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2026-08-24Merge tag 'kvmarm-7.3' of ↵Paolo Bonzini
https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 changes for 7.3 - Add support for 'slot' based PMU events, paired with new UAPI that compels the user to select a specific PMU implementation - Lazy save/restore of vCPU state for pKVM, along with various fixes and cleanups to the management of vCPU state between the untrusted host and pKVM hypervisor - Disable traps of EL1 registers for nested hypervisors when FEAT_NV2p1 is present, guaranteeing that EL2-specific register bits are stateful in the EL1 counterpart - Leverage FEAT_NV3 to avoid unnecessary ERET/TLBI traps when the scope of those instructions remains 'in host' (i.e. L1 kernel/userspace) - Pile of fixes for the management of the VNCR pseudo-TLB, such as under-invalidations and races with concurrent TLBIs on other vCPUs - Consolidate the non-protected and pKVM view of ICH_VTR_EL2 to a runtime-patched constant, allowing the same data to be shared with pKVM prior to dropping host privileges - Considerable pile of LLM-assisted fixes around the shop but mostly in the VGIC, our in-kernel generator of bugs (and sometimes interrupts)
2026-08-19Merge branch 'kvm-arm64/feat-nv3' into nextOliver Upton
* kvm-arm64/feat-nv3: (29 commits) : Support for FEAT_NV2p1 and FEAT_NV3, courtesy of Marc Zyngier : : Couple of accelerations for nested virtualization: : : - Elide traps for EL1 alias registers when hardware guarantees that : EL2-only bits are stateful (NV2p1) : : - Use TGE-aware hardware to avoid unnecesary ERET/TLBI traps that : remain 'in-context' (i.e. L1 kernel/userspace) arm64: Add override for ID_AA64MMFR4_EL1.NV_frac KVM: arm64: selftest: Add NVHCR_EL2 to get-reg-list KVM: arm64: Expose FEAT_NV3 to guests KVM: arm64: Add FEAT_NV3 detection KVM: arm64: Engage NV3 TLBI trap elision KVM: arm64: Engage NV3 ERET trap elision KVM: arm64: Add NVHCR_EL2 context switching KVM: arm64: Add routing for NVHCR_EL2 trap KVM: arm64: Add NVHCR_EL2 handling to the sysreg array KVM: arm64: Add sanitisation for NVHCR_EL2 KVM: arm64: Make HCR_EL2 a non-VNCR register KVM: arm64: Add kvm_has_nv{2,3}() predicates KVM: arm64: Add NV3 control bits to HCRX_EL2 sanitisation KVM: arm64: Split NV-specific exit fixups from the non-NV handling arm64: Add ARM64_HAS_NV3 capability arm64: sysreg: Add HCRX_EL2 bits related to FEAT_NV3 arm64: sysreg: Add NVHCR_EL2 description as a mirror of HCR_EL2 arm64: Add FEAT_NV2p1 detection KVM: arm64: Expose FEAT_NV2p1 to NV guests KVM: arm64: Relax CNTHCTL_EL2 handling when FEAT_NV2p1 is present ... Signed-off-by: Oliver Upton <oupton@kernel.org>
2026-08-19Merge branch 'kvm-arm64/pkvm-7.3' into nextOliver Upton
* kvm-arm64/pkvm-7.3: (26 commits) : pKVM updates for 7.3 : : - Avoid name collision on trace_clock() when CONFIG_NVHE_EL2_TRACING is : disabled (Mostafa Saleh) : : - Clean up state tracking for whether the EL2 shadow VM has been : created (Fuad Tabba) : : - Synchronize SCTLR_EL1 when injecting an exception to use current : PAN/SSBS state (Fuad Tabba) : : - Avoid unnecessary cache maintenance when I/D-cache are known to be : coherent in pKVM (Mostafa Saleh) : : - Lazy vCPU context save/restore for pKVM (Fuad Tabba) : : - Various fixes to the stage-2 MMU for pKVM (Fuad Tabba) : : - Allow counter offsetting of non-protected guests in protected mode : (Mostafa Saleh) : : - Condition the 'broken CNTVOFF' mitigation on a VM actually having a : nonzero offset, fixing boot failures of pVMs on affected hardware : (Mostafa Saleh) KVM: arm64: Fix hvhe and broken CNTVOFF_EL2 KVM: arm64: Fix timer offsets for non-protected VMs KVM: arm64: Make timer_get_offset() work in all contexts KVM: arm64: selftests: Add stage-2 block transition test KVM: arm64: Don't advertise eager page splitting under pKVM KVM: arm64: Don't WARN on pKVM stage-2 map failures KVM: arm64: Skip pKVM stage-2 flush when FWB is enabled KVM: arm64: Top up stage-2 memcache for dirty logging faults KVM: arm64: Top up the memcache for pKVM permission faults KVM: