanning write PPC_SLB_MULTIHIT Recovered +#LOCKDEP_CIRCULAR_LOCK Lockdep can only trigger once +#LOCKDEP_RECURSIVE_LOCK Hangs the system +#LOCKDEP_INCONSISTENT_LOCK Lockdep can only trigger once +#LOCKDEP_NESTED_LOCK_NOT_HELD Cause a deadlock in subsequent lockdep tests +#LOCKDEP_BAD_UNLOCK_BALANCE Lockdep can only trigger once +#LOCKDEP_HELD_LOCK_FREED Lockdep can only trigger once +#LOCKDEP_HELD_LOCK Cause a deadlock in subsequent lockdep tests +#LOCKDEP_SUSPICIOUS_RCU Lockdep can only trigger once -- 2.52.0.305.g3fc767764a-goog

4 weeks, 1 day

Re: sea_to_user sefltest failure

by Sebastian Ott

On Thu, 11 Dec 2025, Jiaqi Yan wrote: > CONFIGs seem alright to me. Do you boot kernel with cmdline options like "default_hugepagesz=1G hugepagesz=1G hugepages=64", or dynamically set up > huge pages via "echo 64 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages"? Neither of these. When I do the test is skipped: # echo 64 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages # ./arm64/sea_to_user Random seed: 0x6b8b4567 # Mapped 0x40000 pages: gva=0x80000000 to gpa=0xff80000000 # Before EINJect: data=0xbaadcafe # EINJ_GVA=0x81234bad, einj_gpa=0xff81234bad, einj_hva=0xffff41234bad, einj_hpa=0x80241234bad ok 1 # SKIP EINJ module probably not loaded?sh: line 1: /sys/kernel/debug/apei/einj/error_type: No such file or directory Bail out! Failed to write EINJ entry: No such file or directory (2) # 1 skipped test(s) detected. Consider enabling relevant config options to improve coverage. # Planned tests != run tests (0 != 1) # Totals: pass:0 fail:0 xfail:0 xpass:0 skip:1 error:0

