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* KVM: Fix vcpu_array[0] racesMichal Luczaj2023-05-191-6/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In kvm_vm_ioctl_create_vcpu(), add vcpu to vcpu_array iff it's safe to access vcpu via kvm_get_vcpu() and kvm_for_each_vcpu(), i.e. when there's no failure path requiring vcpu removal and destruction. Such order is important because vcpu_array accessors may end up referencing vcpu at vcpu_array[0] even before online_vcpus is set to 1. When online_vcpus=0, any call to kvm_get_vcpu() goes through array_index_nospec() and ends with an attempt to xa_load(vcpu_array, 0): int num_vcpus = atomic_read(&kvm->online_vcpus); i = array_index_nospec(i, num_vcpus); return xa_load(&kvm->vcpu_array, i); Similarly, when online_vcpus=0, a kvm_for_each_vcpu() does not iterate over an "empty" range, but actually [0, ULONG_MAX]: xa_for_each_range(&kvm->vcpu_array, idx, vcpup, 0, \ (atomic_read(&kvm->online_vcpus) - 1)) In both cases, such online_vcpus=0 edge case, even if leading to unnecessary calls to XArray API, should not be an issue; requesting unpopulated indexes/ranges is handled by xa_load() and xa_for_each_range(). However, this means that when the first vCPU is created and inserted in vcpu_array *and* before online_vcpus is incremented, code calling kvm_get_vcpu()/kvm_for_each_vcpu() already has access to that first vCPU. This should not pose a problem assuming that once a vcpu is stored in vcpu_array, it will remain there, but that's not the case: kvm_vm_ioctl_create_vcpu() first inserts to vcpu_array, then requests a file descriptor. If create_vcpu_fd() fails, newly inserted vcpu is removed from the vcpu_array, then destroyed: vcpu->vcpu_idx = atomic_read(&kvm->online_vcpus); r = xa_insert(&kvm->vcpu_array, vcpu->vcpu_idx, vcpu, GFP_KERNEL_ACCOUNT); kvm_get_kvm(kvm); r = create_vcpu_fd(vcpu); if (r < 0) { xa_erase(&kvm->vcpu_array, vcpu->vcpu_idx); kvm_put_kvm_no_destroy(kvm); goto unlock_vcpu_destroy; } atomic_inc(&kvm->online_vcpus); This results in a possible race condition when a reference to a vcpu is acquired (via kvm_get_vcpu() or kvm_for_each_vcpu()) moments before said vcpu is destroyed. Signed-off-by: Michal Luczaj <mhal@rbox.co> Message-Id: <20230510140410.1093987-2-mhal@rbox.co> Cc: stable@vger.kernel.org Fixes: c5b077549136 ("KVM: Convert the kvm->vcpus array to a xarray", 2021-12-08) Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: Don't enable hardware after a restart/shutdown is initiatedSean Christopherson2023-05-191-1/+16
| | | | | | | | | | | | | | | | | | | | | Reject hardware enabling, i.e. VM creation, if a restart/shutdown has been initiated to avoid re-enabling hardware between kvm_reboot() and machine_{halt,power_off,restart}(). The restart case is especially problematic (for x86) as enabling VMX (or clearing GIF in KVM_RUN on SVM) blocks INIT, which results in the restart/reboot hanging as BIOS is unable to wake and rendezvous with APs. Note, this bug, and the original issue that motivated the addition of kvm_reboot(), is effectively limited to a forced reboot, e.g. `reboot -f`. In a "normal" reboot, userspace will gracefully teardown userspace before triggering the kernel reboot (modulo bugs, errors, etc), i.e. any process that might do ioctl(KVM_CREATE_VM) is long gone. Fixes: 8e1c18157d87 ("KVM: VMX: Disable VMX when system shutdown") Signed-off-by: Sean Christopherson <seanjc@google.com> Acked-by: Marc Zyngier <maz@kernel.org> Message-Id: <20230512233127.804012-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: Use syscore_ops instead of reboot_notifier to hook restart/shutdownSean Christopherson2023-05-191-15/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use syscore_ops.shutdown to disable hardware virtualization during a reboot instead of using the dedicated reboot_notifier so that KVM disables virtualization _after_ system_state has been updated. This will allow fixing a race in KVM's handling of a forced reboot where KVM can end up enabling hardware virtualization between kernel_restart_prepare() and machine_restart(). Rename KVM's hook to match the syscore op to avoid any possible confusion from wiring up a "reboot" helper to a "shutdown" hook (neither "shutdown nor "reboot" is completely accurate as the hook handles both). Opportunistically rewrite kvm_shutdown()'s comment to make it less VMX specific, and to explain why kvm_rebooting exists. Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: James Morse <james.morse@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Zenghui Yu <yuzenghui@huawei.com> Cc: kvmarm@lists.linux.dev Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com> Cc: Anup Patel <anup@brainfault.org> Cc: Atish Patra <atishp@atishpatra.org> Cc: kvm-riscv@lists.infradead.org Signed-off-by: Sean Christopherson <seanjc@google.com> Acked-by: Marc Zyngier <maz@kernel.org> Message-Id: <20230512233127.804012-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds2023-05-011-16/+14