arm64: Skip cache maintenance for non-cacheable pKVM mappings KVM: arm64: Implement lazy vCPU state sync for non-protected guests KVM: arm64: Add primitives to flush/sync the VGIC state at EL2 KVM: arm64: Minimise EL2's exposure of host VGIC state during world switch KVM: arm64: Add host and hypervisor vCPU lookup primitives KVM: arm64: Move PSCI helper functions to a shared header KVM: arm64: Factor out reusable vCPU reset helpers KVM: arm64: Make vcpu_{read,write}_sys_reg available to HYP code KVM: arm64: Extract MPIDR computation into a shared header KVM: arm64: selftests: Add a userspace watchpoint test KVM: arm64: Flush external_mdscr_el1 to the pKVM hyp vCPU ... Signed-off-by: Oliver Upton <oupton@kernel.org>
2026-08-19Merge branch 'kvm-arm64/pmu-7.3' into nextOliver Upton
* kvm-arm64/pmu-7.3: : vPMU updates for 7.3 : : - Support for slot-based PMU events, relying on new UAPI that makes : selection of a vPMU implementation mandatory (Congkai Tan) KVM: arm64: Add KVM_ARM_VCPU_PMU_V3_STRICT vCPU feature KVM: arm64: Ignore writes to PMCR_EL0.N when using strict UAPI KVM: arm64: Advertise STALL_SLOT* in PMCEID1 under strict PMUv3 UAPI KVM: arm64: Expose PMMIR_EL1.SLOTS under strict PMUv3 UAPI Signed-off-by: Oliver Upton <oupton@kernel.org>
2026-08-18Merge tag 'kvm-x86-misc-7.3' of https://github.com/kvm-x86/linux into HEADPaolo Bonzini
KVM x86 misc changes for 7.3 - Fix VPID virtualization bugs where KVM would fail to flush hardware TLBs. - Harden the SNP and TDX "populate" ioctls against bad input, and to prepare for supporting in-place private<=>shared conversion. - Fix a variety of #DB priority bugs. - Fix a class of races related to enabling Hyper-V emulation on a vCPU after the vCPU is visible to the rest of KVM. - Use static calls for nested virtualization ops. - Move more KVM-internal code out of x86's kvm_host.h. - Enumerate support for a variety of Zhaoxin instructions that don't require explicit virtualization. - Fix missing EFER validation bugs, including in the KVM_SET_SREGS* path. - Harden kvm_vcpu_map() against double-mapping and thus leaking references. - Misc fixes and cleanups, e.g. for largely benign syzkaller splats.
2026-08-18Merge tag 'kvm-x86-selftests2-7.3' of https://github.com/kvm-x86/linux into HEADPaolo Bonzini
KVM selftests changes for 7.3, part 2 - Fix several issues with seeding KVM's pRNG, and rework the pRNG APIs to that the pRNG can be sanely used in host code, not just guest code. - Add an IRQ test to validate virtual IRQ deliverty for IRQs wired up via KVM_IRQFD + KVM_SET_GSI_ROUTING, with optional support for triggering IRQs via writes to an assigned VFIO device. - Add syscall wrappers to assert success on a variety of pthreads and CPU affinity APIs. - Set vCPU pthread affinity as early as possible to reduce contention issues that were surfaced by PREEMPT_LAZY, which result in runtimes of over a minute on large hosts, versus the expected ~5 seconds. - Rework the PMU counters test to run each testcase using a single VM with many vCPUs for each sub-testcase, instead of using a unique VM for each sub-testcase. This cuts the runtime by ~20x.
2026-08-18Merge tag 'kvm-x86-selftests-7.3' of https://github.com/kvm-x86/linux into HEADPaolo Bonzini
KVM selftests changes for 7.3, part 1 - Clean up nested SVM's handling of GPRs on L2<=>L1 transitions, reuse the functionality for nested VMX, and drop the ucall hack that was fudging around the lack of GPR switching on nVMX. - Add a stress test to verify KVM doesn't clobber/drop #PF state, e.g. CR2, across save/restore, including when L2 is active. - Add a test to verify KVM_CREATE_VM accepts exactly what is reported by KVM_CAP_VM_TYPES. - Misc selftests fixes and cleanups
2026-08-18Merge tag 'loongarch-kvm-7.3' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson into HEAD LoongArch KVM changes for v7.3 1. Advertise already-supported capabilities. 2. Some bug fixes about timer and MMIO. 3. Some hardening about interrupt injection. 4. Replace kvm_err() with kvm_pr_unimpl(). 5. Add FPU/LSX/LASX test cases for selftests.
