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2025-04-04selftests: kvm: revamp MONITOR/MWAIT testsPaolo Bonzini
Run each testcase in a separate VMs to cover more possibilities; move WRMSR close to MONITOR/MWAIT to test updating CPUID bits while in the VM. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-19Merge tag 'kvm-x86-selftests-6.15' of https://github.com/kvm-x86/linux into HEADPaolo Bonzini
KVM selftests changes for 6.15, part 2 - Fix a variety of flaws, bugs, and false failures/passes dirty_log_test, and improve its coverage by collecting all dirty entries on each iteration. - Fix a few minor bugs related to handling of stats FDs. - Add infrastructure to make vCPU and VM stats FDs available to tests by default (open the FDs during VM/vCPU creation). - Relax an assertion on the number of HLT exits in the xAPIC IPI test when running on a CPU that supports AMD's Idle HLT (which elides interception of HLT if a virtual IRQ is pending and unmasked). - Misc cleanups and fixes.
2025-03-19Merge tag 'kvm-x86-selftests_6.15-1' of https://github.com/kvm-x86/linux ↵Paolo Bonzini
into HEAD KVM selftests changes for 6.15, part 1 - Misc cleanups and prep work. - Annotate _no_printf() with "printf" so that pr_debug() statements are checked by the compiler for default builds (and pr_info() when QUIET). - Attempt to whack the last LLC references/misses mole in the Intel PMU counters test by adding a data load and doing CLFLUSH{OPT} on the data instead of the code being executed. The theory is that modern Intel CPUs have learned new code prefetching tricks that bypass the PMU counters. - Fix a flaw in the Intel PMU counters test where it asserts that an event is counting correctly without actually knowing what the event counts on the underlying hardware.
2025-03-19Merge tag 'kvm-x86-misc-6.15' of https://github.com/kvm-x86/linux into HEADPaolo Bonzini
KVM x86 misc changes for 6.15: - Fix a bug in PIC emulation that caused KVM to emit a spurious KVM_REQ_EVENT. - Add a helper to consolidate handling of mp_state transitions, and use it to clear pv_unhalted whenever a vCPU is made RUNNABLE. - Defer runtime CPUID updates until KVM emulates a CPUID instruction, to coalesce updates when multiple pieces of vCPU state are changing, e.g. as part of a nested transition. - Fix a variety of nested emulation bugs, and add VMX support for synthesizing nested VM-Exit on interception (instead of injecting #UD into L2). - Drop "support" for PV Async #PF with proctected guests without SEND_ALWAYS, as KVM can't get the current CPL. - Misc cleanups
2025-03-03KVM: selftests: Fix printf() format goof in SEV smoke testSean Christopherson
Print out the index of mismatching XSAVE bytes using unsigned decimal format. Some versions of clang complain about trying to print an integer as an unsigned char. x86/sev_smoke_test.c:55:51: error: format specifies type 'unsigned char' but the argument has type 'int' [-Werror,-Wformat] Fixes: 8c53183dbaa2 ("selftests: kvm: add test for transferring FPU state into VMSA") Link: https://lore.kernel.org/r/20250228233852.3855676-1-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-28KVM: selftests: Relax assertion on HLT exits if CPU supports Idle HLTSean Christopherson
If the CPU supports Idle HLT, which elides HLT VM-Exits if the vCPU has an unmasked pending IRQ or NMI, relax the xAPIC IPI test's assertion on the number of HLT exits to only require that the number of exits is less than or equal to the number of HLT instructions that were executed. I.e. don't fail the test if Idle HLT does what it's supposed to do. Note, unfortunately there's no way to determine if *KVM* supports Idle HLT, as this_cpu_has() checks raw CPU support, and kvm_cpu_has() checks what can be exposed to L1, i.e. the latter would check if KVM supports nested Idle HLT. But, since the assert is purely bonus coverage, checking for CPU support is good enough. Cc: Manali Shukla <Manali.Shukla@amd.com> Tested-by: Manali Shukla <Manali.Shukla@amd.com> Link: https://lore.kernel.org/r/20250226231809.3183093-1-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-28KVM: selftests: Assert that STI blocking isn't set after event injectionSean Christopherson
Add an L1 (guest) assert to the nested exceptions test to verify that KVM doesn't put VMRUN in an STI shadow (AMD CPUs bleed the shadow into the guest's int_state if a #VMEXIT occurs before VMRUN fully completes). Add a similar assert to the VMX side as well, because why not. Reviewed-by: Jim Mattson <jmattson@google.com> Link: https://lore.kernel.org/r/20250224165442.2338294-3-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-24KVM: selftests: Add a nested (forced) emulation intercept test for x86Sean Christopherson
