kernel/linux.git/tools/testing/selftests/kvm/rseq_test.c, branch v6.18.21

KVM: selftests: Add missing "break" in rseq_test's param parsing

2026-01-02T11:57:22+00:00

commit 1b9439c933b500cb24710bbd81fe56e9b0025b6f upstream. In commit 0297cdc12a87 ("KVM: selftests: Add option to rseq test to override /dev/cpu_dma_latency"), a 'break' is missed before the option 'l' in the argument parsing loop, which leads to an unexpected core dump in atoi_paranoid(). It tries to get the latency from non-existent argument. host$ ./rseq_test -u Random seed: 0x6b8b4567 Segmentation fault (core dumped) Add a 'break' before the option 'l' in the argument parsing loop to avoid the unexpected core dump. Fixes: 0297cdc12a87 ("KVM: selftests: Add option to rseq test to override /dev/cpu_dma_latency") Cc: stable@vger.kernel.org # v6.15+ Signed-off-by: Gavin Shan Link: https://patch.msgid.link/20251124050427.1924591-1-gshan@redhat.com [sean: describe code change in shortlog] Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

KVM: selftests: Add option to rseq test to override /dev/cpu_dma_latency

2025-04-04T11:07:39+00:00

Add a "-l " param to the rseq test so that the user can override /dev/cpu_dma_latency, as described by the test's suggested workaround for not being able to complete enough migrations. cpu_dma_latency is not a normal file, even as far as procfs files go. Writes to cpu_dma_latency only persist so long as the file is open, e.g. so that the kernel automatically reverts back to a power-optimized state once the sensitive workload completes. Provide the necessary functionality instead of effectively forcing the user to write a non-obvious wrapper. Cc: Dongsheng Zhang Cc: Zide Chen Signed-off-by: Sean Christopherson Message-ID: <20250401142238.819487-1-seanjc@google.com> Signed-off-by: Paolo Bonzini

Merge tag 'kvm-x86-selftests_utils-6.10' of https://github.com/kvm-x86/linux into HEAD

2024-05-12T07:18:11+00:00

KVM selftests treewide updates for 6.10: - Define _GNU_SOURCE for all selftests to fix a warning that was introduced by a change to kselftest_harness.h late in the 6.9 cycle, and because forcing every test to #define _GNU_SOURCE is painful. - Provide a global psuedo-RNG instance for all tests, so that library code can generate random, but determinstic numbers. - Use the global pRNG to randomly force emulation of select writes from guest code on x86, e.g. to help validate KVM's emulation of locked accesses. - Rename kvm_util_base.h back to kvm_util.h, as the weird layer of indirection was added purely to avoid manually #including ucall_common.h in a handful of locations. - Allocate and initialize x86's GDT, IDT, TSS, segments, and default exception handlers at VM creation, instead of forcing tests to manually trigger the related setup.

KVM: selftests: Allow skipping the KVM_RUN sanity check in rseq_test

2024-05-02T23:12:27+00:00

The rseq test's migration worker delays 1-10 us, assuming that one KVM_RUN iteration only takes a few microseconds. But if the CPU low power wakeup latency is large enough, for example, hundreds or even thousands of microseconds for deep C-state exit latencies on x86 server CPUs, it may happen that the target CPU is unable to wakeup and run the vCPU before the migration worker starts to migrate the vCPU thread to the _next_ CPU. If the system workload is light, most CPUs could be at a certain low power state, which may result in less successful migrations and fail the migration/KVM_RUN ratio sanity check. But this is not supposed to be deemed a test failure. Add a command line option to skip the sanity check, along with a comment and a verbose assert message to try to help the user resolve the potential source of failures without having to resort to disabling the check. Co-developed-by: Dongsheng Zhang Signed-off-by: Dongsheng Zhang Signed-off-by: Zide Chen Link: https://lore.kernel.org/r/20240502213936.27619-1-zide.chen@intel.com [sean: massage changelog] Signed-off-by: Sean Christopherson

Revert "kvm: selftests: move base kvm_util.h declarations to kvm_util_base.h"

2024-04-29T19:54:13+00:00

Effectively revert the movement of code from kvm_util.h => kvm_util_base.h, as the TL;DR of the justification for the move was to avoid #idefs and/or circular dependencies between what ended up being ucall_common.h and what was (and now again, is), kvm_util.h. But avoiding #ifdef and circular includes is trivial: don't do that. The cost of removing kvm_util_base.h is a few extra includes of ucall_common.h, but that cost is practically nothing. On the other hand, having a "base" version of a header that is really just the header itself is confusing, and makes it weird/hard to choose names for headers that actually are "base" headers, e.g. to hold core KVM selftests typedefs. For all intents and purposes, this reverts commit 7d9a662ed9f0403e7b94940dceb81552b8edb931. Reviewed-by: Ackerley Tng Link: https://lore.kernel.org/r/20240314232637.2538648-2-seanjc@google.com Signed-off-by: Sean Christopherson