2026-08-18Merge tag 'kvm-riscv-7.3-1' of https://github.com/kvm-riscv/linux into HEADPaolo Bonzini
KVM/riscv changes for 7.3 - Svadu/Zicfiss/Zicfilp FWFT support for Guest - Use try_cmpxchg for IMSIC MRIF RMW - More arch-specific tracepoints in KVM RISC-V - Eager Page Splitting for KVM RISC-V - Optimize hfence request handling for SMP Guests - Improve dirty log clearing by skipping zero bits in mask - Guard HFENCE range loops against overflow - CPU PM notifiers in KVM RISC-V for non-retentive idle states - Fix kernel-mode vector context save/restore for Guest
2026-08-10KVM: selftests: Create one VM with many vCPUs for each major PMU counters testSean Christopherson
To reduce the runtime of the PMU counters test by an order of magnitude, create one VM per category of test (arch events, GP PMCs, fixed PMCs), with N vCPUs per VM, where 'N' is the number of testscases to run per category. The vast majority of the test's runtime is spent creating VMs, because while creating a VM only takes a few milliseconds, the total time adds up when creating hundreds of VMs. The only reason the test creates so many VMs is because KVM disallows changing the virtual PMU model after a vCPU runs, so rather than create an entirely new VM just to get a "fresh" vCPUs, simply use a different vCPU. On an Emerald Rapids host, this reduces the runtime from 75+ seconds to less than 6 seconds. Opportunistically fix a typo in the comment about unavailable_masks pointed out by Like Xu[1]. Link: https://lore.kernel.org/all/20260625090155.6326-1-likexu@tencent.com[1] Link: https://patch.msgid.link/20260804210046.3413149-3-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-08-10KVM: LoongArch: selftests: Add FPU/LSX/LASX test casesBibo Mao
Add FPU/LSX/LASX test cases and verify FPU register get and set APIs, the FPU width supports 64/128/256 bits. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2026-08-10KVM: LoongArch: selftests: Enable LSX/LASX by auto detectionBibo Mao
Add LSX and LASX features when VM is created. These features are detected firstly, enable it if it is available on host machine. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2026-08-05KVM: x86/pmu: Clean up vPMU comments and stray blank linesLike Xu
Tidy up the x86 vPMU emulation code and its selftests by fixing comments that no longer reflect the code along with assorted spelling and grammar mistakes, and by dropping redundant blank lines reported by checkpatch. No functional change intended. Signed-off-by: Like Xu <likexu@tencent.com> Link: https://patch.msgid.link/20260625090155.6326-1-likexu@tencent.com [sean: keep quotes around "hit", shove sequences fix into separate patch] Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-08-05KVM: selftests: Test one random GP counter in PMU arch events testcaseSean Christopherson
To significantly reduce the PMU counter test's runtime, without sacrificing test coverage in the aggregate, test a random GP counter in the arch events testcase instead of testing every possible GP counter. Testing every PMC in every run of the test significantly increases the runtime of the test, without providing an equivalent increase in validation coverage, as the odds of a KVM having a bug that only affected a subset of counters and only when testing all other counters are extremely low. Opportunistically clean up kvm_random_u64_in_range() to eliminate unnecessary newlines. Link: https://patch.msgid.link/20260804210046.3413149-2-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Add a test for KVM_CREATE_VM VM type enforcementHemanth Selam
KVM_CAP_VM_TYPES advertises the bitmap of VM types that KVM_CREATE_VM accepts, but nothing verified that the ioctl actually enforces it: that every advertised type can be created and every non-advertised type is rejected. sev_init2_tests carried a TODO for this ("check that unsupported types cannot be created. Probably a separate selftest"), but the check is not specific to SEV or KVM_SEV_INIT2, and not even to x86. Add a standalone test that walks the type space and, for each value, asserts that KVM_CREATE_VM succeeds iff the corresponding bit is set in KVM_CAP_VM_TYPES, and otherwise fails with -EINVAL. The walk extends past bit 31 so that out-of-range type values, which can never be advertised in the u32 bitmap, are also confirmed to be rejected. The test only depends on KVM_CAP_VM_TYPES, so it lives in the common set and is skipped on architectures that don't advertise the capability. Drop the now-addressed TODO from sev_init2_tests.c. Tested on an AMD SEV-SNP capable host. With KVM_CAP_VM_TYPES=0x15 (DEFAULT/SEV/SNP), only the advertised types are created and everything else is rejected: $ strace -e trace=ioctl ./vm_types_test 2>&1 | grep KVM_CREATE_VM ioctl(3, KVM_CREATE_VM, 0) = 4 # DEFAULT ioctl(3, KVM_CREATE_VM, 0x1) = -1 EINVAL # SW_PROTECTED ioctl(3, KVM_CREATE_VM, 0x2) = 4 # SEV ioctl(3, KVM_CREATE_VM, 0x3) = -1 EINVAL # SEV-ES ioctl(3, KVM_CREATE_VM, 0x4) = 4 # SNP ioctl(3, KVM_CREATE_VM, 0x5) = -1 EINVAL # TDX ... 0x6..0x3f all -1 EINVAL ... Reloading kvm_amd with sev_snp=0 drops the bitmap to 0x5 and only types 0 and 2 are then created, confirming the test tracks the advertised set rather than hard-coded types. Signed-off-by: Hemanth Selam <hemanth.selam@gmail.com> Link: https://patch.msgid.link/20260710050442.826777-1-hemanth.selam@gmail.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Extend the invalid nVMX guest state test to cover RSMHao Zhang