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull kvm updates from Paolo Bonzini: "s390: - More phys_to_virt conversions - Improvement of AP management for VSIE (nested virtualization) ARM64: - Numerous fixes for the pathological lock inversion issue that plagued KVM/arm64 since... forever. - New framework allowing SMCCC-compliant hypercalls to be forwarded to userspace, hopefully paving the way for some more features being moved to VMMs rather than be implemented in the kernel. - Large rework of the timer code to allow a VM-wide offset to be applied to both virtual and physical counters as well as a per-timer, per-vcpu offset that complements the global one. This last part allows the NV timer code to be implemented on top. - A small set of fixes to make sure that we don't change anything affecting the EL1&0 translation regime just after having having taken an exception to EL2 until we have executed a DSB. This ensures that speculative walks started in EL1&0 have completed. - The usual selftest fixes and improvements. x86: - Optimize CR0.WP toggling by avoiding an MMU reload when TDP is enabled, and by giving the guest control of CR0.WP when EPT is enabled on VMX (VMX-only because SVM doesn't support per-bit controls) - Add CR0/CR4 helpers to query single bits, and clean up related code where KVM was interpreting kvm_read_cr4_bits()'s "unsigned long" return as a bool - Move AMD_PSFD to cpufeatures.h and purge KVM's definition - Avoid unnecessary writes+flushes when the guest is only adding new PTEs - Overhaul .sync_page() and .invlpg() to utilize .sync_page()'s optimizations when emulating invalidations - Clean up the range-based flushing APIs - Revamp the TDP MMU's reaping of Accessed/Dirty bits to clear a single A/D bit using a LOCK AND instead of XCHG, and skip all of the "handle changed SPTE" overhead associated with writing the entire entry - Track the number of "tail" entries in a pte_list_desc to avoid having to walk (potentially) all descriptors during insertion and deletion, which gets quite expensive if the guest is spamming fork() - Disallow virtualizing legacy LBRs if architectural LBRs are available, the two are mutually exclusive in hardware - Disallow writes to immutable feature MSRs (notably PERF_CAPABILITIES) after KVM_RUN, similar to CPUID features - Overhaul the vmx_pmu_caps selftest to better validate PERF_CAPABILITIES - Apply PMU filters to emulated events and add test coverage to the pmu_event_filter selftest - AMD SVM: - Add support for virtual NMIs - Fixes for edge cases related to virtual interrupts - Intel AMX: - Don't advertise XTILE_CFG in KVM_GET_SUPPORTED_CPUID if XTILE_DATA is not being reported due to userspace not opting in via prctl() - Fix a bug in emulation of ENCLS in compatibility mode - Allow emulation of NOP and PAUSE for L2 - AMX selftests improvements - Misc cleanups MIPS: - Constify MIPS's internal callbacks (a leftover from the hardware enabling rework that landed in 6.3) Generic: - Drop unnecessary casts from "void *" throughout kvm_main.c - Tweak the layout of "struct kvm_mmu_memory_cache" to shrink the struct size by 8 bytes on 64-bit kernels by utilizing a padding hole Documentation: - Fix goof introduced by the conversion to rST" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (211 commits) KVM: s390: pci: fix virtual-physical confusion on module unload/load KVM: s390: vsie: clarifications on setting the APCB KVM: s390: interrupt: fix virtual-physical confusion for next alert GISA KVM: arm64: Have kvm_psci_vcpu_on() use WRITE_ONCE() to update mp_state KVM: arm64: Acquire mp_state_lock in kvm_arch_vcpu_ioctl_vcpu_init() KVM: selftests: Test the PMU event "Instructions retired" KVM: selftests: Copy full counter values from guest in PMU event filter test KVM: selftests: Use error codes to signal errors in PMU event filter test KVM: selftests: Print detailed info in PMU event filter asserts KVM: selftests: Add helpers for PMC asserts in PMU event filter test KVM: selftests: Add a common helper for the PMU event filter guest code KVM: selftests: Fix spelling mistake "perrmited" -> "permitted" KVM: arm64: vhe: Drop extra isb() on guest exit KVM: arm64: vhe: Synchronise with page table walker on MMU update KVM: arm64: pkvm: Document the side effects of kvm_flush_dcache_to_poc() KVM: arm64: nvhe: Synchronise with page table walker on TLBI KVM: arm64: Handle 32bit CNTPCTSS traps KVM: arm64: nvhe: Synchronise with page table walker on vcpu run KVM: arm64: vgic: Don't acquire its_lock before config_lock KVM: selftests: Add test to verify KVM's supported XCR0 ...
