April 2025 - Linux-kselftest-mirror

[PATCH v7 0/6] mm/memfd: introduce MFD_NOEXEC_SEAL and MFD_EXEC

by jeffxu＠chromium.org

From: Jeff Xu <jeffxu(a)google.com> Since Linux introduced the memfd feature, memfd have always had their execute bit set, and the memfd_create() syscall doesn't allow setting it differently. However, in a secure by default system, such as ChromeOS, (where all executables should come from the rootfs, which is protected by Verified boot), this executable nature of memfd opens a door for NoExec bypass and enables “confused deputy attack”. E.g, in VRP bug [1]: cros_vm process created a memfd to share the content with an external process, however the memfd is overwritten and used for executing arbitrary code and root escalation. [2] lists more VRP in this kind. On the other hand, executable memfd has its legit use, runc uses memfd’s seal and executable feature to copy the contents of the binary then execute them, for such system, we need a solution to differentiate runc's use of executable memfds and an attacker's [3]. To address those above, this set of patches add following: 1> Let memfd_create() set X bit at creation time. 2> Let memfd to be sealed for modifying X bit. 3> A new pid namespace sysctl: vm.memfd_noexec to control the behavior of X bit.For example, if a container has vm.memfd_noexec=2, then memfd_create() without MFD_NOEXEC_SEAL will be rejected. 4> A new security hook in memfd_create(). This make it possible to a new LSM, which rejects or allows executable memfd based on its security policy. Change history: v7: - patch 2/6: remove #ifdef and MAX_PATH (memfd_test.c). - patch 3/6: check capability (CAP_SYS_ADMIN) from userns instead of global ns (pid_sysctl.h). Add a tab (pid_namespace.h). - patch 5/6: remove #ifdef (memfd_test.c) - patch 6/6: remove unneeded security_move_mount(security.c). v6:https://lore.kernel.org/lkml/20221206150233.1963717-1-jeffxu@google.com/ - Address comment and move "#ifdef CONFIG_" from .c file to pid_sysctl.h v5:https://lore.kernel.org/lkml/20221206152358.1966099-1-jeffxu@google.com/ - Pass vm.memfd_noexec from current ns to child ns. - Fix build issue detected by kernel test robot. - Add missing security.c v3:https://lore.kernel.org/lkml/20221202013404.163143-1-jeffxu@google.com/ - Address API design comments in v2. - Let memfd_create() to set X bit at creation time. - A new pid namespace sysctl: vm.memfd_noexec to control behavior of X bit. - A new security hook in memfd_create(). v2:https://lore.kernel.org/lkml/20220805222126.142525-1-jeffxu@google.com/ - address comments in V1. - add sysctl (vm.mfd_noexec) to set the default file permissions of memfd_create to be non-executable. v1:https://lwn.net/Articles/890096/ [1] https://crbug.com/1305411 [2] https://bugs.chromium.org/p/chromium/issues/list?q=type%3Dbug-security%20me… [3] https://lwn.net/Articles/781013/ Daniel Verkamp (2): mm/memfd: add F_SEAL_EXEC selftests/memfd: add tests for F_SEAL_EXEC Jeff Xu (4): mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC mm/memfd: Add write seals when apply SEAL_EXEC to executable memfd selftests/memfd: add tests for MFD_NOEXEC_SEAL MFD_EXEC mm/memfd: security hook for memfd_create include/linux/lsm_hook_defs.h | 1 + include/linux/lsm_hooks.h | 4 + include/linux/pid_namespace.h | 19 ++ include/linux/security.h | 6 + include/uapi/linux/fcntl.h | 1 + include/uapi/linux/memfd.h | 4 + kernel/pid_namespace.c | 5 + kernel/pid_sysctl.h | 59 ++++ mm/memfd.c | 61 +++- mm/shmem.c | 6 + security/security.c | 5 + tools/testing/selftests/memfd/fuse_test.c | 1 + tools/testing/selftests/memfd/memfd_test.c | 341 ++++++++++++++++++++- 13 files changed, 510 insertions(+), 3 deletions(-) create mode 100644 kernel/pid_sysctl.h base-commit: eb7081409f94a9a8608593d0fb63a1aa3d6f95d8 -- 2.39.0.rc1.256.g54fd8350bd-goog

2 weeks, 2 days

9
25
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[PATCH v2 00/16] selftests: vDSO: parse_vdso: Make compatible with nolibc

by Thomas Weißschuh

For testing the functionality of the vDSO, it is necessary to build userspace programs for multiple different architectures. It is additional work to acquire matching userspace cross-compilers with full C libraries and then building root images out of those. The kernel tree already contains nolibc, a small, header-only C library. By using it, it is possible to build userspace programs without any additional dependencies. For example the kernel.org crosstools or multi-target clang can be used to build test programs for a multitude of architectures. While nolibc is very limited, it is enough for many selftests. With some minor adjustments it is possible to make parse_vdso.c compatible with nolibc. As an example, vdso_standalone_test_x86 is now built from the same C code as the regular vdso_test_gettimeofday, while still being completely standalone. Also drop the dependency of parse_vdso.c on the elf.h header from libc and only use the one from the kernel's UAPI. While this series is useful on its own now, it will also integrate with the kunit UAPI framework currently under development: https://lore.kernel.org/lkml/20250217-kunit-kselftests-v1-0-42b4524c3b0a@li… Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> --- Changes in v2: - Provide a limits.h header in nolibc - Pick up Reviewed-by tags from Kees - Link to v1: https://lore.kernel.org/r/20250203-parse_vdso-nolibc-v1-0-9cb6268d77be@linu… --- Thomas Weißschuh (16): MAINTAINERS: Add vDSO selftests elf, uapi: Add definition for STN_UNDEF elf, uapi: Add definition for DT_GNU_HASH elf, uapi: Add definitions for VER_FLG_BASE and VER_FLG_WEAK elf, uapi: Add type ElfXX_Versym elf, uapi: Add types ElfXX_Verdef and ElfXX_Veraux tools/include: Add uapi/linux/elf.h selftests: Add headers target tools/nolibc: add limits.h shim header selftests: vDSO: vdso_standalone_test_x86: Use vdso_init_form_sysinfo_ehdr selftests: vDSO: parse_vdso: Drop vdso_init_from_auxv() selftests: vDSO: parse_vdso: Use UAPI headers instead of libc headers selftests: vDSO: parse_vdso: Test __SIZEOF_LONG__ instead of ULONG_MAX selftests: vDSO: vdso_test_gettimeofday: Clean up includes selftests: vDSO: vdso_test_gettimeofday: Make compatible with nolibc selftests: vDSO: vdso_standalone_test_x86: Switch to nolibc MAINTAINERS | 1 + include/uapi/linux/elf.h | 38 ++ tools/include/nolibc/Makefile | 1 + tools/include/nolibc/limits.h | 7 + tools/include/uapi/linux/elf.h | 524 +++++++++++++++++++++ tools/testing/selftests/lib.mk | 5 +- tools/testing/selftests/vDSO/Makefile | 11 +- tools/testing/selftests/vDSO/parse_vdso.c | 19 +- tools/testing/selftests/vDSO/parse_vdso.h | 1 - .../selftests/vDSO/vdso_standalone_test_x86.c | 143 +----- .../selftests/vDSO/vdso_test_gettimeofday.c | 4 +- 11 files changed, 590 insertions(+), 164 deletions(-) --- base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b change-id: 20241017-parse_vdso-nolibc-e069baa7ff48 Best regards, -- Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>