Add a rudimentary test for validating KVM's handling of L1 hypervisor intercepts during instruction emulation on behalf of L2. To minimize complexity and avoid overlap with other tests, only validate KVM's handling of instructions that L1 wants to intercept, i.e. that generate a nested VM-Exit. Full testing of emulation on behalf of L2 is better achieved by running existing (forced) emulation tests in a VM, (although on VMX, getting L0 to emulate on #UD requires modifying either L1 KVM to not intercept #UD, or modifying L0 KVM to prioritize L0's exception intercepts over L1's intercepts, as is done by KVM for SVM). Since emulation should never be successful, i.e. L2 always exits to L1, dynamically generate the L2 code stream instead of adding a helper for each instruction. Doing so requires hand coding instruction opcodes, but makes it significantly easier for the test to compute the expected "next RIP" and instruction length. Link: https://lore.kernel.org/r/20250201015518.689704-12-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-14KVM: selftests: Add infrastructure for getting vCPU binary statsSean Christopherson
Now that the binary stats cache infrastructure is largely scope agnostic, add support for vCPU-scoped stats. Like VM stats, open and cache the stats FD when the vCPU is created so that it's guaranteed to be valid when vcpu_get_stats() is invoked. Account for the extra per-vCPU file descriptor in kvm_set_files_rlimit(), so that tests that create large VMs don't run afoul of resource limits. To sanity check that the infrastructure actually works, and to get a bit of bonus coverage, add an assert in x86's xapic_ipi_test to verify that the number of HLTs executed by the test matches the number of HLT exits observed by KVM. Tested-by: Manali Shukla <Manali.Shukla@amd.com> Link: https://lore.kernel.org/r/20250111005049.1247555-9-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-14KVM: selftests: Macrofy vm_get_stat() to auto-generate stat name stringSean Christopherson
Turn vm_get_stat() into a macro that generates a string for the stat name, as opposed to taking a string. This will allow hardening stat usage in the future to generate errors on unknown stats at compile time. No functional change intended. Link: https://lore.kernel.org/r/20250111005049.1247555-5-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-12KVM: selftests: Add CPUID tests for Hyper-V features that need in-kernel APICSean Christopherson
Add testcases to x86's Hyper-V CPUID test to verify that KVM advertises support for features that require an in-kernel local APIC appropriately, i.e. that KVM hides support from the vCPU-scoped ioctl if the VM doesn't have an in-kernel local APIC. Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Link: https://lore.kernel.org/r/20250118003454.2619573-5-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-12KVM: selftests: Manage CPUID array in Hyper-V CPUID test's core helperSean Christopherson
Allocate, get, and free the CPUID array in the Hyper-V CPUID test in the test's core helper, instead of copy+pasting code at each call site. In addition to deduplicating a small amount of code, restricting visibility of the array to a single invocation of the core test prevents "leaking" an array across test cases. Passing in @vcpu to the helper will also allow pivoting on VM-scoped information without needing to pass more booleans, e.g. to conditionally assert on features that require an in-kernel APIC. To avoid use-after-free bugs due to overzealous and careless developers, opportunstically add a comment to explain that the system-scoped helper caches the Hyper-V CPUID entries, i.e. that the caller is not responsible for freeing the memory. Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Link: https://lore.kernel.org/r/20250118003454.2619573-4-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-12KVM: selftests: Mark test_hv_cpuid_e2big() static in Hyper-V CPUID testSean Christopherson
Make the Hyper-V CPUID test's local helper test_hv_cpuid_e2big() static, it's not used outside of the test (and isn't intended to be). Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Link: https://lore.kernel.org/r/20250118003454.2619573-3-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-12KVM: selftests: Print out the actual Top-Down Slots count on failureSean Christopherson
Print out the expected vs. actual count of the Top-Down Slots event on failure in the Intel PMU counters test. GUEST_ASSERT() only expands constants/macros, i.e. only prints the value of the expected count, which makes it difficult to debug and triage failures. Link: https://lore.kernel.org/r/20250117234204.2600624-6-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-12KVM: selftests: Drop the "feature event" param from guest test helpersSean Christopherson