| * KVM: Fix comments that refer to the non-existent install_new_memslots()Jun Miao2023-03-241-7/+7
| | | | | | | | | | | | | | | | | | | | | | Fix stale comments that were left behind when install_new_memslots() was replaced by kvm_swap_active_memslots() as part of the scalable memslots rework. Fixes: a54d806688fe ("KVM: Keep memslots in tree-based structures instead of array-based ones") Signed-off-by: Jun Miao <jun.miao@intel.com> Link: https://lore.kernel.org/r/20230223052851.1054799-1-jun.miao@intel.com Signed-off-by: Sean Christopherson <seanjc@google.com>
| * kvm: kvm_main: Remove unnecessary (void*) conversionsLi kunyu2023-03-231-7/+5
| | | | | | | | | | | | | | | | void * pointer assignment does not require a forced replacement. Signed-off-by: Li kunyu <kunyu@nfschina.com> Link: https://lore.kernel.org/r/20221213080236.3969-1-kunyu@nfschina.com Signed-off-by: Sean Christopherson <seanjc@google.com>
| * KVM: Standardize on "int" return types instead of "long" in kvm_main.cThomas Huth2023-03-161-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | KVM functions use "long" return values for functions that are wired up to "struct file_operations", but otherwise use "int" return values for functions that can return 0/-errno in order to avoid unintentional divergences between 32-bit and 64-bit kernels. Some code still uses "long" in unnecessary spots, though, which can cause a little bit of confusion and unnecessary size casts. Let's change these spots to use "int" types, too. Signed-off-by: Thomas Huth <thuth@redhat.com> Message-Id: <20230208140105.655814-6-thuth@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | Merge tag 'smp-core-2023-04-27' of ↵Linus Torvalds2023-04-281-0/+3
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull SMP cross-CPU function-call updates from Ingo Molnar: - Remove diagnostics and adjust config for CSD lock diagnostics - Add a generic IPI-sending tracepoint, as currently there's no easy way to instrument IPI origins: it's arch dependent and for some major architectures it's not even consistently available. * tag 'smp-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: trace,smp: Trace all smp_function_call*() invocations trace: Add trace_ipi_send_cpu() sched, smp: Trace smp callback causing an IPI smp: reword smp call IPI comment treewide: Trace IPIs sent via smp_send_reschedule() irq_work: Trace self-IPIs sent via arch_irq_work_raise() smp: Trace IPIs sent via arch_send_call_function_ipi_mask() sched, smp: Trace IPIs sent via send_call_function_single_ipi() trace: Add trace_ipi_send_cpumask() kernel/smp: Make csdlock_debug= resettable locking/csd_lock: Remove per-CPU data indirection from CSD lock debugging locking/csd_lock: Remove added data from CSD lock debugging locking/csd_lock: Add Kconfig option for csd_debug default
| * | treewide: Trace IPIs sent via smp_send_reschedule()Valentin Schneider2023-03-241-0/+3
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To be able to trace invocations of smp_send_reschedule(), rename the arch-specific definitions of it to arch_smp_send_reschedule() and wrap it into an smp_send_reschedule() that contains a tracepoint. Changes to include the declaration of the tracepoint were driven by the following coccinelle script: @func_use@ @@ smp_send_reschedule(...); @include@ @@ #include <trace/events/ipi.h> @no_include depends on func_use && !include@ @@ #include <...> + + #include <trace/events/ipi.h> [csky bits] [riscv bits] Signed-off-by: Valentin Schneider <vschneid@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Guo Ren <guoren@kernel.org> Acked-by: Palmer Dabbelt <palmer@rivosinc.com> Link: https://lore.kernel.org/r/20230307143558.294354-6-vschneid@redhat.com
* | KVM: PPC: Make KVM_CAP_IRQFD_RESAMPLE platform dependentAlexey Kardashevskiy2023-03-311-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When introduced, IRQFD resampling worked on POWER8 with XICS. However KVM on POWER9 has never implemented it - the compatibility mode code ("XICS-on-XIVE") misses the kvm_notify_acked_irq() call and the native XIVE mode does not handle INTx in KVM at all. This moved the capability support advertising to platforms and stops advertising it on XIVE, i.e. POWER9 and later. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Acked-by: Anup Patel <anup@brainfault.org> Acked-by: Nicholas Piggin <npiggin@gmail.com> Message-Id: <20220504074807.3616813-1-aik@ozlabs.ru> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | KVM: x86/ioapic: Resample the pending state of an IRQ when unmaskingDmytro Maluka2023-03-271-6/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | KVM irqfd based emulation of level-triggered interrupts doesn't work quite correctly in some cases, particularly in the case of interrupts that are handled in a Linux guest as oneshot interrupts (IRQF_ONESHOT). Such an interrupt is acked to the device in its threaded irq handler, i.e. later than it is acked to the interrupt controller (EOI at the end of hardirq), not earlier. Linux keeps such interrupt masked until its threaded handler finishes, to prevent the EOI from re-asserting an unacknowledged interrupt. However, with KVM + vfio (or whatever is listening on the resamplefd) we always notify resamplefd at the EOI, so vfio prematurely unmasks the host physical IRQ, thus a new physical interrupt is fired in the host. This extra interrupt in the host is not a problem per se. The problem is that it is unconditionally queued for injection into the guest, so the guest sees an extra bogus interrupt. [*] There are observed at least 2 user-visible issues caused by those extra erroneous interrupts for a oneshot irq in the guest: 1. System suspend aborted due to a pending wakeup interrupt from ChromeOS EC (drivers/platform/chrome/cros_ec.c). 