2 weeks, 5 days

7
42
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[PATCH v12] exec: Fix dead-lock in de_thread with ptrace_attach

by Bernd Edlinger

This introduces signal->exec_bprm, which is used to fix the case when at least one of the sibling threads is traced, and therefore the trace process may dead-lock in ptrace_attach, but de_thread will need to wait for the tracer to continue execution. The solution is to detect this situation and allow ptrace_attach to continue by temporarily releasing the cred_guard_mutex, while de_thread() is still waiting for traced zombies to be eventually released by the tracer. In the case of the thread group leader we only have to wait for the thread to become a zombie, which may also need co-operation from the tracer due to PTRACE_O_TRACEEXIT. When a tracer wants to ptrace_attach a task that already is in execve, we simply retry the ptrace_may_access check while temporarily installing the new credentials and dumpability which are about to be used after execve completes. If the ptrace_attach happens on a thread that is a sibling-thread of the thread doing execve, it is sufficient to check against the old credentials, as this thread will be waited for, before the new credentials are installed. Other threads die quickly since the cred_guard_mutex is released, but a deadly signal is already pending. In case the mutex_lock_killable misses the signal, the non-zero current->signal->exec_bprm makes sure they release the mutex immediately and return with -ERESTARTNOINTR. This means there is no API change, unlike the previous version of this patch which was discussed here: https://lore.kernel.org/lkml/b6537ae6-31b1-5c50-f32b-8b8332ace882@hotmail.d… See tools/testing/selftests/ptrace/vmaccess.c for a test case that gets fixed by this change. Note that since the test case was originally designed to test the ptrace_attach returning an error in this situation, the test expectation needed to be adjusted, to allow the API to succeed at the first attempt. Signed-off-by: Bernd Edlinger <bernd.edlinger(a)hotmail.de> --- fs/exec.c | 69 ++++++++++++++++------- fs/proc/base.c | 6 ++ include/linux/cred.h | 1 + include/linux/sched/signal.h | 18 ++++++ kernel/cred.c | 28 +++++++-- kernel/ptrace.c | 32 +++++++++++ kernel/seccomp.c | 12 +++- tools/testing/selftests/ptrace/vmaccess.c | 23 +++++--- 8 files changed, 155 insertions(+), 34 deletions(-) v10: Changes to previous version, make the PTRACE_ATTACH retun -EAGAIN, instead of execve return -ERESTARTSYS. Added some lessions learned to the description. v11: Check old and new credentials in PTRACE_ATTACH again without changing the API. Note: I got actually one response from an automatic checker to the v11 patch, https://lore.kernel.org/lkml/202107121344.wu68hEPF-lkp@intel.com/ which is complaining about: >> kernel/ptrace.c:425:26: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct cred const *old_cred @@ got struct cred const [noderef] __rcu *real_cred @@ 417 struct linux_binprm *bprm = task->signal->exec_bprm; 418 const struct cred *old_cred; 419 struct mm_struct *old_mm; 420 421 retval = down_write_killable(&task->signal->exec_update_lock); 422 if (retval) 423 goto unlock_creds; 424 task_lock(task); > 425 old_cred = task->real_cred; v12: Essentially identical to v11. - Fixed a minor merge conflict in linux v5.17, and fixed the above mentioned nit by adding __rcu to the declaration. - re-tested the patch with all linux versions from v5.11 to v6.6 v10 was an alternative approach which did imply an API change. But I would prefer to avoid such an API change. The difficult part is getting the right dumpability flags assigned before de_thread starts, hope you like this version. If not, the v10 is of course also acceptable. Thanks Bernd. diff --git a/fs/exec.c b/fs/exec.c index 2f2b0acec4f0..902d3b230485 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1041,11 +1041,13 @@ static int exec_mmap(struct mm_struct *mm) return 0; } -static int de_thread(struct task_struct *tsk) +static int de_thread(struct task_struct *tsk, struct linux_binprm *bprm) { struct signal_struct *sig = tsk->signal; struct sighand_struct *oldsighand = tsk->sighand; spinlock_t *lock = &oldsighand->siglock; + struct task_struct *t = tsk; + bool unsafe_execve_in_progress = false; if (thread_group_empty(tsk)) goto no_thread_group; @@ -1068,6 +1070,19 @@ static int de_thread(struct task_struct *tsk) if (!thread_group_leader(tsk)) sig->notify_count--; + while_each_thread(tsk, t) { + if (unlikely(t->ptrace) + && (t != tsk->group_leader || !t->exit_state)) + unsafe_execve_in_progress = true; + } + + if (unlikely(unsafe_execve_in_progress)) { + spin_unlock_irq(lock); + sig->exec_bprm = bprm; + mutex_unlock(&sig->cred_guard_mutex); + spin_lock_irq(lock); + } + while (sig->notify_count) { __set_current_state(TASK_KILLABLE); spin_unlock_irq(lock); @@ -1158,6 +1173,11 @@ static int de_thread(struct task_struct *tsk) release_task(leader); } + if (unlikely(unsafe_execve_in_progress)) { + mutex_lock(&sig->cred_guard_mutex); + sig->exec_bprm = NULL; + } + sig->group_exec_task = NULL; sig->notify_count = 0; @@ -1169,6 +1189,11 @@ static int de_thread(struct task_struct *tsk) return 0; killed: + if (unlikely(unsafe_execve_in_progress)) { + mutex_lock(&sig->cred_guard_mutex); + sig->exec_bprm = NULL; + } + /* protects against exit_notify() and __exit_signal() */ read_lock(&tasklist_lock); sig->group_exec_task = NULL; @@ -1253,6 +1278,24 @@ int begin_new_exec(struct linux_binprm * bprm) if (retval) return retval; + /* If the binary is not readable then enforce mm->dumpable=0 */ + would_dump(bprm, bprm->file); + if (bprm->have_execfd) + would_dump(bprm, bprm->executable); + + /* + * Figure out dumpability. Note that this checking only of current + * is wrong, but userspace depends on it. This should be testing + * bprm->secureexec instead. + */ + if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP || + is_dumpability_changed(current_cred(), bprm->cred) || + !(uid_eq(current_euid(), current_uid()) && + gid_eq(current_egid(), current_gid()))) + set_dumpable(bprm->mm, suid_dumpable); + else + set_dumpable(bprm->mm, SUID_DUMP_USER); + /* * Ensure all future errors are fatal. */ @@ -1261,7 +1304,7 @@ int begin_new_exec(struct linux_binprm * bprm) /* * Make this the only thread in the thread group. */ - retval = de_thread(me); + retval = de_thread(me, bprm); if (retval) goto out; @@ -1284,11 +1327,6 @@ int begin_new_exec(struct linux_binprm * bprm) if (retval) goto out; - /* If the binary is not readable then enforce mm->dumpable=0 */ - would_dump(bprm, bprm->file); - if (bprm->have_execfd) - would_dump(bprm, bprm->executable); - /* * Release all of the old mmap stuff */ @@ -1350,18 +1388,6 @@ int begin_new_exec(struct linux_binprm * bprm) me->sas_ss_sp = me->sas_ss_size = 0; - /* - * Figure out dumpability. Note that this checking only of current - * is wrong, but userspace depends on it. This should be testing - * bprm->secureexec instead. - */ - if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP || - !(uid_eq(current_euid(), current_uid()) && - gid_eq(current_egid(), current_gid()))) - set_dumpable(current->mm, suid_dumpable); - else - set_dumpable(current->mm, SUID_DUMP_USER); - perf_event_exec(); __set_task_comm(me, kbasename(bprm->filename), true); @@ -1480,6 +1506,11 @@ static int prepare_bprm_creds(struct linux_binprm *bprm) if (mutex_lock_interruptible(&current->signal->cred_guard_mutex)) return -ERESTARTNOINTR; + if (unlikely(current->signal->exec_bprm)) { + mutex_unlock(&current->signal->cred_guard_mutex); + return -ERESTARTNOINTR; + } + bprm->cred = prepare_exec_creds(); if (likely(bprm->cred)) return 0; diff --git a/fs/proc/base.c b/fs/proc/base.c index ffd54617c354..0da9adfadb48 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2788,6 +2788,12 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf, if (rv < 0) goto out_free; + if (unlikely(current->signal->exec_bprm)) { + mutex_unlock(&current->signal->cred_guard_mutex); + rv = -ERESTARTNOINTR; + goto out_free; + } + rv = security_setprocattr(PROC_I(inode)->op.lsm, file->f_path.dentry->d_name.name, page, count); diff --git a/include/linux/cred.h b/include/linux/cred.h index f923528d5cc4..b01e309f5686 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -159,6 +159,7 @@ extern const struct cred *get_task_cred(struct task_struct *); extern struct cred *cred_alloc_blank(void); extern struct cred *prepare_creds(void); extern struct cred *prepare_exec_creds(void); +extern bool is_dumpability_changed(const struct cred *, const struct cred *); extern int commit_creds(struct cred *); extern void abort_creds(struct cred *); extern const struct cred *override_creds(const struct cred *); diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h index 0014d3adaf84..14df7073a0a8 100644 --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -234,9 +234,27 @@ struct signal_struct { struct mm_struct *oom_mm; /* recorded mm when the thread group got * killed by the oom killer */ + struct linux_binprm *exec_bprm; /* Used to check ptrace_may_access + * against new credentials while + * de_thread is waiting for other + * traced threads to terminate. + * Set while de_thread is executing. + * The cred_guard_mutex is released + * after de_thread() has called + * zap_other_threads(), therefore + * a fatal signal is guaranteed to be + * already pending in the unlikely + * event, that + * current->signal->exec_bprm happens + * to be non-zero after the + * cred_guard_mutex was acquired. + */ + struct mutex cred_guard_mutex; /* guard against foreign influences on * credential calculations * (notably. ptrace) + * Held while execve runs, except when + * a sibling thread is being traced. * Deprecated do not use in new code. * Use exec_update_lock instead. */ diff --git a/kernel/cred.c b/kernel/cred.c index 98cb4eca23fb..586cb6c7cf6b 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -433,6 +433,28 @@ static bool cred_cap_issubset(const struct cred *set, const struct cred *subset) return