Now that validation of event count is tied to hardware support for event, and not to guest support for an event, drop the unused "event" parameter from the various helpers. No functional change intended. Link: https://lore.kernel.org/r/20250117234204.2600624-5-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-12KVM: selftests: Remove dead code in Intel PMU counters testSean Christopherson
Drop the local "nr_arch_events" in the Intel PMU counters test as the test asserts that "nr_arch_events <= NR_INTEL_ARCH_EVENTS", and then sets nr_arch_events to the max of the two. I.e. nr_arch_events is guaranteed to be NR_INTEL_ARCH_EVENTS for the meat of the test, just use NR_INTEL_ARCH_EVENTS directly. No functional change intended. Link: https://lore.kernel.org/r/20250117234204.2600624-4-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-12KVM: selftests: Only validate counts for hardware-supported arch eventsSean Christopherson
In the Intel PMU counters test, only validate the counts for architectural events that are supported in hardware. If an arch event isn't supported, the event selector may enable a completely different event, and thus the logic for the expected count is bogus. This fixes test failures on pre-Icelake systems due to the encoding for the architectural Top-Down Slots event corresponding to something else (at least on the Skylake family of CPUs). Note, validation relies on *hardware* support, not KVM support and not guest support. Architectural events are all about enumerating the event selector encoding; lack of enumeration for an architectural event doesn't mean the event itself is unsupported, i.e. the event should still count as expected even if KVM and/or guest CPUID doesn't enumerate the event as being "architectural". Note #2, it's desirable to _program_ the architectural event encoding even if hardware doesn't support the event. The count can't be validated when the event is fully enabled, but KVM should still let the guest program the event selector, and the PMC shouldn't count if the event is disabled. Fixes: 4f1bd6b16074 ("KVM: selftests: Test Intel PMU architectural events on gp counters") Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202501141009.30c629b4-lkp@intel.com Debugged-by: Dapeng Mi <dapeng1.mi@linux.intel.com> Link: https://lore.kernel.org/r/20250117234204.2600624-3-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-12KVM: selftests: Make Intel arch events globally available in PMU counters testSean Christopherson
Wrap PMU counter test's array of Intel architectrual in a helper function so that the events can be queried in multiple locations. Add a comment to explain the need for a wrapper. No functional change intended. Link: https://lore.kernel.org/r/20250117234204.2600624-2-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-01-08KVM: selftests: Add helpers for locally (un)blocking IRQs on x86Sean Christopherson
Copy KVM-Unit-Tests' x86 helpers for emitting STI and CLI, comments and all, and use them throughout x86 selftests. The safe_halt() and sti_nop() logic in particular benefits from centralized comments, as the behavior isn't obvious unless the reader is already aware of the STI shadow. Cc: Manali Shukla <Manali.Shukla@amd.com> Link: https://lore.kernel.org/r/20241220012617.3513898-1-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-01-08KVM: selftests: Use data load to trigger LLC references/misses in Intel PMUSean Christopherson
In the PMU counters test, add a data load in the measured loop and target the data with CLFLUSH{OPT} in order to (try to) guarantee the loop generates LLC misses and fills. Per the SDM, some hardware prefetchers are allowed to omit relevant PMU events, and Emerald Rapids (and possibly Sapphire Rapids) appears to have gained an instruction prefetcher that bypasses event counts. E.g. the test will consistently fail on EMR CPUs, but then pass with seemingly benign changes to the code. The event count includes speculation and cache line fills due to the first-level cache hardware prefetcher, but may exclude cache line fills due to other hardware-prefetchers. Generate a data load as a last ditch effort to preserve the (minimal) test coverage for LLC references and misses. Cc: Maxim Levitsky <mlevitsk@redhat.com> Link: https://lore.kernel.org/r/20241127235627.4049619-1-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-01-08KVM: selftests: Fix typos in x86's PMU counter test's macro variable useColton Lewis