2. Annoying "invalid report id data" errors from ELAN0000 touchpad (drivers/input/mouse/elan_i2c_core.c), flooding the guest dmesg every time the touchpad is touched. The core issue here is that by the time when the guest unmasks the IRQ, the physical IRQ line is no longer asserted (since the guest has acked the interrupt to the device in the meantime), yet we unconditionally inject the interrupt queued into the guest by the previous resampling. So to fix the issue, we need a way to detect that the IRQ is no longer pending, and cancel the queued interrupt in this case. With IOAPIC we are not able to probe the physical IRQ line state directly (at least not if the underlying physical interrupt controller is an IOAPIC too), so in this patch we use irqfd resampler for that. Namely, instead of injecting the queued interrupt, we just notify the resampler that this interrupt is done. If the IRQ line is actually already deasserted, we are done. If it is still asserted, a new interrupt will be shortly triggered through irqfd and injected into the guest. In the case if there is no irqfd resampler registered for this IRQ, we cannot fix the issue, so we keep the existing behavior: immediately unconditionally inject the queued interrupt. This patch fixes the issue for x86 IOAPIC only. In the long run, we can fix it for other irqchips and other architectures too, possibly taking advantage of reading the physical state of the IRQ line, which is possible with some other irqchips (e.g. with arm64 GIC, maybe even with the legacy x86 PIC). [*] In this description we assume that the interrupt is a physical host interrupt forwarded to the guest e.g. by vfio. Potentially the same issue may occur also with a purely virtual interrupt from an emulated device, e.g. if the guest handles this interrupt, again, as a oneshot interrupt. Signed-off-by: Dmytro Maluka <dmy@semihalf.com> Link: https://lore.kernel.org/kvm/31420943-8c5f-125c-a5ee-d2fde2700083@semihalf.com/ Link: https://lore.kernel.org/lkml/87o7wrug0w.wl-maz@kernel.org/ Message-Id: <20230322204344.50138-3-dmy@semihalf.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | KVM: irqfd: Make resampler_list an RCU listDmytro Maluka2023-03-271-2/+6
|/ | | | | | | | | | | | | | | | | | It is useful to be able to do read-only traversal of the list of all the registered irqfd resamplers without locking the resampler_lock mutex. In particular, we are going to traverse it to search for a resampler registered for the given irq of an irqchip, and that will be done with an irqchip spinlock (ioapic->lock) held, so it is undesirable to lock a mutex in this context. So turn this list into an RCU list. For protecting the read side, reuse kvm->irq_srcu which is already used for protecting a number of irq related things (kvm->irq_routing, irqfd->resampler->list, kvm->irq_ack_notifier_list, kvm->arch.mask_notifier_list). Signed-off-by: Dmytro Maluka <dmy@semihalf.com> Message-Id: <20230322204344.50138-2-dmy@semihalf.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* Merge tag 'kvm-riscv-6.3-1' of https://github.com/kvm-riscv/linux into HEADPaolo Bonzini2023-02-151-3/+3
|\ | | | | | | | | | | | | | | | | KVM/riscv changes for 6.3 - Fix wrong usage of PGDIR_SIZE to check page sizes - Fix privilege mode setting in kvm_riscv_vcpu_trap_redirect() - Redirect illegal instruction traps to guest - SBI PMU support for guest
| * Merge tag 'vfio-v6.2-rc6' of https://github.com/awilliam/linux-vfioLinus Torvalds2023-01-231-3/+3
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull VFIO fixes from Alex Williamson: - Honor reserved regions when testing for IOMMU find grained super page support, avoiding a regression on s390 for a firmware device where the existence of the mapping, even if unused can trigger an error state. (Niklas Schnelle) - Fix a deadlock in releasing KVM references by using the alternate .release() rather than .destroy() callback for the kvm-vfio device. (Yi Liu) * tag 'vfio-v6.2-rc6' of https://github.com/awilliam/linux-vfio: kvm/vfio: Fix potential deadlock on vfio group_lock vfio/type1: Respect IOMMU reserved regions in vfio_test_domain_fgsp()