false; } +/** + * is_dumpability_changed - Will changing creds from old to new + * affect the dumpability in commit_creds? + * + * Return: false - dumpability will not be changed in commit_creds. + * Return: true - dumpability will be changed to non-dumpable. + * + * @old: The old credentials + * @new: The new credentials + */ +bool is_dumpability_changed(const struct cred *old, const struct cred *new) +{ + if (!uid_eq(old->euid, new->euid) || + !gid_eq(old->egid, new->egid) || + !uid_eq(old->fsuid, new->fsuid) || + !gid_eq(old->fsgid, new->fsgid) || + !cred_cap_issubset(old, new)) + return true; + + return false; +} + /** * commit_creds - Install new credentials upon the current task * @new: The credentials to be assigned @@ -467,11 +489,7 @@ int commit_creds(struct cred *new) get_cred(new); /* we will require a ref for the subj creds too */ /* dumpability changes */ - if (!uid_eq(old->euid, new->euid) || - !gid_eq(old->egid, new->egid) || - !uid_eq(old->fsuid, new->fsuid) || - !gid_eq(old->fsgid, new->fsgid) || - !cred_cap_issubset(old, new)) { + if (is_dumpability_changed(old, new)) { if (task->mm) set_dumpable(task->mm, suid_dumpable); task->pdeath_signal = 0; diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 443057bee87c..eb1c450bb7d7 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -20,6 +20,7 @@ #include <linux/pagemap.h> #include <linux/ptrace.h> #include <linux/security.h> +#include <linux/binfmts.h> #include <linux/signal.h> #include <linux/uio.h> #include <linux/audit.h> @@ -435,6 +436,28 @@ static int ptrace_attach(struct task_struct *task, long request, if (retval) goto unlock_creds; + if (unlikely(task->in_execve)) { + struct linux_binprm *bprm = task->signal->exec_bprm; + const struct cred __rcu *old_cred; + struct mm_struct *old_mm; + + retval = down_write_killable(&task->signal->exec_update_lock); + if (retval) + goto unlock_creds; + task_lock(task); + old_cred = task->real_cred; + old_mm = task->mm; + rcu_assign_pointer(task->real_cred, bprm->cred); + task->mm = bprm->mm; + retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS); + rcu_assign_pointer(task->real_cred, old_cred); + task->mm = old_mm; + task_unlock(task); + up_write(&task->signal->exec_update_lock); + if (retval) + goto unlock_creds; + } + write_lock_irq(&tasklist_lock); retval = -EPERM; if (unlikely(task->exit_state)) @@ -508,6 +531,14 @@ static int ptrace_traceme(void) { int ret = -EPERM; + if (mutex_lock_interruptible(&current->signal->cred_guard_mutex)) + return -ERESTARTNOINTR; + + if (unlikely(current->signal->exec_bprm)) { + mutex_unlock(&current->signal->cred_guard_mutex); + return -ERESTARTNOINTR; + } + write_lock_irq(&tasklist_lock); /* Are we already being traced? */ if (!current->ptrace) { @@ -523,6 +554,7 @@ static int ptrace_traceme(void) } } write_unlock_irq(&tasklist_lock); + mutex_unlock(&current->signal->cred_guard_mutex); return ret; } diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 255999ba9190..b29bbfa0b044 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -1955,9 +1955,15 @@ static long seccomp_set_mode_filter(unsigned int flags, * Make sure we cannot change seccomp or nnp state via TSYNC * while another thread is in the middle of calling exec. */ - if (flags & SECCOMP_FILTER_FLAG_TSYNC && - mutex_lock_killable(&current->signal->cred_guard_mutex)) - goto out_put_fd; + if (flags & SECCOMP_FILTER_FLAG_TSYNC) { + if (mutex_lock_killable(&current->signal->cred_guard_mutex)) + goto out_put_fd; + + if (unlikely(current->signal->exec_bprm)) { + mutex_unlock(&current->signal->cred_guard_mutex); + goto out_put_fd; + } + } spin_lock_irq(&current->sighand->siglock); diff --git a/tools/testing/selftests/ptrace/vmaccess.c b/tools/testing/selftests/ptrace/vmaccess.c index 4db327b44586..3b7d81fb99bb 100644 --- a/tools/testing/selftests/ptrace/vmaccess.c +++ b/tools/testing/selftests/ptrace/vmaccess.c @@ -39,8 +39,15 @@ TEST(vmaccess) f = open(mm, O_RDONLY); ASSERT_GE(f, 0); close(f); - f = kill(pid, SIGCONT); - ASSERT_EQ(f, 0); + f = waitpid(-1, NULL, 0); + ASSERT_NE(f, -1); + ASSERT_NE(f, 0); + ASSERT_NE(f, pid); + f = waitpid(-1, NULL, 0); + ASSERT_EQ(f, pid); + f = waitpid(-1, NULL, 0); + ASSERT_EQ(f, -1); + ASSERT_EQ(errno, ECHILD); } TEST(attach) @@ -57,22 +64,24 @@ TEST(attach) sleep(1); k = ptrace(PTRACE_ATTACH, pid, 0L, 0L); - ASSERT_EQ(errno, EAGAIN); - ASSERT_EQ(k, -1); + ASSERT_EQ(k, 0); k = waitpid(-1, &s, WNOHANG); ASSERT_NE(k, -1); ASSERT_NE(k, 0); ASSERT_NE(k, pid); ASSERT_EQ(WIFEXITED(s), 1); ASSERT_EQ(WEXITSTATUS(s), 0); - sleep(1); - k = ptrace(PTRACE_ATTACH, pid, 0L, 0L); + k = waitpid(-1, &s, 0); + ASSERT_EQ(k, pid); + ASSERT_EQ(WIFSTOPPED(s), 1); + ASSERT_EQ(WSTOPSIG(s), SIGTRAP); + k = ptrace(PTRACE_CONT, pid, 0L, 0L); ASSERT_EQ(k, 0); k = waitpid(-1, &s, 0); ASSERT_EQ(k, pid); ASSERT_EQ(WIFSTOPPED(s), 1); ASSERT_EQ(WSTOPSIG(s), SIGSTOP); - k = ptrace(PTRACE_DETACH, pid, 0L, 0L); + k = ptrace(PTRACE_CONT, pid, 0L, 0L); ASSERT_EQ(k, 0); k = waitpid(-1, &s, 0); ASSERT_EQ(k, pid); -- 2.39.2

