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path: root/tools/testing/selftests/kvm/irq_test.c
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2026-07-31KVM: selftests: Add KVM syscall wrappers for pthread_{cancel,join}()Sean Christopherson
Add and use KVM wrappers for pthread_{cancel,join}() so that selftests don't need to manually assert that the syscalls succeeded. Note, the vast majority tests don't actually assert success, but they all obviously rely on the syscall to succeed. Other than explicitly failing if a syscall fails, no functional change intended. Link: https://patch.msgid.link/20260731195612.2697986-10-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Add KVM syscall wrapper for pthread_create()Sean Christopherson
Add and use a KVM wrapper for pthread_create() syscall so that selftests don't need to manually assert that the syscall succeeded. Note, most tests don't actually assert success, but they all obviously rely on the syscall to succeed. Other than explicitly failing if pthread_create() fails, no functional change intended. Link: https://patch.msgid.link/20260731195612.2697986-9-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-07KVM: selftests: Add xAPIC support in eventfd IRQ testDavid Matlack
Extend the eventfd IRQ test with a '-x' flag to let the user run the test in xAPIC mode instead of the default x2APIC mode. When using xAPIC mode, sanity check user input to ensure the test is being run with at most 255 vCPUs, as xAPIC can only address IDs 0-254 (255, i.e. 0xff, broadcasts to all CPUs). Signed-off-by: David Matlack <dmatlack@google.com> Co-developed-by: Josh Hilke <jrhilke@google.com> Signed-off-by: Josh Hilke <jrhilke@google.com> [sean: add sanity check on number of vCPUs] Link: https://patch.msgid.link/20260626213534.3866178-21-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-07KVM: selftests: Make number of vCPUs configurable in IRQ testDavid Matlack
Extend the eventfd IRQ test with a '-v' flag to allow the user to configure the number of vCPUs to create and run (versus only ever using a single vCPU). Update the routing logic to play nice with 32 bit IDs, enable x2APIC format in KVM (to enable 32-bit ID routing), and disable KVM's x2APIC broadcast quirk so that targeting vCPU 255 doesn't blast the interrupt to all vCPUs when in x2APIC mode. Signed-off-by: David Matlack <dmatlack@google.com> Co-developed-by: Josh Hilke <jrhilke@google.com> Signed-off-by: Josh Hilke <jrhilke@google.com> Co-developed-by: Sean Christopherson <seanjc@google.com> Link: https://patch.msgid.link/20260626213534.3866178-20-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-07KVM: selftests: Verify vCPU migration during IRQ delivery in IRQ testDavid Matlack
Extend the eventfd IRQ test with a '-m' flag to have the test migrate the target vCPU to a random physical CPU before triggering its interrupt, e.g. to validate KVM's ability to update device posted IRQ routing. Signed-off-by: David Matlack <dmatlack@google.com> Co-developed-by: Josh Hilke <jrhilke@google.com> Signed-off-by: Josh Hilke <jrhilke@google.com> [sean: pin one vCPU at a time to simplify things, use main()'s affinity] Link: https://patch.msgid.link/20260626213534.3866178-19-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-07KVM: selftests: Verify non-postable IRQ remapping in IRQ testSean Christopherson
Extend the eventfd IRQ test with an '-n' flag to route a subset of device interrupts as NMIs (Non-Maskable Interrupts) into the guest using an alternating pattern of 4 NMIs followed by 4 regular interrupts. While this adds coverage for NMI injection, the primary goal is to validate KVM's handling of non-postable interrupt delivery (AMD and Intel IOMMUs only support posting fixed IRQs targeting a single vCPU). KVM has historically bungled handling transitions between posted and remapped modes. Use NMIs to stress the transitions, because they are a reliable, architectural way to force these code paths. Signed-off-by: David Matlack <dmatlack@google.com> Co-developed-by: Josh Hilke <jrhilke@google.com> Signed-off-by: Josh Hilke <jrhilke@google.com> [sean: add GUEST_RECEIVED_INTERRUPT(), massage changelog] Link: https://patch.msgid.link/20260626213534.3866178-15-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-07KVM: selftests: Make number of IRQs configurable in IRQ testDavid Matlack
