wireguard-linux/tools/testing/selftests/kvm/lib/kvm_util.c, branch update-toolchain

KVM: selftests: Print the seed for the guest pRNG iff it has changed

2024-06-27T14:52:17Z

Print the guest's random seed during VM creation if and only if the seed has changed since the seed was last printed. The vast majority of tests, if not all tests at this point, set the seed during test initialization and never change the seed, i.e. printing it every time a VM is created is useless noise. Snapshot and print the seed during early selftest init to play nice with tests that use the kselftests harness, at the cost of printing an unused seed for tests that change the seed during test-specific initialization, e.g. dirty_log_perf_test. The kselftests harness runs each testcase in a separate process that is forked from the original process before creating each testcase's VM, i.e. waiting until first VM creation will result in the seed being printed by each testcase despite it never changing. And long term, the hope/goal is that setting the seed will be handled by the core framework, i.e. that the dirty_log_perf_test wart will naturally go away. Reported-by: Yi Lai Reported-by: Dapeng Mi Link: https://lore.kernel.org/r/20240627021756.144815-2-dapeng1.mi@linux.intel.com Signed-off-by: Sean Christopherson

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

2024-05-12T07:18:11Z

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.

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

2024-05-12T07:17:03Z

KVM selftests cleanups and fixes for 6.10: - Enhance the demand paging test to allow for better reporting and stressing of UFFD performance. - Convert the steal time test to generate TAP-friendly output. - Fix a flaky false positive in the xen_shinfo_test due to comparing elapsed time across two different clock domains. - Skip the MONITOR/MWAIT test if the host doesn't actually support MWAIT. - Avoid unnecessary use of "sudo" in the NX hugepage test to play nice with running in a minimal userspace environment. - Allow skipping the RSEQ test's sanity check that the vCPU was able to complete a reasonable number of KVM_RUNs, as the assert can fail on a completely valid setup. If the test is run on a large-ish system that is otherwise idle, and the test isn't affined to a low-ish number of CPUs, the vCPU task can be repeatedly migrated to CPUs that are in deep sleep states, which results in the vCPU having very little net runtime before the next migration due to high wakeup latencies.

KVM: selftests: Require KVM_CAP_USER_MEMORY2 for tests that create memslots

2024-05-02T23:12:28Z

Explicitly require KVM_CAP_USER_MEMORY2 for selftests that create memslots, i.e. skip selftests that need memslots instead of letting them fail on KVM_SET_USER_MEMORY_REGION2. While it's ok to take a dependency on new kernel features, selftests should skip gracefully instead of failing hard when run on older kernels. Reported-by: Dan Carpenter Closes: https://lore.kernel.org/all/69ae0694-8ca3-402c-b864-99b500b24f5d@moroto.mountain Suggested-by: Shuah Khan Link: https://lore.kernel.org/r/20240430162133.337541-1-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 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

selftests: kvm: switch to using KVM_X86_*_VM

2024-04-11T17:08:27Z

This removes the concept of "subtypes", instead letting the tests use proper VM types that were recently added. While the sev_init_vm() and sev_es_init_vm() are still able to operate with the legacy KVM_SEV_INIT and KVM_SEV_ES_INIT ioctls, this is limited to VMs that are created manually with vm_create_barebones(). Signed-off-by: Paolo Bonzini Message-ID: <20240404121327.3107131-16-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini

Merge tag 'kvm-x86-pmu-6.9' of https://github.com/kvm-x86/linux into HEAD

2024-03-11T14:41:09Z

KVM x86 PMU changes for 6.9: - Fix several bugs where KVM speciously prevents the guest from utilizing fixed counters and architectural event encodings based on whether or not guest CPUID reports support for the _architectural_ encoding. - Fix a variety of bugs in KVM's emulation of RDPMC, e.g. for "fast" reads, priority of VMX interception vs #GP, PMC types in architectural PMUs, etc. - Add a selftest to verify KVM correctly emulates RDMPC, counter availability, and a variety of other PMC-related behaviors that depend on guest CPUID, i.e. are difficult to validate via KVM-Unit-Tests. - Zero out PMU metadata on AMD if the virtual PMU is disabled to avoid wasting cycles, e.g. when checking if a PMC event needs to be synthesized when skipping an instruction. - Optimize triggering of emulated events, e.g. for "count instructions" events when skipping an instruction, which yields a ~10% performance improvement in VM-Exit microbenchmarks when a vPMU is exposed to the guest. - Tighten the check for "PMI in guest" to reduce false positives if an NMI arrives in the host while KVM is handling an IRQ VM-Exit.

Merge tag 'kvm-x86-selftests-6.9' of https://github.com/kvm-x86/linux into HEAD

2024-03-11T14:20:35Z

KVM selftests changes for 6.9: - Add macros to reduce the amount of boilerplate code needed to write "simple" selftests, and to utilize selftest TAP infrastructure, which is especially beneficial for KVM selftests with multiple testcases. - Add basic smoke tests for SEV and SEV-ES, along with a pile of library support for handling private/encrypted/protected memory. - Fix benign bugs where tests neglect to close() guest_memfd files.