Fix goofs in PMU counter test's assertion macros where the macros unintentionally reference variables in the parent scope. The code "works" as-is purely by accident, as all users define a variable with the correct name (and usage). Fixes: cd34fd8c758e ("KVM: selftests: Test PMC virtualization with forced emulation") Signed-off-by: Colton Lewis <coltonlewis@google.com> Reviewed-by: Mingwei Zhang <mizhang@google.com> Link: https://lore.kernel.org/r/20240918205319.3517569-2-coltonlewis@google.com [sean: massage changelog] Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-12-18KVM: selftests: Add and use a helper function for x86's LIDTIvan Orlov
Implement a function for setting the IDT descriptor from the guest code. Replace the existing lidt occurrences with calls to this function as `lidt` is used in multiple places. Signed-off-by: Ivan Orlov <iorlov@amazon.com> Link: https://lore.kernel.org/r/20241217181458.68690-7-iorlov@amazon.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-12-18KVM: selftests: Update x86's KVM PV test to match KVM's disabling exits behaviorSean Christopherson
Rework x86's KVM PV features test to align with KVM's new, fixed behavior of not allowing userspace to disable HLT-exiting after vCPUs have been created. Rework the core testcase to disable HLT-exiting before creating a vCPU, and opportunistically modify keep the paired VM+vCPU creation to verify that KVM rejects KVM_CAP_X86_DISABLE_EXITS as expected. Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com> Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com> Link: https://lore.kernel.org/r/20241128013424.4096668-18-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-12-18KVM: selftests: Fix a bad TEST_REQUIRE() in x86's KVM PV testSean Christopherson
Actually check for KVM support for disabling HLT-exiting instead of effectively checking that KVM_CAP_X86_DISABLE_EXITS is #defined to a non-zero value, and convert the TEST_REQUIRE() to a simple return so that only the sub-test is skipped if HLT-exiting is mandatory. The goof has likely gone unnoticed because all x86 CPUs support disabling HLT-exiting, only systems with the opt-in mitigate_smt_rsb KVM module param disallow HLT-exiting. Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com> Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com> Link: https://lore.kernel.org/r/20241128013424.4096668-17-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-12-18KVM: selftests: Verify KVM stuffs runtime CPUID OS bits on CR4 writesSean Christopherson
Extend x86's set sregs test to verify that KVM sets/clears OSXSAVE and OSKPKE according to CR4.XSAVE and CR4.PKE respectively. For performance reasons, KVM is responsible for emulating the architectural behavior of the OS CPUID bits tracking CR4. Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com> Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com> Link: https://lore.kernel.org/r/20241128013424.4096668-10-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-12-18KVM: selftests: Update x86's set_sregs_test to match KVM's CPUID enforcementSean Christopherson
Rework x86's set sregs test to verify that KVM enforces CPUID vs. CR4 features even if userspace hasn't explicitly set guest CPUID. KVM used to allow userspace to set any KVM-supported CR4 value prior to KVM_SET_CPUID2, and the test verified that behavior. However, the testcase was written purely to verify KVM's existing behavior, i.e. was NOT written to match the needs of real world VMMs. Opportunistically verify that KVM continues to reject unsupported features after KVM_SET_CPUID2 (using KVM_GET_SUPPORTED_CPUID). Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com> Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com> Link: https://lore.kernel.org/r/20241128013424.4096668-7-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-12-18KVM: selftests: Use canonical $(ARCH) paths for KVM selftests directoriesSean Christopherson
Use the kernel's canonical $(ARCH) paths instead of the raw target triple for KVM selftests directories. KVM selftests are quite nearly the only place in the entire kernel that using the target triple for directories, tools/testing/selftests/drivers/s390x being the lone holdout. Using the kernel's preferred nomenclature eliminates the minor, but annoying, friction of having to translate to KVM's selftests directories, e.g. for pattern matching, opening files, running selftests, etc. Opportunsitically delete file comments that reference the full path of the file, as they are obviously prone to becoming stale, and serve no known purpose. Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com> Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Acked-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/20241128005547.4077116-16-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>