Extend the invalid nVMX guest state to cover RSM, i.e. to validate that KVM synthesizes SHUTDOWN for L1 if SMRAM is clobbered with invalid guest state during an L2 => SMI => RSM => L2 sequence. Note, unlike the existing testcase, clobbering SMRAM should result in L1, not L2, getting SHUTDOWN / TRIPLE_FAULT, as RSM is architecturally defined to trigger shutdown if the CPU detects invalid state. Signed-off-by: Hao Zhang <hao_zhang_kdev@163.com> Co-developed-by: Sean Christopherson <seanjc@google.com> Link: https://patch.msgid.link/20260731173340.2644656-7-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Refactor invalid nVMX state test to prepare for RSM testcaseSean Christopherson
In the invalid nVMX guest state test, extract the creation of the VM and initial running of the vCPU to get to L2 into helpers so that the common code can be reused to extend the test to also cover RSM. Eliminate the unnecessary global "vm", and opportunistically free the VM after the testcase as there's zero reason not to. Opportunistically assert that L2 is never resumed after the I/O exit to L1, e.g. to guard against false passes. Link: https://patch.msgid.link/20260731173340.2644656-6-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Use port 0x80 in invalid nVMX guest state testSean Christopherson
Use port 0x80 instead of 0x2000 to trigger an L2 => L0 VM-Exit in the nVMX invalid guest state test, so that the test can be expanded to cover RSM in the L2 => SMI => L2 path without having to manually encode a MOV to DX (the immediate form of IN only supports an imm8). Use port 0x80 as it's a well-known port and is used by other tests, e.g. in the coalesced I/O test. Link: https://patch.msgid.link/20260731173340.2644656-5-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Add KVM syscall wrappers for pthread_{g,s}etaffinity_np()Sean Christopherson
Add and use KVM wrappers for pthread_{g,s}etaffinity_np() so that selftests don't need to manually assert that the syscalls succeeded, and so that they don't need to manually pass in sizeof(cpu_set_t) for the size. Link: https://patch.msgid.link/20260731195612.2697986-12-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Clean up global constants in hardware disable testSean Christopherson
Rename the global constants in the hardware disable test to better capture what they control, and open code the literal number of sleeping tasks and iterations instead of using power-of-2 math to express values that are 100% arbitrary. Opportunistically tag the global semaphore with "static". No functional change intended. Link: https://patch.msgid.link/20260731195612.2697986-13-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Add helper APIs to cancel+join pthreadsSean Christopherson
Deduplicate test code that does cancel()+join() on pthreads by adding a collection of syscall wrappers. The tests that asynchronously cancel pthreads, i.e. use PTHREAD_CANCEL_ASYNCHRONOUS, are particularly ugly, especially since it's not immediately obvious why those tests assert on the thread being CANCELED, whereas others do not. No functional change intended. Link: https://patch.msgid.link/20260731195612.2697986-11-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
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>
2026-07-31KVM: selftests: Drop unreachable, dead code from hardware disable testSean Christopherson
Drop all of the code that is unreachable in the hardware disable test, as it adds a lot of noise that makes the test seem far more complicated than it actually is. Link: https://patch.msgid.link/20260731195612.2697986-8-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Affine threads to random CPUs in hardware disable testSean Christopherson
Affine the worker threads to random CPUs in the hardware disable test, and honor the starting CPU set in the process. Hardcoding to CPUs 0-3 is both wrong and less interesting than running on random CPUs. Opportunistically convert the local 'i' to an int, as the macros it tests against are signed, and using 'i' as an iterator is conventionally declared as an int. Link: https://patch.msgid.link/20260731195612.2697986-7-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Extract picking of random CPU from cpu_set_t to separate APISean Christopherson