KVM: selftests: Define _GNU_SOURCE for all selftests code

2024-04-29T19:49:10+00:00

Define _GNU_SOURCE is the base CFLAGS instead of relying on selftests to manually #define _GNU_SOURCE, which is repetitive and error prone. E.g. kselftest_harness.h requires _GNU_SOURCE for asprintf(), but if a selftest includes kvm_test_harness.h after stdio.h, the include guards result in the effective version of stdio.h consumed by kvm_test_harness.h not defining asprintf(): In file included from x86_64/fix_hypercall_test.c:12: In file included from include/kvm_test_harness.h:11: ../kselftest_harness.h:1169:2: error: call to undeclared function 'asprintf'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 1169 | asprintf(&test_name, "%s%s%s.%s", f->name, | ^ When including the rseq selftest's "library" code, #undef _GNU_SOURCE so that rseq.c controls whether or not it wants to build with _GNU_SOURCE. Reported-by: Muhammad Usama Anjum Acked-by: Claudio Imbrenda Acked-by: Oliver Upton Acked-by: Anup Patel Reviewed-by: Muhammad Usama Anjum Link: https://lore.kernel.org/r/20240423190308.2883084-1-seanjc@google.com Signed-off-by: Sean Christopherson

KVM: selftests: Remove redundant newlines

2024-01-29T16:39:14+00:00

TEST_* functions append their own newline. Remove newlines from TEST_* callsites to avoid extra newlines in output. Signed-off-by: Andrew Jones Link: https://lore.kernel.org/r/20231206170241.82801-8-ajones@ventanamicro.com Signed-off-by: Sean Christopherson

KVM: selftests: Fix build of rseq test

2023-01-30T15:29:45+00:00

The KVM rseq test is failing to build in -next due to a commit merged from the tip tree which adds a wrapper for sys_getcpu() to the rseq kselftests, conflicting with the wrapper already included in the KVM selftest: rseq_test.c:48:13: error: conflicting types for 'sys_getcpu' 48 | static void sys_getcpu(unsigned *cpu) | ^~~~~~~~~~ In file included from rseq_test.c:23: ../rseq/rseq.c:82:12: note: previous definition of 'sys_getcpu' was here 82 | static int sys_getcpu(unsigned *cpu, unsigned *node) | ^~~~~~~~~~ Fix this by removing the local wrapper and moving the result check up to the caller. Fixes: 99babd04b250 ("selftests/rseq: Implement rseq numa node id field selftest") Signed-off-by: Mark Brown Signed-off-by: Peter Zijlstra (Intel) Acked-by: Mathieu Desnoyers Link: https://lore.kernel.org/r/20230106-fix-kvm-rseq-build-v1-1-b704d9831d02@kernel.org

KVM: selftests: move common startup logic to kvm_util.c

2022-11-17T00:58:56+00:00

Consolidate common startup logic in one place by implementing a single setup function with __attribute((constructor)) for all selftests within kvm_util.c. This allows moving logic like: /* Tell stdout not to buffer its content */ setbuf(stdout, NULL); to a single file for all selftests. This will also allow any required setup at entry in future to be done in common main function. Link: https://lore.kernel.org/lkml/Ywa9T+jKUpaHLu%2Fl@google.com Suggested-by: Sean Christopherson Reviewed-by: Andrew Jones Reviewed-by: Peter Gonda Signed-off-by: Vishal Annapurve Link: https://lore.kernel.org/r/20221115213845.3348210-2-vannapurve@google.com Signed-off-by: Sean Christopherson

KVM: selftests: Automatically do init_ucall() for non-barebones VMs

2022-11-17T00:58:51+00:00

Do init_ucall() automatically during VM creation to kill two (three?) birds with one stone. First, initializing ucall immediately after VM creations allows forcing aarch64's MMIO ucall address to immediately follow memslot0. This is still somewhat fragile as tests could clobber the MMIO address with a new memslot, but it's safe-ish since tests have to be conversative when accounting for memslot0. And this can be hardened in the future by creating a read-only memslot for the MMIO page (KVM ARM exits with MMIO if the guest writes to a read-only memslot). Add a TODO to document that selftests can and should use a memslot for the ucall MMIO (doing so requires yet more rework because tests assumes thay can use all memslots except memslot0). Second, initializing ucall for all VMs prepares for making ucall initialization meaningful on all architectures. aarch64 is currently the only arch that needs to do any setup, but that will change in the future by switching to a pool-based implementation (instead of the current stack-based approach). Lastly, defining the ucall MMIO address from common code will simplify switching all architectures (except s390) to a common MMIO-based ucall implementation (if there's ever sufficient motivation to do so). Cc: Oliver Upton Reviewed-by: Andrew Jones Tested-by: Peter Gonda Signed-off-by: Sean Christopherson Link: https://lore.kernel.org/r/20221006003409.649993-4-seanjc@google.com