1 month, 2 weeks

7
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[PATCH v4 00/38] Mediated vPMU 4.0 for x86

by Mingwei Zhang

With joint effort from the upstream KVM community, we come up with the 4th version of mediated vPMU for x86. We have made the following changes on top of the previous RFC v3. v3 -> v4 - Rebase whole patchset on 6.14-rc3 base. - Address Peter's comments on Perf part. - Address Sean's comments on KVM part. * Change key word "passthrough" to "mediated" in all patches * Change static enabling to user space dynamic enabling via KVM_CAP_PMU_CAPABILITY. * Only support GLOBAL_CTRL save/restore with VMCS exec_ctrl, drop the MSR save/retore list support for GLOBAL_CTRL, thus the support of mediated vPMU is constrained to SapphireRapids and later CPUs on Intel side. * Merge some small changes into a single patch. - Address Sandipan's comment on invalid pmu pointer. - Add back "eventsel_hw" and "fixed_ctr_ctrl_hw" to avoid to directly manipulate pmc->eventsel and pmu->fixed_ctr_ctrl. Testing (Intel side): - Perf-based legacy vPMU (force emulation on/off) * Kselftests pmu_counters_test, pmu_event_filter_test and vmx_pmu_caps_test pass. * KUT PMU tests pmu, pmu_lbr, pmu_pebs pass. * Basic perf counting/sampling tests in 3 scenarios, guest-only, host-only and host-guest coexistence all pass. - Mediated vPMU (force emulation on/off) * Kselftests pmu_counters_test, pmu_event_filter_test and vmx_pmu_caps_test pass. * KUT PMU tests pmu, pmu_lbr, pmu_pebs pass. * Basic perf counting/sampling tests in 3 scenarios, guest-only, host-only and host-guest coexistence all pass. - Failures. All above tests passed on Intel Granite Rapids as well except a failure on KUT/pmu_pebs. * GP counter 0 (0xfffffffffffe): PEBS record (written seq 0) is verified (including size, counters and cfg). * The pebs_data_cfg (0xb500000000) doesn't match with the effective MSR_PEBS_DATA_CFG (0x0). * This failure has nothing to do with this mediated vPMU patch set. The failure is caused by Granite Rapids supported timed PEBS which needs extra support on Qemu and KUT/pmu_pebs. These extra support would be sent in separate patches later. Testing (AMD side): - Kselftests pmu_counters_test, pmu_event_filter_test and vmx_pmu_caps_test all pass - legacy guest with KUT/pmu: * qmeu option: -cpu host, -perfctr-core * when set force_emulation_prefix=1, passes * when set force_emulation_prefix=0, passes - perfmon-v1 guest with KUT/pmu: * qmeu option: -cpu host, -perfmon-v2 * when set force_emulation_prefix=1, passes * when set force_emulation_prefix=0, passes - perfmon-v2 guest with KUT/pmu: * qmeu option: -cpu host * when set force_emulation_prefix=1, passes * when set force_emulation_prefix=0, passes - perf_fuzzer (perfmon-v2): * fails with soft lockup in guest in current version. * culprit could be between 6.13 ~ 6.14-rc3 within KVM * Series tested on 6.12 and 6.13 without issue. Note: a QEMU series is needed to run mediated vPMU v4: - https://lore.kernel.org/all/20250324123712.34096-1-dapeng1.mi@linux.intel.c… History: - RFC v3: https://lore.kernel.org/all/20240801045907.4010984-1-mizhang@google.com/ - RFC v2: https://lore.kernel.org/all/20240506053020.3911940-1-mizhang@google.com/ - RFC v1: https://lore.kernel.org/all/20240126085444.324918-1-xiong.y.zhang@linux.int… Dapeng Mi (18): KVM: x86/pmu: Introduce enable_mediated_pmu global parameter KVM: x86/pmu: Check PMU cpuid configuration from user space KVM: x86: Rename vmx_vmentry/vmexit_ctrl() helpers KVM: x86/pmu: Add perf_capabilities field in struct kvm_host_values{} KVM: x86/pmu: Move PMU_CAP_{FW_WRITES,LBR_FMT} into msr-index.h header KVM: VMX: Add macros to wrap around {secondary,tertiary}_exec_controls_changebit() KVM: x86/pmu: Check if mediated vPMU can intercept rdpmc KVM: x86/pmu/vmx: Save/load guest IA32_PERF_GLOBAL_CTRL with vm_exit/entry_ctrl KVM: x86/pmu: Optimize intel/amd_pmu_refresh() helpers KVM: x86/pmu: Setup PMU MSRs' interception mode KVM: x86/pmu: Handle PMU MSRs interception and event filtering KVM: x86/pmu: Switch host/guest PMU context at vm-exit/vm-entry KVM: x86/pmu: Handle emulated instruction for mediated vPMU KVM: nVMX: Add macros to simplify nested MSR interception setting KVM: selftests: Add mediated vPMU supported for pmu tests KVM: Selftests: Support mediated vPMU for vmx_pmu_caps_test KVM: Selftests: Fix pmu_counters_test error for mediated vPMU KVM: x86/pmu: Expose enable_mediated_pmu parameter to user space Kan Liang (8): perf: Support get/put mediated PMU interfaces perf: Skip pmu_ctx based on event_type perf: Clean up perf ctx time perf: Add a EVENT_GUEST flag perf: Add generic exclude_guest support perf: Add switch_guest_ctx() interface perf/x86: Support switch_guest_ctx interface perf/x86/intel: Support PERF_PMU_CAP_MEDIATED_VPMU Mingwei Zhang (5): perf/x86: Forbid PMI handler when guest own PMU perf/x86/core: Plumb mediated PMU capability from x86_pmu to x86_pmu_cap KVM: x86/pmu: Exclude PMU MSRs in vmx_get_passthrough_msr_slot() KVM: x86/pmu: introduce eventsel_hw to prepare for pmu event filtering KVM: nVMX: Add nested virtualization support for mediated PMU Sandipan Das (4): perf/x86/core: Do not set bit width for unavailable counters KVM: x86/pmu: Add AMD PMU registers to direct access list KVM: x86/pmu/svm: Set GuestOnly bit and clear HostOnly bit when guest write to event selectors perf/x86/amd: Support PERF_PMU_CAP_MEDIATED_VPMU for AMD host Xiong Zhang (3): x86/irq: Factor out common code for installing kvm irq handler perf: core/x86: Register a new vector for KVM GUEST PMI KVM: x86/pmu: Register KVM_GUEST_PMI_VECTOR handler arch/x86/events/amd/core.c | 2 + arch/x86/events/core.c | 40 +- arch/x86/events/intel/core.c | 5 + arch/x86/include/asm/hardirq.h | 1 + arch/x86/include/asm/idtentry.h | 1 + arch/x86/include/asm/irq.h | 2 +- arch/x86/include/asm/irq_vectors.h | 5 +- arch/x86/include/asm/kvm-x86-pmu-ops.h | 2 + arch/x86/include/asm/kvm_host.h | 10 + arch/x86/include/asm/msr-index.h | 18 +- arch/x86/include/asm/perf_event.h | 1 + arch/x86/include/asm/vmx.h | 1 + arch/x86/kernel/idt.c | 1 + arch/x86/kernel/irq.c | 39 +- arch/x86/kvm/cpuid.c | 15 + arch/x86/kvm/pmu.c | 254 ++++++++- arch/x86/kvm/pmu.h | 45 ++ arch/x86/kvm/svm/pmu.c | 148 ++++- arch/x86/kvm/svm/svm.c | 26 + arch/x86/kvm/svm/svm.h | 2 +- arch/x86/kvm/vmx/capabilities.h | 11 +- arch/x86/kvm/vmx/nested.c | 68 ++- arch/x86/kvm/vmx/pmu_intel.c | 224 ++++++-- arch/x86/kvm/vmx/vmx.c | 89 +-- arch/x86/kvm/vmx/vmx.h | 11 +- arch/x86/kvm/x86.c | 63 ++- arch/x86/kvm/x86.h | 2 + include/linux/perf_event.h | 47 +- kernel/events/core.c | 519 ++++++++++++++---- .../beauty/arch/x86/include/asm/irq_vectors.h | 5 +- .../selftests/kvm/include/kvm_test_harness.h | 13 + .../testing/selftests/kvm/include/kvm_util.h | 3 + .../selftests/kvm/include/x86/processor.h | 8 + tools/testing/selftests/kvm/lib/kvm_util.c | 23 + .../selftests/kvm/x86/pmu_counters_test.c | 24 +- .../selftests/kvm/x86/pmu_event_filter_test.c | 8 +- .../selftests/kvm/x86/vmx_pmu_caps_test.c | 2 +- 37 files changed, 1480 insertions(+), 258 deletions(-) base-commit: 0ad2507d5d93f39619fc42372c347d6006b64319 -- 2.49.0.395.g12beb8f557-goog