Extract kvm_pick_random_cpu() out of pin_task_to_random_cpu() so that tests can choose a random CPU without having to immediately pin a task to that CPU. No functional change intended. Link: https://patch.msgid.link/20260731195612.2697986-6-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Return the target CPU from pin_task_to_random_cpu()Sean Christopherson
When pinning a task to a random CPU, return which CPU the task was pinned to so that the caller can do things like avoid running other tasks on the target CPU. Link: https://patch.msgid.link/20260731195612.2697986-5-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Pre-set threads affinity in hardware disable test when possibleSean Christopherson
When building against a libc that provides pthread_attr_setaffinity_np(), pre-set the grandchildren threads CPU affinity in the hardware disable test to further reduce the perceived latency of pthread_create(). On large NUMA systems, this reduces the average runtime from ~10s to ~5s. Link: https://patch.msgid.link/20260731195612.2697986-4-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Set threads CPU affinity before doing work in hardware ↵Sean Christopherson
disable test Affine worker threads to their target pCPU set *before* doing any work in the hardware disable test. When running a preemptible kernel on a NUMA system with a large number of CPUs (100+ of CPUs), waiting to set the affinity of the grandchildren until after the grandchild is fully spun up results in total test runtimes of over a minute, presumably due to cross-node NUMA penalties and scheduler lock contention. E.g. from the perspective of the caller, when waiting to affine the tasks, pthread_create() takes ~100x longer. Link: https://patch.msgid.link/20260731195612.2697986-3-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Add a KVM syscall wrapper for sched_setaffinity()Sean Christopherson
Add and use a KVM wrapper for sched_setaffinity() so that selftests don't need to manually assert that the syscall succeeded. No functional change intended. Link: https://patch.msgid.link/20260731195612.2697986-2-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: selftests: Only link to VFIO library on x86Sean Christopherson
Link to the VFIO library only on architectures where it's actually needed, i.e. only on architectures that support irq_test, which is currently x86-only. The irq_test series, which pulled in VFIO support, effectively raced with commit e65f1bf8a2db ("vfio: selftests: Extend container/iommufd setup for passing vf_token"). I.e. when the KVM test was posted, pulling in libvfio.mk didn't require linking to any new libraries other than VFIO itself. Now that libvfio.mk pulls in luuid, unconditionally linking in support for VFIO is quite onerous, especially when cross-compiling, as it requires installing what is effectively an unused library on four architectures. Eventually KVM selftests will likely support irq_test and thus need to link to VFIO on architectures other than x86, but at least then there will be some amount of gain for the pain. Fixes: a262fc49e0aa ("KVM: selftests: Build and link selftests/vfio/lib into KVM selftests") Cc: David Matlack <dmatlack@google.com> Cc: Josh Hilke <jrhilke@google.com> Link: https://patch.msgid.link/20260730165159.1988017-1-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-31KVM: arm64: selftest: Add NVHCR_EL2 to get-reg-listMarc Zyngier
Since we now expose a new system register on NV3-capable HW when the guest is exposed to it, add it to the existing checker. FWIW. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://patch.msgid.link/20260730071022.296811-29-maz@kernel.org Signed-off-by: Oliver Upton <oupton@kernel.org>
2026-07-31KVM: arm64: selftests: Add stage-2 block transition testFuad Tabba
Add a test for the two stage-2 granularity changes dirty logging forces at fault time, asserting the guest completes with no KVM_RUN error. The first scenario collapses a page into a hugetlb-backed block: it writes under logging, re-write-protects the page via GET_DIRTY_LOG, then writes again with logging off. The second splits blocks: it faults in several non-executable 2M blocks, enables logging, then executes in each block so an execute permission fault splits it. It is skipped when CTR_EL0.DIC is set, since mappings are then executable and no execute fault occurs. Both paths make the fault handler allocate under mmu_lock, so a backend that fails to stage that memory returns a KVM_RUN error or crashes the host. The property holds on any host. On a pKVM host, where a non-protected guest uses the pkvm_pgtable_*() backend, it also guards that backend's fault-time staging. Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev> Tested-by: Bradley Morgan <include@grrlz.net> # On QEMU arm64 host Test: Bradley Morgan <include@grrlz.net> # On QEMU arm64 host Link: https://patch.msgid.link/20260717130317.1953574-8-fuad.tabba@linux.dev Signed-off-by: Oliver Upton <oupton@kernel.org>