Extend the eventfd IRQ test with a '-i' flag to let the user specify the the number of IRQs to generate (instead of hardcoding the test to always generate 1000 interrupts). Signed-off-by: David Matlack <dmatlack@google.com> Co-developed-by: Josh Hilke <jrhilke@google.com> Signed-off-by: Josh Hilke <jrhilke@google.com> [sean: massage changelog] Link: https://patch.msgid.link/20260626213534.3866178-14-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-07KVM: selftests: Add option to set empty routing between IRQs in eventfd IRQ testDavid Matlack
Extend the eventfd IRQ test with an '-e' flag to set empty GSI routing between interrupts. Clobbering the GSI routing table verifies that KVM correctly handles CPUx => NULL => CPUy transitions, not just CPUx => CPUy transitions, and verifies that KVM can "rebuild" an entire routing setup. Signed-off-by: David Matlack <dmatlack@google.com> Co-developed-by: Josh Hilke <jrhilke@google.com> Signed-off-by: Josh Hilke <jrhilke@google.com> [sean: '-e' for "empty" instead of '-c' for "clear", massage changelog] Link: https://patch.msgid.link/20260626213534.3866178-13-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-07KVM: selftests: Verify interrupts are received when IRQ affinity changes in ↵David Matlack
IRQ test Extent the eventfd IRQ test with a '-a' flag to randomly affinitize the device's host IRQ to different physical CPUs throughout the test. This stresses the kernel's ability to maintain correct interrupt routing and delivery even as the underlying hardware IRQ affinity is changed dynamically via /proc/<irq>/smp_affinity{,_list}. Signed-off-by: David Matlack <dmatlack@google.com> Co-developed-by: Josh Hilke <jrhilke@google.com> Signed-off-by: Josh Hilke <jrhilke@google.com> [sean: massage changelog] Link: https://patch.msgid.link/20260626213534.3866178-12-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-07KVM: selftests: Add VFIO device support to eventfd IRQ testDavid Matlack
Extend the eventfd IRQ test with a '-d' argument that takes a BDF (in the format segment:bus:device.function) of an interrupt-capable PCI(e) device bound to VFIO, and use said device to trigger interrupts instead of always synthesizing interrupts via direct writes to the eventfd. Using a VFIO device to trigger interrupts validates the end-to-end delivery of IRQs for "real" devices, and when supported by hardware (and KVM), also validates interrupt delivery via IRQ bypass, i.e. via device posted IRQs. Now that IOMMUFD is a thing, auto-probe IOMMUFD vs. "legacy" VFIO by temporarily opening /dev/iommufd, and skip the test if neither IOMMUFD nor legacy VFIO is available. Add a '-t' option to the user override the probe logic, e.g. in case IOMMUFD is available but the system is configured for legacy usage. Note, the device must have a VFIO selftest driver in order to work with the test. A helper script to list supported devices will hopefully be available in the near future at tools/testing/selftests/vfio/scripts/list_supported_devices.sh[1]. Example: $ ./tools/testing/selftests/kvm/irq_test -d 0000:06:0a.1 Link: https://lore.kernel.org/all/20260602222941.3133236-1-jrhilke%40google.com [1] Signed-off-by: David Matlack <dmatlack@google.com> Co-developed-by: Josh Hilke <jrhilke@google.com> Signed-off-by: Josh Hilke <jrhilke@google.com> Co-developed-by: Sean Christopherson <seanjc@google.com> Link: https://patch.msgid.link/20260626213534.3866178-10-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-07KVM: selftests: Add an irqfd send+receive (and later IRQ bypass) testDavid Matlack
Add a new test, irq_test to verify that KVM correctly delivers interrupts to a running vCPU, when triggered via an eventfd bound to a KVM GSI using KVM's irqfd mechanism. This test is intentionally simple, for now. Support for sending interrupts via VFIO devices, for IRQ bypass, and for other features will be added in the near future. Add the test in common code, even though it currently will only build and run on x86, as the concept and the bulk of the host-side code isn't specific to x86. Suggested-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/kvm/20250404193923.1413163-68-seanjc@google.com Signed-off-by: David Matlack <dmatlack@google.com> Co-developed-by: Josh Hilke <jrhilke@google.com> Signed-off-by: Josh Hilke <jrhilke@google.com> [sean: use while() and TEST_ASSERT() instead of if-statement => TEST_FAIL()] Link: https://patch.msgid.link/20260626213534.3866178-8-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>