| | * kvm/vfio: Fix potential deadlock on vfio group_lockYi Liu2023-01-201-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently it is possible that the final put of a KVM reference comes from vfio during its device close operation. This occurs while the vfio group lock is held; however, if the vfio device is still in the kvm device list, then the following call chain could result in a deadlock: VFIO holds group->group_lock/group_rwsem -> kvm_put_kvm -> kvm_destroy_vm -> kvm_destroy_devices -> kvm_vfio_destroy -> kvm_vfio_file_set_kvm -> vfio_file_set_kvm -> try to hold group->group_lock/group_rwsem The key function is the kvm_destroy_devices() which triggers destroy cb of kvm_device_ops. It calls back to vfio and try to hold group_lock. So if this path doesn't call back to vfio, this dead lock would be fixed. Actually, there is a way for it. KVM provides another point to free the kvm-vfio device which is the point when the device file descriptor is closed. This can be achieved by providing the release cb instead of the destroy cb. Also rename kvm_vfio_destroy() to be kvm_vfio_release(). /* * Destroy is responsible for freeing dev. * * Destroy may be called before or after destructors are called * on emulated I/O regions, depending on whether a reference is * held by a vcpu or other kvm component that gets destroyed * after the emulated I/O. */ void (*destroy)(struct kvm_device *dev); /* * Release is an alternative method to free the device. It is * called when the device file descriptor is closed. Once * release is called, the destroy method will not be called * anymore as the device is removed from the device list of * the VM. kvm->lock is held. */ void (*release)(struct kvm_device *dev); Fixes: 421cfe6596f6 ("vfio: remove VFIO_GROUP_NOTIFY_SET_KVM") Reported-by: Alex Williamson <alex.williamson@redhat.com> Suggested-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Yi Liu <yi.l.liu@intel.com> Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> Link: https://lore.kernel.org/r/20230114000351.115444-1-mjrosato@linux.ibm.com Link: https://lore.kernel.org/r/20230120150528.471752-1-yi.l.liu@intel.com [aw: update comment as well, s/destroy/release/] Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
* | | KVM: Destroy target device if coalesced MMIO unregistration failsSean Christopherson2023-02-011-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Destroy and free the target coalesced MMIO device if unregistering said device fails. As clearly noted in the code, kvm_io_bus_unregister_dev() does not destroy the target device. BUG: memory leak unreferenced object 0xffff888112a54880 (size 64): comm "syz-executor.2", pid 5258, jiffies 4297861402 (age 14.129s) hex dump (first 32 bytes): 38 c7 67 15 00 c9 ff ff 38 c7 67 15 00 c9 ff ff 8.g.....8.g..... e0 c7 e1 83 ff ff ff ff 00 30 67 15 00 c9 ff ff .........0g..... backtrace: [<0000000006995a8a>] kmalloc include/linux/slab.h:556 [inline] [<0000000006995a8a>] kzalloc include/linux/slab.h:690 [inline] [<0000000006995a8a>] kvm_vm_ioctl_register_coalesced_mmio+0x8e/0x3d0 arch/x86/kvm/../../../virt/kvm/coalesced_mmio.c:150 [<00000000022550c2>] kvm_vm_ioctl+0x47d/0x1600 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3323 [<000000008a75102f>] vfs_ioctl fs/ioctl.c:46 [inline] [<000000008a75102f>] file_ioctl fs/ioctl.c:509 [inline] [<000000008a75102f>] do_vfs_ioctl+0xbab/0x1160 fs/ioctl.c:696 [<0000000080e3f669>] ksys_ioctl+0x76/0xa0 fs/ioctl.c:713 [<0000000059ef4888>] __do_sys_ioctl fs/ioctl.c:720 [inline] [<0000000059ef4888>] __se_sys_ioctl fs/ioctl.c:718 [inline] [<0000000059ef4888>] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718 [<000000006444fa05>] do_syscall_64+0x9f/0x4e0 arch/x86/entry/common.c:290 [<000000009a4ed50b>] entry_SYSCALL_64_after_hwframe+0x49/0xbe BUG: leak checking failed Fixes: 5d3c4c79384a ("KVM: Stop looking for coalesced MMIO zones if the bus is destroyed") Cc: stable@vger.kernel.org Reported-by: 柳菁峰 <liujingfeng@qianxin.com> Reported-by: Michal Luczaj <mhal@rbox.co> Link: https://lore.kernel.org/r/20221219171924.67989-1-seanjc@google.com Link: https://lore.kernel.org/all/20230118220003.1239032-1-mhal@rbox.co Signed-off-by: Sean Christopherson <seanjc@google.com>
* | | Merge branch 'kvm-v6.2-rc4-fixes' into HEADPaolo Bonzini2023-01-241-0/+7
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ARM: * Fix the PMCR_EL0 reset value after the PMU rework * Correctly handle S2 fault triggered by a S1 page table walk by not always classifying it as a write, as this breaks on R/O memslots * Document why we cannot exit with KVM_EXIT_MMIO when taking a write fault from a S1 PTW on a R/O memslot * Put the Apple M2 on the naughty list for not being able to correctly implement the vgic SEIS feature, just like the M1 before it * Reviewer updates: Alex is stepping down, replaced by Zenghui x86: * Fix various rare locking issues in Xen emulation and teach lockdep to detect them * Documentation improvements * Do not return host topology information from KVM_GET_SUPPORTED_CPUID
| * | KVM: Ensure lockdep knows about kvm->lock vs. vcpu->mutex ordering ruleDavid Woodhouse2023-01-111-0/+7
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | Documentation/virt/kvm/locking.rst tells us that kvm->lock is taken outside vcpu->mutex. But that doesn't actually happen very often; it's only in some esoteric cases like migration with AMD SEV. This means that lockdep usually doesn't notice, and doesn't do its job of keeping us honest. Ensure that lockdep *always* knows about the ordering of these two locks, by briefly taking vcpu->mutex in kvm_vm_ioctl_create_vcpu() while kvm->lock is held. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20230111180651.14394-3-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * Merge branch 'kvm-late-6.1-fixes' into HEADPaolo Bonzini2022-12-281-4/+0