4 weeks, 1 day

[PATCH net-next v7 0/9] Add support for providers with large rx buffer

by Pavel Begunkov

Note: it's net/ only bits and doesn't include changes, which shoulf be merged separately and are posted separately. The full branch for convenience is at [1], and the patch is here: https://lore.kernel.org/io-uring/7486ab32e99be1f614b3ef8d0e9bc77015b173f7.1… Many modern NICs support configurable receive buffer lengths, and zcrx and memory providers can use buffers larger than 4K/PAGE_SIZE on x86 to improve performance. When paired with hw-gro larger rx buffer sizes can drastically reduce the number of buffers traversing the stack and save a lot of processing time. It also allows to give to users larger contiguous chunks of data. The idea was first floated around by Saeed during netdev conf 2024 and was asked about by a few folks. Single stream benchmarks showed up to ~30% CPU util improvement. E.g. comparison for 4K vs 32K buffers using a 200Gbit NIC: packets=23987040 (MB=2745098), rps=199559 (MB/s=22837) CPU %usr %nice %sys %iowait %irq %soft %idle 0 1.53 0.00 27.78 2.72 1.31 66.45 0.22 packets=24078368 (MB=2755550), rps=200319 (MB/s=22924) CPU %usr %nice %sys %iowait %irq %soft %idle 0 0.69 0.00 8.26 31.65 1.83 57.00 0.57 This series adds net infrastructure for memory providers configuring the size and implements it for bnxt. It's an opt-in feature for drivers, they should advertise support for the parameter in the qops and must check if the hardware supports the given size. It's limited to memory providers as it drastically simplifies implementation. It doesn't affect the fast path zcrx uAPI, and the sizes is defined in zcrx terms, which allows it to be flexible and adjusted in the future, see Patch 8 for details. A liburing example can be found at [2] full branch: [1] https://github.com/isilence/linux.git zcrx/large-buffers-v7 Liburing example: [2] https://github.com/isilence/liburing.git zcrx/rx-buf-len v7: - Add xa_destroy - Rebase v6: - Update docs and add a selftest v5: https://lore.kernel.org/netdev/cover.1760440268.git.asml.silence@gmail.com/ - Remove all unnecessary bits like configuration via netlink, and multi-stage queue configuration. v4: https://lore.kernel.org/all/cover.1760364551.git.asml.silence@gmail.com/ - Update fbnic qops - Propagate max buf len for hns3 - Use configured buf size in __bnxt_alloc_rx_netmem - Minor stylistic changes v3: https://lore.kernel.org/all/cover.1755499375.git.asml.silence@gmail.com/ - Rebased, excluded zcrx specific patches - Set agg_size_fac to 1 on warning v2: https://lore.kernel.org/all/cover.1754657711.git.asml.silence@gmail.com/ - Add MAX_PAGE_ORDER check on pp init - Applied comments rewording - Adjust pp.max_len based on order - Patch up mlx5 queue callbacks after rebase - Minor ->queue_mgmt_ops refactoring - Rebased to account for both fill level and agg_size_fac - Pass providers buf length in struct pp_memory_provider_params and apply it in __netdev_queue_confi(). - Use ->supported_ring_params to validate drivers support of set qcfg parameters. Jakub Kicinski (1): eth: bnxt: adjust the fill level of agg queues with larger buffers Pavel Begunkov (8): net: page pool: xa init with destroy on pp init net: page_pool: sanitise allocation order net: memzero mp params when closing a queue net: let pp memory provider to specify rx buf len eth: bnxt: store rx buffer size per queue eth: bnxt: allow providers to set rx buf size io_uring/zcrx: document area chunking parameter selftests: iou-zcrx: test large chunk sizes Documentation/networking/iou-zcrx.rst | 20 +++ drivers/net/ethernet/broadcom/bnxt/bnxt.c | 118 ++++++++++++++---- drivers/net/ethernet/broadcom/bnxt/bnxt.h | 2 + drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c | 6 +- drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h | 2 +- include/net/netdev_queues.h | 9 ++ include/net/page_pool/types.h | 1 + net/core/netdev_rx_queue.c | 14 ++- net/core/page_pool.c | 4 + .../selftests/drivers/net/hw/iou-zcrx.c | 72 +++++++++-- .../selftests/drivers/net/hw/iou-zcrx.py | 37 ++++++ 11 files changed, 236 insertions(+), 49 deletions(-) -- 2.52.0