2026-07-30KVM: arm64: selftests: Add a userspace watchpoint testFuad Tabba
debug-exceptions covers guest self-hosted debug and userspace single-step, but not a userspace (KVM_GUESTDBG_USE_HW) watchpoint, whose KVM_EXIT_DEBUG reports the accessed address in debug.arch.far. Add a test that installs a host-directed write watchpoint and checks that the reported address matches the accessed variable. Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev> Link: https://patch.msgid.link/20260726143643.303456-3-fuad.tabba@linux.dev Signed-off-by: Oliver Upton <oupton@kernel.org>
2026-07-30KVM: arm64: Expose PMMIR_EL1.SLOTS under strict PMUv3 UAPICongkai Tan
Introduce a new field pmmir_slots in struct kvm_arch to store PMMIR_EL1.SLOTS. It only saves the actual hardware PMU value when the VMM explicitly selects a PMU under KVM_ARM_VCPU_PMU_V3_STRICT. Otherwise, it stays 0 after allocation. Use this field to implement guest access, userspace get, and userspace set for PMMIR_EL1: - access_pmmir(): uses the value in kvm->arch.pmmir_slots directly. If the VMM selected a PMU and KVM_ARM_VCPU_PMU_V3_STRICT is set, the guest can correctly read the underlying core's SLOTS. Otherwise, it continues to read 0 since the true SLOTS value can be nondeterministic. - get_pmmir(): same as access_pmmir(). - set_pmmir(): only the SLOTS field is writable; a value setting any other bit is rejected with -EINVAL, since get_pmmir() returns SLOTS zero-extended. A value of 0 resets kvm->arch.pmmir_slots to 0 for backward compatibility, as the register is RAZ in older KVM, a value matching the current SLOTS is accepted as a no-op, and anything else is rejected with -EINVAL. Once the VM has run PMMIR_EL1 is immutable, so a mismatching write then returns -EBUSY. The register is now exposed via KVM_GET_REG_LIST for PMUv3 vCPUs, so add it to the get-reg-list selftest's PMU register list. Signed-off-by: Congkai Tan <congkai@amazon.com> Reviewed-by: Geoff Blake <blakgeof@amazon.com> Reviewed-by: Haris Okanovic <harisokn@amazon.com> Reviewed-by: Stanislav Spassov <stanspas@amazon.de> Co-developed-by: Oliver Upton <oupton@kernel.org> Reviewed-by: Fuad Tabba <fuad.tabba@linux.dev> Tested-by: Fuad Tabba <fuad.tabba@linux.dev> Link: https://patch.msgid.link/20260722202702.4165917-2-congkai@amazon.com Signed-off-by: Oliver Upton <oupton@kernel.org>
2026-07-29KVM: riscv: selftests: add Zicfiss/Zicfilp extension to get-reg-list testInochi Amaoto
The KVM RISC-V allows Zicfiss/Zicfilp extensions for Guest/VM so add these extensions to get-reg-list test. Assisted-by: YuanSheng:claude-4.7-opus Co-developed-by: Quan Zhou <zhouquan@iscas.ac.cn> Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn> Signed-off-by: Inochi Amaoto <inochiama@gmail.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20260713010302.303278-9-inochiama@gmail.com Signed-off-by: Anup Patel <anup@brainfault.org>
2026-07-29KVM: selftests: Trigger L2->L1 exits stress save+restore and #PF testYosry Ahmed
Extend the testing coverage in L2 by forcing a nested VM-Exit from L2 to L1 right after restore on every other iteration. Forcing a nested VM-Exit while L0 has control (e.g. without explicitly running L2 and making a hypercall) is valuable, as it often happens during live migration (e.g. L1 timer interrupt fires by the time the VM lands on the destination). To force the nested VM-Exit inject a #UD in to the saved vCPU state, and intercept #UD from L1. With this change, the test reliably reproduces the CR2 bug fixed by commit 5c247d08bc81 ("KVM: nSVM: Use vcpu->arch.cr2 when updating vmcb12 on nested #VMEXIT") -- at least on Milan, Genoa, and Turin CPUs. Assisted-by: Gemini:gemini-3.1-pro Signed-off-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260728174232.2423257-14-yosry@kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-29KVM: selftests: Support running stress save+restore and #PF test in L2Yosry Ahmed
Extend the stress test to allow running the access+#PF code in L2 instead of L1 by adding proper L1 guest code to bootstrap L2. By default, the test runs in L2 after running in L1 if nested is supported. Assisted-by: Gemini:gemini-3.1-pro Signed-off-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260728174232.2423257-13-yosry@kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-29KVM: selftests: Trigger save+restore randomly in the #PF stress testYosry Ahmed