2 months

8
126
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[PATCH v2 0/5] KVM: Improve VMware guest support

by Zack Rusin

This is the second version of a series that lets us run VMware Workstation on Linux on top of KVM. The most significant change in this series is the introduction of CONFIG_KVM_VMWARE which is, in general, a nice cleanup for various bits of VMware compatibility code that have been scattered around KVM. (first patch) The rest of the series builds upon the VMware platform to implement features that are needed to run VMware guests without any modifications on top of KVM: - ability to turn on the VMware backdoor at runtime on a per-vm basis (used to be a kernel boot argument only) - support for VMware hypercalls - VMware products have a huge collection of hypercalls, all of which are handled in userspace, - support for handling legacy VMware backdoor in L0 in nested configs - in cases where we have WS running a Windows VBS guest, the L0 would be KVM, L1 Hyper-V so by default VMware Tools backdoor calls endup in Hyper-V which can not handle them, so introduce a cap to let L0 handle those. The final change in the series is a kselftest of the VMware hypercall functionality. Cc: Paolo Bonzini <pbonzini(a)redhat.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Sean Christopherson <seanjc(a)google.com> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: x86(a)kernel.org Cc: "H. Peter Anvin" <hpa(a)zytor.com> Cc: Zack Rusin <zack.rusin(a)broadcom.com> Cc: Doug Covelli <doug.covelli(a)broadcom.com> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Namhyung Kim <namhyung(a)kernel.org> Cc: Arnaldo Carvalho de Melo <acme(a)redhat.com> Cc: Michael Ellerman <mpe(a)ellerman.id.au> Cc: Joel Stanley <joel(a)jms.id.au> Cc: Isaku Yamahata <isaku.yamahata(a)intel.com> Cc: kvm(a)vger.kernel.org Cc: linux-doc(a)vger.kernel.org Cc: linux-kernel(a)vger.kernel.org Cc: linux-kselftest(a)vger.kernel.org Zack Rusin (5): KVM: x86: Centralize KVM's VMware code KVM: x86: Allow enabling of the vmware backdoor via a cap KVM: x86: Add support for VMware guest specific hypercalls KVM: x86: Add support for legacy VMware backdoors in nested setups KVM: selftests: x86: Add a test for KVM_CAP_X86_VMWARE_HYPERCALL Documentation/virt/kvm/api.rst | 86 +++++++- MAINTAINERS | 9 + arch/x86/include/asm/kvm_host.h | 13 ++ arch/x86/kvm/Kconfig | 16 ++ arch/x86/kvm/Makefile | 1 + arch/x86/kvm/emulate.c | 11 +- arch/x86/kvm/kvm_vmware.c | 85 ++++++++ arch/x86/kvm/kvm_vmware.h | 189 ++++++++++++++++++ arch/x86/kvm/pmu.c | 39 +--- arch/x86/kvm/pmu.h | 4 - arch/x86/kvm/svm/nested.c | 6 + arch/x86/kvm/svm/svm.c | 10 +- arch/x86/kvm/vmx/nested.c | 6 + arch/x86/kvm/vmx/vmx.c | 5 +- arch/x86/kvm/x86.c | 74 +++---- arch/x86/kvm/x86.h | 2 - include/uapi/linux/kvm.h | 27 +++ tools/include/uapi/linux/kvm.h | 3 + tools/testing/selftests/kvm/Makefile.kvm | 1 + .../selftests/kvm/x86/vmware_hypercall_test.c | 121 +++++++++++ 20 files changed, 614 insertions(+), 94 deletions(-) create mode 100644 arch/x86/kvm/kvm_vmware.c create mode 100644 arch/x86/kvm/kvm_vmware.h create mode 100644 tools/testing/selftests/kvm/x86/vmware_hypercall_test.c -- 2.48.1

2 months, 2 weeks

2
2
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[PATCH/RFC] kunit/rtc: Add real support for very slow tests

by Geert Uytterhoeven

When running rtc_lib_test ("lib_test" before my "[PATCH] rtc: Rename lib_test to rtc_lib_test") on m68k/ARAnyM: KTAP version 1 1..1 KTAP version 1 # Subtest: rtc_lib_test_cases # module: rtc_lib_test 1..2 # rtc_time64_to_tm_test_date_range_1000: Test should be marked slow (runtime: 3.222371420s) ok 1 rtc_time64_to_tm_test_date_range_1000 # rtc_time64_to_tm_test_date_range_160000: try timed out # rtc_time64_to_tm_test_date_range_160000: test case timed out # rtc_time64_to_tm_test_date_range_160000.speed: slow not ok 2 rtc_time64_to_tm_test_date_range_160000 # rtc_lib_test_cases: pass:1 fail:1 skip:0 total:2 # Totals: pass:1 fail:1 skip:0 total:2 not ok 1 rtc_lib_test_cases Commit 02c2d0c2a84172c3 ("kunit: Add speed attribute") added the notion of "very slow" tests, but this is further unused and unhandled. Hence: 1. Introduce KUNIT_CASE_VERY_SLOW(), 2. Increase timeout by ten; ideally this should only be done for very slow tests, but I couldn't find how to access kunit_case.attr.case from kunit_try_catch_run(), 3. Mark rtc_time64_to_tm_test_date_range_1000 slow, 4. Mark rtc_time64_to_tm_test_date_range_160000 very slow. Afterwards: KTAP version 1 1..1 KTAP version 1 # Subtest: rtc_lib_test_cases # module: rtc_lib_test 1..2 # rtc_time64_to_tm_test_date_range_1000.speed: slow ok 1 rtc_time64_to_tm_test_date_range_1000 # rtc_time64_to_tm_test_date_range_160000.speed: very_slow ok 2 rtc_time64_to_tm_test_date_range_160000 # rtc_lib_test_cases: pass:2 fail:0 skip:0 total:2 # Totals: pass:2 fail:0 skip:0 total:2 ok 1 rtc_lib_test_cases Signed-off-by: Geert Uytterhoeven <geert(a)linux-m68k.org> --- drivers/rtc/rtc_lib_test.c | 4 ++-- include/kunit/test.h | 11 +++++++++++ lib/kunit/try-catch.c | 3 ++- 3 files changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/rtc/rtc_lib_test.c b/drivers/rtc/rtc_lib_test.c index c30c759662e39b48..fd3210e39d37dbc6 100644 --- a/drivers/rtc/rtc_lib_test.c +++ b/drivers/rtc/rtc_lib_test.c @@ -85,8 +85,8 @@ static void rtc_time64_to_tm_test_date_range_1000(struct kunit *test) } static struct kunit_case rtc_lib_test_cases[] = { - KUNIT_CASE(rtc_time64_to_tm_test_date_range_1000), - KUNIT_CASE_SLOW(rtc_time64_to_tm_test_date_range_160000), + KUNIT_CASE_SLOW(rtc_time64_to_tm_test_date_range_1000), + KUNIT_CASE_VERY_SLOW(rtc_time64_to_tm_test_date_range_160000), {} }; diff --git a/include/kunit/test.h b/include/kunit/test.h index 9b773406e01f3c43..4e3c1cae5b41466e 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -183,6 +183,17 @@ static inline char *kunit_status_to_ok_not_ok(enum kunit_status status) { .run_case = test_name, .name = #test_name, \ .attr.speed = KUNIT_SPEED_SLOW, .module_name = KBUILD_MODNAME} +/** + * KUNIT_CASE_VERY_SLOW - A helper for creating a &struct kunit_case + * with the very slow attribute + * + * @test_name: a reference to a test case function. + */ + +#define KUNIT_CASE_VERY_SLOW(test_name) \ + { .run_case = test_name, .name = #test_name, \ + .attr.speed = KUNIT_SPEED_VERY_SLOW, .module_name = KBUILD_MODNAME} + /** * KUNIT_CASE_PARAM - A helper for creation a parameterized &struct kunit_case * diff --git a/lib/kunit/try-catch.c b/lib/kunit/try-catch.c index 6bbe0025b0790bd2..92099c67bb21d0a4 100644 --- a/lib/kunit/try-catch.c +++ b/lib/kunit/try-catch.c @@ -56,7 +56,8 @@ static unsigned long kunit_test_timeout(void) * If tests timeout due to exceeding sysctl_hung_task_timeout_secs, * the task will be killed and an oops generated. */ - return 300 * msecs_to_jiffies(MSEC_PER_SEC); /* 5 min */ + // FIXME times ten for KUNIT_SPEED_VERY_SLOW? + return 10 * 300 * msecs_to_jiffies(MSEC_PER_SEC); /* 5 min */ } void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context) -- 2.43.0

