kernel/tools/testing/selftests/kvm/lib/memstress.c, branch linux-rolling-stable

KVM: selftests: Expand set of APIs for pinning tasks to a single CPU

2025-07-09T16:33:40Z

Expand kvm_pin_this_task_to_pcpu() into a set of APIs to allow pinning a task (or self) to a CPU (any or specific). This will allow deduplicating code throughout a variety of selftests. Opportunistically use "self" instead of "this_task" as it is both more concise and less ambiguous. Link: https://lore.kernel.org/r/20250626001225.744268-4-seanjc@google.com Signed-off-by: Sean Christopherson

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

2024-04-29T19:54:13Z

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: Provide an API for getting a random bool from an RNG

2024-04-29T19:50:42Z

Move memstress' random bool logic into common code to avoid reinventing the wheel for basic yes/no decisions. Provide an outer wrapper to handle the basic/common case of just wanting a 50/50 chance of something happening. Link: https://lore.kernel.org/r/20240314185459.2439072-3-seanjc@google.com Signed-off-by: Sean Christopherson

KVM: selftests: Provide a global pseudo-RNG instance for all tests

2024-04-29T19:50:41Z

Add a global guest_random_state instance, i.e. a pseudo-RNG, so that an RNG is available for *all* tests. This will allow randomizing behavior in core library code, e.g. x86 will utilize the pRNG to conditionally force emulation of writes from within common guest code. To allow for deterministic runs, and to be compatible with existing tests, allow tests to override the seed used to initialize the pRNG. Note, the seed *must* be overwritten before a VM is created in order for the seed to take effect, though it's perfectly fine for a test to initialize multiple VMs with different seeds. And as evidenced by memstress_guest_code(), it's also a-ok to instantiate more RNGs using the global seed (or a modified version of it). The goal of the global RNG is purely to ensure that _a_ source of random numbers is available, it doesn't have to be the _only_ RNG. Link: https://lore.kernel.org/r/20240314185459.2439072-2-seanjc@google.com Signed-off-by: Sean Christopherson

KVM: selftests: Define _GNU_SOURCE for all selftests code

2024-04-29T19:49:10Z

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

2024-01-29T16:39:14Z

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: Introduce VM "shape" to allow tests to specify the VM type

2023-11-14T13:01:07Z

Add a "vm_shape" structure to encapsulate the selftests-defined "mode", along with the KVM-defined "type" for use when creating a new VM. "mode" tracks physical and virtual address properties, as well as the preferred backing memory type, while "type" corresponds to the VM type. Taking the VM type will allow adding tests for KVM_CREATE_GUEST_MEMFD without needing an entirely separate set of helpers. At this time, guest_memfd is effectively usable only by confidential VM types in the form of guest private memory, and it's expected that x86 will double down and require unique VM types for TDX and SNP guests. Signed-off-by: Sean Christopherson Message-Id: <20231027182217.3615211-30-seanjc@google.com> Signed-off-by: Paolo Bonzini

KVM: selftests: Move dirty logging functions to memstress.(c|h)

2023-06-01T21:03:18Z

Move some helper functions from dirty_log_perf_test.c to the memstress library so that they can be used in a future commit which tests page splitting during dirty logging. Reviewed-by: Vipin Sharma Signed-off-by: Ben Gardon Link: https://lore.kernel.org/r/20230131181820.179033-2-bgardon@google.com Signed-off-by: Sean Christopherson

KVM: selftests: touch all pages of args on each memstress iteration

2023-06-01T21:03:14Z

Access the same memory addresses on each iteration of the memstress guest code. This ensures that the state of KVM's page tables is the same after every iteration, including the pages that host the guest page tables for args and vcpu_args. This difference is visible when running the proposed dirty_log_page_splitting_test[*] on AMD, or on Intel with pml=0 and eptad=0. The tests fail due to different semantics of dirty bits for page-table pages on AMD (and eptad=0) and Intel. Both AMD and Intel with eptad=0 treat page-table accesses as writes, therefore more pages are dropped before the repopulation phase when dirty logging is disabled. The "missing" page had been included in the population phase because it hosts the page tables for vcpu_args, but repopulation does not need it." Signed-off-by: Paolo Bonzini Reviewed-by: Vipin Sharma Link: https://lore.kernel.org/r/20230412200913.1570873-1-pbonzini@redhat.com [sean: add additional details in changelog] Signed-off-by: Sean Christopherson

Merge tag 'kvmarm-6.2' of https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

2022-12-09T08:12:12Z

KVM/arm64 updates for 6.2 - Enable the per-vcpu dirty-ring tracking mechanism, together with an option to keep the good old dirty log around for pages that are dirtied by something other than a vcpu. - Switch to the relaxed parallel fault handling, using RCU to delay page table reclaim and giving better performance under load. - Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping option, which multi-process VMMs such as crosvm rely on. - Merge the pKVM shadow vcpu state tracking that allows the hypervisor to have its own view of a vcpu, keeping that state private. - Add support for the PMUv3p5 architecture revision, bringing support for 64bit counters on systems that support it, and fix the no-quite-compliant CHAIN-ed counter support for the machines that actually exist out there. - Fix a handful of minor issues around 52bit VA/PA support (64kB pages only) as a prefix of the oncoming support for 4kB and 16kB pages. - Add/Enable/Fix a bunch of selftests covering memslots, breakpoints, stage-2 faults and access tracking. You name it, we got it, we probably broke it. - Pick a small set of documentation and spelling fixes, because no good merge window would be complete without those. As a side effect, this tag also drags: - The 'kvmarm-fixes-6.1-3' tag as a dependency to the dirty-ring series - A shared branch with the arm64 tree that repaints all the system registers to match the ARM ARM's naming, and resulting in interesting conflicts