Instead of an explicit GUEST_SYNC() after each access+#PF, run another thread that keeps sending SIGUSR to the vCPU thread, essentially triggering exits to userspace and save+restore on random points in guest execution. This makes the test a lot more meaningful as it opens the door to exercising race conditions between #PF handling in the guest and save+restore in the host. The signals are ignored using SIG_IGN outside of __vcpu_run() to avoid interrupting other ioctls/sysctls performed by the test. Assisted-by: Gemini:gemini-3.1-pro Signed-off-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260728174232.2423257-12-yosry@kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-29KVM: selftests: Add basic stress test for save+restore and #PF handlingYosry Ahmed
Add a basic stress test for handling #PFs in a guest while the host is doing save+restore cycles. The guest periodically accesses non-present memory causing a #PF, and the #PF handler walks the page tables and updates the PTE to be present, like a proper #PF handler. After every access (and #PF), the guest triggers a sync and the test performs save+restore of the VM. This is not very meaningful as save+restore are performed after the access and #PF handling complete, but following changes will change that. Assisted-by: Gemini:gemini-3.1-pro Signed-off-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260728174232.2423257-11-yosry@kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-29KVM: selftests: Do not intercept #PF by default in nVMX testsYosry Ahmed
init_vmcs_control_fields() sets PFEC_MASK and PFEC_MATCH so that they never match, which reverses the meaning of the PF_VECTOR bit in EXCEPTION_BITMAP (which is zeroed), effectively enabling #PF interception by default. The relevant part of the SDM describes this: When a page fault occurs, a processor consults (1) bit 14 of the exception bitmap; (2) the error code produced with the page fault [PFEC]; (3) the page-fault error-code mask field [PFEC_MASK]; and (4) the page-fault error-code match field [PFEC_MATCH]. It checks if PFEC & PFEC_MASK = PFEC_MATCH. If there is equality, the specification of bit 14 in the exception bitmap is followed (for example, a VM exit occurs if that bit is set). If there is inequality, the meaning of that bit is reversed (for example, a VM exit occurs if that bit is clear). Clear PFEC_MATCH such that there is equality, and the #PF bit in the exception bitmap is followed, so that #PFs are not intercepted by default, same as every other exception. This also allows tests to set the #PF bit in the exception bitmap if they want to intercept #PFs, without having to muck with the PFEC_{MASK,MATCH} fields. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260728174232.2423257-10-yosry@kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-29KVM: selftests: Expose PTE masks to guests as part of an MMUYosry Ahmed
Expose a guest_mmu to the guest to allow guest code to use the PTE masks for page table manipulation. Since guest page tables are not mapped in the guest by default, zero the PGD in guest_mmu in an attempt to make it more difficult for new tests to shoot themselves in the foot and assume that page tables can be immediately used by guest code. Ultimately, guest code can read CR3 any way, so guest_mmu.pgd doesn't add a lot of value. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260728174232.2423257-9-yosry@kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-29KVM: selftests: Add a blank line before logging assertion failuresYosry Ahmed
Add a blank line for visual separation, which is especially useful for tests that use carriage returns for same-line printing, in case a failure occurs before a blank line is ever logged by the test. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260728174232.2423257-8-yosry@kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-29KVM: selftests: Drop HORRIFIC_L2_UCALL_CLOBBER_HACKYosry Ahmed
Now that nVMX test codes preserves GPRs across nested VM-Exits (specifically RBP, RDX, and RDI among others), drop the ucall-specific hack to avoid clobbering these registers. Assisted-by: Gemini:gemini-3.1-pro Signed-off-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260728174232.2423257-7-yosry@kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-29KVM: selftests: Reuse GPR switching logic for nVMXYosry Ahmed