2 months, 2 weeks

3
3
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[PATCH v3 0/6] KVM: guest_memfd: support for uffd minor

by Nikita Kalyazin

This series is built on top of the Fuad's v7 "mapping guest_memfd backed memory at the host" [1]. With James's KVM userfault [2], it is possible to handle stage-2 faults in guest_memfd in userspace. However, KVM itself also triggers faults in guest_memfd in some cases, for example: PV interfaces like kvmclock, PV EOI and page table walking code when fetching the MMIO instruction on x86. It was agreed in the guest_memfd upstream call on 23 Jan 2025 [3] that KVM would be accessing those pages via userspace page tables. In order for such faults to be handled in userspace, guest_memfd needs to support userfaultfd. Changes since v2 [4]: - James: Fix sgp type when calling shmem_get_folio_gfp - James: Improved vm_ops->fault() error handling - James: Add and make use of the can_userfault() VMA operation - James: Add UFFD_FEATURE_MINOR_GUEST_MEMFD feature flag - James: Fix typos and add more checks in the test Nikita [1] https://lore.kernel.org/kvm/20250318161823.4005529-1-tabba@google.com/T/ [2] https://lore.kernel.org/kvm/20250109204929.1106563-1-jthoughton@google.com/… [3] https://docs.google.com/document/d/1M6766BzdY1Lhk7LiR5IqVR8B8mG3cr-cxTxOrAo… [4] https://lore.kernel.org/kvm/20250402160721.97596-1-kalyazin@amazon.com/T/ Nikita Kalyazin (6): mm: userfaultfd: generic continue for non hugetlbfs mm: provide can_userfault vma operation mm: userfaultfd: use can_userfault vma operation KVM: guest_memfd: add support for userfaultfd minor mm: userfaultfd: add UFFD_FEATURE_MINOR_GUEST_MEMFD KVM: selftests: test userfaultfd minor for guest_memfd fs/userfaultfd.c | 3 +- include/linux/mm.h | 5 + include/linux/mm_types.h | 4 + include/linux/userfaultfd_k.h | 10 +- include/uapi/linux/userfaultfd.h | 8 +- mm/hugetlb.c | 9 +- mm/shmem.c | 17 +++- mm/userfaultfd.c | 47 ++++++--- .../testing/selftests/kvm/guest_memfd_test.c | 99 +++++++++++++++++++ virt/kvm/guest_memfd.c | 10 ++ 10 files changed, 188 insertions(+), 24 deletions(-) base-commit: 3cc51efc17a2c41a480eed36b31c1773936717e0 -- 2.47.1

3 months, 2 weeks

7
27
0 0

[PATCH] kunit: qemu_configs: Add riscv32 config

by Thomas Weißschuh

Add a basic config to run kunit tests on riscv32. Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> --- tools/testing/kunit/qemu_configs/riscv32.py | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/tools/testing/kunit/qemu_configs/riscv32.py b/tools/testing/kunit/qemu_configs/riscv32.py new file mode 100644 index 0000000000000000000000000000000000000000..b79ba0ae30f8573035b3401be337b379eba97e26 --- /dev/null +++ b/tools/testing/kunit/qemu_configs/riscv32.py @@ -0,0 +1,17 @@ +# SPDX-License-Identifier: GPL-2.0 + +from ..qemu_config import QemuArchParams + +QEMU_ARCH = QemuArchParams(linux_arch='riscv', + kconfig=''' +CONFIG_NONPORTABLE=y +CONFIG_ARCH_RV32I=y +CONFIG_ARCH_VIRT=y +CONFIG_SERIAL_8250=y +CONFIG_SERIAL_8250_CONSOLE=y +CONFIG_SERIAL_OF_PLATFORM=y +''', + qemu_arch='riscv32', + kernel_path='arch/riscv/boot/Image', + kernel_command_line='console=ttyS0', + extra_qemu_params=['-machine', 'virt']) --- base-commit: 0af2f6be1b4281385b618cb86ad946eded089ac8 change-id: 20250214-kunit-qemu-riscv32-fb38d659c373 Best regards, -- Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>