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | x86: * several fixes to nested VMX execution controls * fixes and clarification to the documentation for Xen emulation * do not unnecessarily release a pmu event with zero period * MMU fixes * fix Coverity warning in kvm_hv_flush_tlb() selftests: * fixes for the ucall mechanism in selftests * other fixes mostly related to compilation with clang
* | | KVM: Clean up error labels in kvm_init()Sean Christopherson2022-12-291-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert the last two "out" lables to "err" labels now that the dust has settled, i.e. now that there are no more planned changes to the order of things in kvm_init(). Use "err" instead of "out" as it's easier to describe what failed than it is to describe what needs to be unwound, e.g. if allocating a per-CPU kick mask fails, KVM needs to free any masks that were allocated, and of course needs to unwind previous operations. Reported-by: Chao Gao <chao.gao@intel.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-51-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Opt out of generic hardware enabling on s390 and PPCSean Christopherson2022-12-292-6/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow architectures to opt out of the generic hardware enabling logic, and opt out on both s390 and PPC, which don't need to manually enable virtualization as it's always on (when available). In addition to letting s390 and PPC drop a bit of dead code, this will hopefully also allow ARM to clean up its related code, e.g. ARM has its own per-CPU flag to track which CPUs have enable hardware due to the need to keep hardware enabled indefinitely when pKVM is enabled. Signed-off-by: Sean Christopherson <seanjc@google.com> Acked-by: Anup Patel <anup@brainfault.org> Message-Id: <20221130230934.1014142-50-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Register syscore (suspend/resume) ops early in kvm_init()Sean Christopherson2022-12-291-34/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Register the suspend/resume notifier hooks at the same time KVM registers its reboot notifier so that all the code in kvm_init() that deals with enabling/disabling hardware is bundled together. Opportunstically move KVM's implementations to reside near the reboot notifier code for the same reason. Bunching the code together will allow architectures to opt out of KVM's generic hardware enable/disable logic with minimal #ifdeffery. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-49-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Make hardware_enable_failed a local variable in the "enable all" pathIsaku Yamahata2022-12-291-19/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rework detecting hardware enabling errors to use a local variable in the "enable all" path to track whether or not enabling was successful across all CPUs. Using a global variable complicates paths that enable hardware only on the current CPU, e.g. kvm_resume() and kvm_online_cpu(). Opportunistically add a WARN if hardware enabling fails during kvm_resume(), KVM is all kinds of hosed if CPU0 fails to enable hardware. The WARN is largely futile in the current code, as KVM BUG()s on spurious faults on VMX instructions, e.g. attempting to run a vCPU on CPU if hardware enabling fails will explode. ------------[ cut here ]------------ kernel BUG at arch/x86/kvm/x86.c:508! invalid opcode: 0000 [#1] SMP CPU: 3 PID: 1009 Comm: CPU 4/KVM Not tainted 6.1.0-rc1+ #11 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:kvm_spurious_fault+0xa/0x10 Call Trace: vmx_vcpu_load_vmcs+0x192/0x230 [kvm_intel] vmx_vcpu_load+0x16/0x60 [kvm_intel] kvm_arch_vcpu_load+0x32/0x1f0 vcpu_load+0x2f/0x40 kvm_arch_vcpu_ioctl_run+0x19/0x9d0 kvm_vcpu_ioctl+0x271/0x660 __x64_sys_ioctl+0x80/0xb0 do_syscall_64+0x2b/0x50 entry_SYSCALL_64_after_hwframe+0x46/0xb0 But, the WARN may provide a breadcrumb to understand what went awry, and someday KVM may fix one or both of those bugs, e.g. by finding a way to eat spurious faults no matter the context (easier said than done due to side effects of certain operations, e.g. Intel's VMCLEAR). Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> [sean: rebase, WARN on failure in kvm_resume()] Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-48-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Use a per-CPU variable to track which CPUs have enabled virtualizationSean Christopherson2022-12-291-23/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use a per-CPU variable instead of a shared bitmap to track which CPUs have successfully enabled virtualization hardware. Using a per-CPU bool avoids the need for an additional allocation, and arguably yields easier to read code. Using a bitmap would be advantageous if KVM used it to avoid generating IPIs to CPUs that failed to enable hardware, but that's an extreme edge case and not worth optimizing, and the low level helpers would still want to keep their individual checks as attempting to enable virtualization hardware when it's already