Reuse the GPR switching logic for nVMX by defining VMX_SWITCH_GPRS_ASM, which is essentially the same as SVM_SWITCH_GPRS_ASM but also switches RAX and doesn't switch RFLAGS, replacing the push/pop of a subset of the registers. The long clobber list of registers is no longer needed as registers are saved and restored appropriately (and not clobbered by L2). Define VMX_SWITCH_GPRS_ASM before including evmcs.h, such that it can be used by evmcs_vmlaunch() and evmcs_vmresume(). This replaces the apparently thread-safe push/pop sequence with the global GPR switching logic used by SVM, which isn't thread-safe at all. However this is still an improvement because: - The VMX logic is half-baked and prompts the UCALL clobber hack as it doesn't properly save/restore everything. Reusing the GPR switching logic used by SVM allows for dropping that hack. - Hitting a problem due to half-baked GPR save/restore logic is arguably more likely than thread-safety. Evidently, adding more involved stress tests fails on VMX with the existing push/pop sequence. OTOH, there are no known failures on SVM due to lack of thread-safety fo save/restore. Only one test currently uses more than one vCPU with nested (the memstress test). The logical next step is to move the guest_regs to be per-vCPU, making it thread-safe for both VMX and SVM in a proper way. Assisted-by: Gemini:gemini-3.1-pro Signed-off-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260728174232.2423257-6-yosry@kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-29KVM: selftests: Handle rflags save/restore for SVM in guest_regsYosry Ahmed
Instead of handling rflags separately, add it to guest_regs. No functional change intended. Assisted-by: Gemini:Gemini-Next Signed-off-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260728174232.2423257-5-yosry@kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-29KVM: selftests: Rework GPR registers switching for SVM (and fix offsets)Yosry Ahmed
The assembly code defined by SAVE_GPR_C uses the wrong offsets for some registers in guest_regs. For example, the offset of RCX should be 0x08 not 0x10. Also, the last offset in the struct (R15) is 0x78, not 0x80, so the code actually saves and restore beyond the end of gpr64_regs. Eliminate hardcoded offsets by dynamically generating offsets using offset_of() and using macros to pass the offsets to assembly as asm constraints. To avoid register conflicts in inline assembly (since almost all GPRs are context-switched), access guest_regs via absolute symbol addressing (guest_regs + offset) rather than using a base register which could get overwritten mid-assembly. While at it, rename SAVE_GPR_C and LOAD_GPR_C to a single macro, SVM_SWITCH_GPRS_ASM, rename gpr64_regs to guest_regs, and expose it in processor.h (in preparation for reusing it for VMX). Assisted-by: Gemini:Gemini-Next Signed-off-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260728174232.2423257-4-yosry@kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-29KVM: selftests: Fix RAX and RFLAGS VMCB offsets when running L2Yosry Ahmed
The offsets used (0x170 and 0x1f8) are offsets within vmcb_save_area, not vmcb. The correct offsets should include the base of vmcb_save_area within vmcb (which is 0x400 -- so 0x570 and 0x5f8). Instead of just correcting the offsets, use vmcb->save.rax and vmcb->save.rflags as parameters to the asm block and avoid hardcoding offsets completely. While at it, also use guest_regs.rax directly instead of assuming it's at offset 0 of guest_regs. Note: "+m" must be used for vmcb_rax and vmcb_rflags, as caching those fields in registers would be wrong as the underlying KVM will update them in memory. The same problem was recently fixed (differently) for kvm-unit-tests [1]. [1]https://lore.kernel.org/all/20260521092311.86030-1-pbonzini@redhat.com/ Reported-by: Sashiko <sashiko-bot@kernel.org> Closes: https://sashiko.dev/#/patchset/20260518202514.2037078-1-yosry%40kernel.org?part=1 Signed-off-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260728174232.2423257-3-yosry@kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-29KVM: selftests: Use __stringify() instead of custom XSTR() macrosYosry Ahmed
Drop the custom defined XSTR() macros in KVM selftests and use __stringify() instead. Include stringify.h in test_util.h to make it available for all tests instead of including it in all the tests that need it, as more tests will start using it. No functional change intended. Signed-off-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260728174232.2423257-2-yosry@kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
2026-07-29KVM: riscv: selftests: add Svadu FWFT extension to get-reg-list testInochi Amaoto
The KVM RISC-V allows Svadu FWFT for Guest/VM so add this extension to get-reg-list test. Assisted-by: YuanSheng:claude-4.7-opus Co-developed-by: Quan Zhou <zhouquan@iscas.ac.cn> Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn> Signed-off-by: Inochi Amaoto <inochiama@gmail.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20260713010302.303278-3-inochiama@gmail.com Signed-off-by: Anup Patel <anup@brainfault.org>