3 months, 4 weeks

3
2
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[PATCH v10 0/6] rust: reduce `as` casts, enable related lints

by Tamir Duberstein

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. As a later addition, `clippy::cast_lossless` and `clippy::ref_as_ptr` are also enabled. This series depends on "rust: retain pointer mut-ness in `container_of!`"[1]. Link: https://lore.kernel.org/all/20250409-container-of-mutness-v1-1-64f472b94534… [1] Signed-off-by: Tamir Duberstein <tamird(a)gmail.com> --- Changes in v10: - Move fragment from "rust: enable `clippy::ptr_cast_constness` lint" to "rust: enable `clippy::ptr_as_ptr` lint". (Boqun Feng) - Replace `(...).into()` with `T::from(...)` where the destination type isn't obvious in "rust: enable `clippy::cast_lossless` lint". (Boqun Feng) - Link to v9: https://lore.kernel.org/r/20250416-ptr-as-ptr-v9-0-18ec29b1b1f3@gmail.com Changes in v9: - Replace ref-to-ptr coercion using `let` bindings with `core::ptr::from_{ref,mut}`. (Boqun Feng). - Link to v8: https://lore.kernel.org/r/20250409-ptr-as-ptr-v8-0-3738061534ef@gmail.com Changes in v8: - Use coercion to go ref -> ptr. - rustfmt. - Rebase on v6.15-rc1. - Extract first commit to its own series as it is shared with other series. - Link to v7: https://lore.kernel.org/r/20250325-ptr-as-ptr-v7-0-87ab452147b9@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 (6): 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 | 2 +- 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 | 6 +++--- rust/kernel/device.rs | 4 ++-- rust/kernel/device_id.rs | 4 ++-- 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 | 2 +- rust/kernel/io.rs | 18 +++++++++--------- rust/kernel/kunit.rs | 11 +++++++---- 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 | 11 +++++++---- rust/kernel/platform.rs | 4 +++- rust/kernel/print.rs | 6 +++--- rust/kernel/seq_file.rs | 2 +- rust/kernel/str.rs | 14 +++++++------- rust/kernel/sync/poll.rs | 2 +- rust/kernel/time/hrtimer/pin.rs | 2 +- rust/kernel/time/hrtimer/pin_mut.rs | 2 +- rust/kernel/uaccess.rs | 4 ++-- rust/kernel/workqueue.rs | 12 ++++++------ rust/uapi/lib.rs | 3 +++ 31 files changed, 96 insertions(+), 74 deletions(-) --- base-commit: 0af2f6be1b4281385b618cb86ad946eded089ac8 change-id: 20250307-ptr-as-ptr-21b1867fc4d4 prerequisite-change-id: 20250409-container-of-mutness-b153dab4388d:v1 prerequisite-patch-id: 53d5889db599267f87642bb0ae3063c29bc24863 Best regards, -- Tamir Duberstein <tamird(a)gmail.com>

3 months, 4 weeks

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[PATCH RFC bpf-next 0/4] bpf, arm64: support up to 12 arguments

by Alexis Lothoré (eBPF Foundation)

Hello, this series is a revival of Xu Kuhoai's work to enable larger arguments count for BPF programs on ARM64 ([1]). His initial series received some positive feedback, but lacked some specific case handling around arguments alignment (see AAPCS64 C.14 rule in section 6.8.2, [2]). There as been another attempt from Puranjay Mohan, which was unfortunately missing the same thing ([3]). Since there has been some time between those series and this new one, I chose to send it as a new series rather than a new revision of the existing series. To support the increased argument counts and arguments larger than registers size (eg: structures), the trampoline does the following: - for bpf programs: arguments are retrieved from both registers and the function stack, and pushed in the trampoline stack as an array of u64 to generate the programs context. It is then passed by pointer to the bpf programs - when the trampoline is in charge of calling the original function: it restores the registers content, and generates a new stack layout for the additional arguments that do not fit in registers. This new attempt is based on Xu's series and aims to handle the missing alignment concern raised in the reviews discussions. The main novelties are then around arguments alignments: - the first commit is exposing some new info in the BTF function model passed to the JIT compiler to allow it to deduce the needed alignment when configuring the trampoline stack - the second commit is taken from Xu's series, and received the following modifications: - the calc_aux_args computes an expected alignment for each argument - the calc_aux_args computes two different stack space sizes: the one needed to store the bpf programs context, and the original function stacked arguments (which needs alignment). Those stack sizes are in bytes instead of "slots" - when saving/restoring arguments for bpf program or for the original function, make sure to align the load/store accordingly, when relevant - a few typos fixes and some rewording, raised by the review on the original series - the last commit introduces some explicit tests that ensure that the needed alignment is enforced by the trampoline I marked the series as RFC because it appears that the new tests trigger some failures in CI on x86 and s390, despite the series not touching any code related to those architectures. Some very early investigation/gdb debugging on the x86 side seems to hint that it could be related to the same missing alignment too (based on section 3.2.3 in [4], and so the x86 trampoline would need the same alignment handling ?). For s390 it looks less clear, as all values captured from the bpf test program are set to 0 in the CI output, and I don't have the proper setup yet to check the low level details. I am tempted to isolate those new tests (which were actually useful to spot real issues while tuning the ARM64 trampoline) and add them to the relevant DENYLIST files for x86/s390, but I guess this is not the right direction, so I would gladly take a second opinion on this. [1] https://lore.kernel.org/all/20230917150752.69612-1-xukuohai@huaweicloud.com… [2] https://github.com/ARM-software/abi-aa/blob/main/aapcs64/aapcs64.rst#id82 [3] https://lore.kernel.org/bpf/20240705125336.46820-1-puranjay@kernel.org/ [4] https://refspecs.linuxbase.org/elf/x86_64-abi-0.99.pdf Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore(a)bootlin.com> --- Alexis Lothoré (eBPF Foundation) (3): bpf: add struct largest member size in func model bpf/selftests: add tests to validate proper arguments alignment on ARM64 bpf/selftests: enable tracing tests for ARM64 Xu Kuohai (1): bpf, arm64: Support up to 12 function arguments arch/arm64/net/bpf_jit_comp.c | 235 ++++++++++++++++----- include/linux/bpf.h | 1 + kernel/bpf/btf.c | 25 +++ tools/testing/selftests/bpf/DENYLIST.aarch64 | 3 - .../selftests/bpf/prog_tests/tracing_struct.c | 23 ++ tools/testing/selftests/bpf/progs/tracing_struct.c | 10 +- .../selftests/bpf/progs/tracing_struct_many_args.c | 67 ++++++ .../testing/selftests/bpf/test_kmods/bpf_testmod.c | 50 +++++ 8 files changed, 357 insertions(+), 57 deletions(-) --- base-commit: 91e7eb701b4bc389e7ddfd80ef6e82d1a6d2d368 change-id: 20250220-many_args_arm64-8bd3747e6948 Best regards, -- Alexis Lothoré, Bootlin Embedded Linux and Kernel engineering https://bootlin.com

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Linux-kselftest-mirror April 2025