enabled can be problematic, e.g. Intel's VMXON will fault. Opportunistically change the order in hardware_enable_nolock() to set the flag if and only if hardware enabling is successful, instead of speculatively setting the flag and then clearing it on failure. Add a comment explaining that the check in hardware_disable_nolock() isn't simply paranoia. Waaay back when, commit 1b6c016818a5 ("KVM: Keep track of which cpus have virtualization enabled"), added the logic as a guards against CPU hotplug racing with hardware enable/disable. Now that KVM has eliminated the race by taking cpu_hotplug_lock for read (via cpus_read_lock()) when enabling or disabling hardware, at first glance it appears that the check is now superfluous, i.e. it's tempting to remove the per-CPU flag entirely... Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-47-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Remove on_each_cpu(hardware_disable_nolock) in kvm_exit()Isaku Yamahata2022-12-291-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Drop the superfluous invocation of hardware_disable_nolock() during kvm_exit(), as it's nothing more than a glorified nop. KVM automatically disables hardware on all CPUs when the last VM is destroyed, and kvm_exit() cannot be called until the last VM goes away as the calling module is pinned by an elevated refcount of the fops associated with /dev/kvm. This holds true even on x86, where the caller of kvm_exit() is not kvm.ko, but is instead a dependent module, kvm_amd.ko or kvm_intel.ko, as kvm_chardev_ops.owner is set to the module that calls kvm_init(), not hardcoded to the base kvm.ko module. Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> [sean: rework changelog] Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-46-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Drop kvm_count_lock and instead protect kvm_usage_count with kvm_lockIsaku Yamahata2022-12-291-12/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Drop kvm_count_lock and instead protect kvm_usage_count with kvm_lock now that KVM hooks CPU hotplug during the ONLINE phase, which can sleep. Previously, KVM hooked the STARTING phase, which is not allowed to sleep and thus could not take kvm_lock (a mutex). This effectively allows the task that's initiating hardware enabling/disabling to preempted and/or migrated. Note, the Documentation/virt/kvm/locking.rst statement that kvm_count_lock is "raw" because hardware enabling/disabling needs to be atomic with respect to migration is wrong on multiple fronts. First, while regular spinlocks can be preempted, the task holding the lock cannot be migrated. Second, preventing migration is not required. on_each_cpu() disables preemption, which ensures that cpus_hardware_enabled correctly reflects hardware state. The task may be preempted/migrated between bumping kvm_usage_count and invoking on_each_cpu(), but that's perfectly ok as kvm_usage_count is still protected, e.g. other tasks that call hardware_enable_all() will be blocked until the preempted/migrated owner exits its critical section. KVM does have lockless accesses to kvm_usage_count in the suspend/resume flows, but those are safe because all tasks must be frozen prior to suspending CPUs, and a task cannot be frozen while it holds one or more locks (userspace tasks are frozen via a fake signal). Preemption doesn't need to be explicitly disabled in the hotplug path. The hotplug thread is pinned to the CPU that's being hotplugged, and KVM only cares about having a stable CPU, i.e. to ensure hardware is enabled on the correct CPU. Lockep, i.e. check_preemption_disabled(), plays nice with this state too, as is_percpu_thread() is true for the hotplug thread. Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> Co-developed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-45-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Ensure CPU is stable during low level hardware enable/disableSean Christopherson2022-12-291-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use the non-raw smp_processor_id() in the low hardware enable/disable helpers as KVM absolutely relies on the CPU being stable, e.g. KVM would end up with incorrect state if the task were migrated between accessing cpus_hardware_enabled and actually enabling/disabling hardware. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-44-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Disable CPU hotplug during hardware enabling/disablingChao Gao2022-12-291-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Disable CPU hotplug when enabling/disabling hardware to prevent the corner case where if the following sequence occurs: 1. A hotplugged CPU marks itself online in cpu_online_mask 2. The hotplugged CPU enables interrupt before invoking KVM's ONLINE callback 3 hardware_{en,dis}able_all() is invoked on another CPU the hotplugged CPU will be included in on_each_cpu() and thus get sent through hardware_{en,dis}able_nolock() before kvm_online_cpu() is called. start_secondary { ... set_cpu_online(smp_processor_id(), true); <- 1 ... local_irq_enable(); <- 2 ... cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); <- 3 } KVM currently fudges around this race by