1 month

[PATCH v4 0/3] VMM can handle guest SEA via KVM_EXIT_ARM_SEA

by Jiaqi Yan

Problem ======= When host APEI is unable to claim a synchronous external abort (SEA) during guest abort, today KVM directly injects an asynchronous SError into the VCPU then resumes it. The injected SError usually results in unpleasant guest kernel panic. One of the major situation of guest SEA is when VCPU consumes recoverable uncorrected memory error (UER), which is not uncommon at all in modern datacenter servers with large amounts of physical memory. Although SError and guest panic is sufficient to stop the propagation of corrupted memory, there is room to recover from an UER in a more graceful manner. Proposed Solution ================= The idea is, we can replay the SEA to the faulting VCPU. If the memory error consumption or the fault that cause SEA is not from guest kernel, the blast radius can be limited to the poison-consuming guest process, while the VM can keep running. In addition, instead of doing under the hood without involving userspace, there are benefits to redirect the SEA to VMM: - VM customers care about the disruptions caused by memory errors, and VMM usually has the responsibility to start the process of notifying the customers of memory error events in their VMs. For example some cloud provider emits a critical log in their observability UI [1], and provides a playbook for customers on how to mitigate disruptions to their workloads. - VMM can protect future memory error consumption by unmapping the poisoned pages from stage-2 page table with KVM userfault [2], or by splitting the memslot that contains the poisoned pages. - VMM can keep track of SEA events in the VM. When VMM thinks the status on the host or the VM is bad enough, e.g. number of distinct SEAs exceeds a threshold, it can restart the VM on another healthy host. - Behavior parity with x86 architecture. When machine check exception (MCE) is caused by VCPU, kernel or KVM signals userspace SIGBUS to let VMM either recover from the MCE, or terminate itself with VM. The prior RFC proposes to implement SIGBUS on arm64 as well, but Marc preferred KVM exit over signal [3]. However, implementation aside, returning SEA to VMM is on par with returning MCE to VMM. Once SEA is redirected to VMM, among other actions, VMM is encouraged to inject external aborts into the faulting VCPU. New UAPIs ========= This patchset introduces following userspace-visible changes to empower VMM to control what happens for SEA on guest memory: - KVM_CAP_ARM_SEA_TO_USER. While taking SEA, if userspace has enabled this new capability at VM creation, and the SEA is not owned by kernel allocated memory, instead of injecting SError, return KVM_EXIT_ARM_SEA to userspace. - KVM_EXIT_ARM_SEA. This is the VM exit reason VMM gets. The details about the SEA is provided in arm_sea as much as possible, including sanitized ESR value at EL2, faulting guest virtual and physical addresses if available. * From v3 [4] - Rebased on commit 3a8660878839 ("Linux 6.18-rc1"). - In selftest, print a message if GVA or GPA expects to be valid. * From v2 [5]: - Rebased on "[PATCH] KVM: arm64: nv: Handle SEAs due to VNCR redirection" [6] and kvmarm/next commit 7b8346bd9fce6 ("KVM: arm64: Don't attempt vLPI mappings when vPE allocation is disabled") - Took the host_owns_sea implementation from Oliver [7, 8]. - Excluded the guest SEA injection patches. - Updated selftest. * From v1 [9]: - Rebased on commit 4d62121ce9b5 ("KVM: arm64: vgic-debug: Avoid dereferencing NULL ITE pointer"). - Sanitize ESR_EL2 before reporting it to userspace. - Do not do KVM_EXIT_ARM_SEA when SEA is caused by memory allocated to stage-2 translation table. [1] https://cloud.google.com/solutions/sap/docs/manage-host-errors [2] https://lore.kernel.org/kvm/20250109204929.1106563-1-jthoughton@google.com [3] https://lore.kernel.org/kvm/86pljbqqh0.wl-maz@kernel.org [4] https://lore.kernel.org/kvmarm/20250731205844.1346839-1-jiaqiyan@google.com [5] https://lore.kernel.org/kvm/20250604050902.3944054-1-jiaqiyan@google.com [6] https://lore.kernel.org/kvmarm/20250729182342.3281742-1-oliver.upton@linux.… [7] https://lore.kernel.org/kvm/aHFohmTb9qR_JG1E@linux.dev [8] https://lore.kernel.org/kvm/aHK-DPufhLy5Dtuk@linux.dev [9] https://lore.kernel.org/kvm/20250505161412.1926643-1-jiaqiyan@google.com Jiaqi Yan (3): KVM: arm64: VM exit to userspace to handle SEA KVM: selftests: Test for KVM_EXIT_ARM_SEA Documentation: kvm: new UAPI for handling SEA Documentation/virt/kvm/api.rst | 61 ++++ arch/arm64/include/asm/kvm_host.h | 2 + arch/arm64/kvm/arm.c | 5 + arch/arm64/kvm/mmu.c | 68 +++- include/uapi/linux/kvm.h | 10 + tools/arch/arm64/include/asm/esr.h | 2 + tools/testing/selftests/kvm/Makefile.kvm | 1 + .../testing/selftests/kvm/arm64/sea_to_user.c | 331 ++++++++++++++++++ tools/testing/selftests/kvm/lib/kvm_util.c | 1 + 9 files changed, 480 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/kvm/arm64/sea_to_user.c -- 2.51.0.760.g7b8bcc2412-goog

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