keeping track of which CPUs have done hardware enabling (see commit 1b6c016818a5 "KVM: Keep track of which cpus have virtualization enabled"), but that's an inefficient, convoluted, and hacky solution. Signed-off-by: Chao Gao <chao.gao@intel.com> [sean: split to separate patch, write changelog] Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-43-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Rename and move CPUHP_AP_KVM_STARTING to ONLINE sectionChao Gao2022-12-291-8/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The CPU STARTING section doesn't allow callbacks to fail. Move KVM's hotplug callback to ONLINE section so that it can abort onlining a CPU in certain cases to avoid potentially breaking VMs running on existing CPUs. For example, when KVM fails to enable hardware virtualization on the hotplugged CPU. Place KVM's hotplug state before CPUHP_AP_SCHED_WAIT_EMPTY as it ensures when offlining a CPU, all user tasks and non-pinned kernel tasks have left the CPU, i.e. there cannot be a vCPU task around. So, it is safe for KVM's CPU offline callback to disable hardware virtualization at that point. Likewise, KVM's online callback can enable hardware virtualization before any vCPU task gets a chance to run on hotplugged CPUs. Drop kvm_x86_check_processor_compatibility()'s WARN that IRQs are disabled, as the ONLINE section runs with IRQs disabled. The WARN wasn't intended to be a requirement, e.g. disabling preemption is sufficient, the IRQ thing was purely an aggressive sanity check since the helper was only ever invoked via SMP function call. Rename KVM's CPU hotplug callbacks accordingly. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Chao Gao <chao.gao@intel.com> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> Reviewed-by: Yuan Yao <yuan.yao@intel.com> [sean: drop WARN that IRQs are disabled] Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-42-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Drop kvm_arch_check_processor_compat() hookSean Christopherson2022-12-291-23/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Drop kvm_arch_check_processor_compat() and its support code now that all architecture implementations are nops. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Eric Farman <farman@linux.ibm.com> # s390 Acked-by: Anup Patel <anup@brainfault.org> Reviewed-by: Kai Huang <kai.huang@intel.com> Message-Id: <20221130230934.1014142-33-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Drop kvm_arch_{init,exit}() hooksSean Christopherson2022-12-291-17/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Drop kvm_arch_init() and kvm_arch_exit() now that all implementations are nops. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Eric Farman <farman@linux.ibm.com> # s390 Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Acked-by: Anup Patel <anup@brainfault.org> Message-Id: <20221130230934.1014142-30-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Drop arch hardware (un)setup hooksSean Christopherson2022-12-291-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Drop kvm_arch_hardware_setup() and kvm_arch_hardware_unsetup() now that all implementations are nops. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Eric Farman <farman@linux.ibm.com> # s390 Acked-by: Anup Patel <anup@brainfault.org> Message-Id: <20221130230934.1014142-10-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Teardown VFIO ops earlier in kvm_exit()Sean Christopherson2022-12-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the call to kvm_vfio_ops_exit() further up kvm_exit() to try and bring some amount of symmetry to the setup order in kvm_init(), and more importantly so that the arch hooks are invoked dead last by kvm_exit(). This will allow arch code to move away from the arch hooks without any change in ordering between arch code and common code in kvm_exit(). That kvm_vfio_ops_exit() is called last appears to be 100% arbitrary. It was bolted on after the fact by commit 571ee1b68598 ("kvm: vfio: fix unregister kvm_device_ops of vfio"). The nullified kvm_device_ops_table is also local to kvm_main.c and is used only when there are active VMs, so unless arch code is doing something truly bizarre, nullifying the table earlier in kvm_exit() is little more than a nop. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Eric Farman <farman@linux.ibm.com> Message-Id: <20221130230934.1014142-5-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Allocate cpus_hardware_enabled after arch hardware setupSean Christopherson2022-12-291-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allocate cpus_hardware_enabled after arch hardware setup so that arch "init" and "hardware setup" are called back-to-back and thus can be combined in a future patch. cpus_hardware_enabled is never used before kvm_create_vm(), i.e. doesn't have a dependency with hardware setup and only needs to be allocated before /dev/kvm is exposed to userspace. Free the object before the arch hooks are invoked to maintain symmetry, and so that arch code can move away from the hooks without having to worry about ordering changes. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Yuan Yao <yuan.yao@intel.com> Message-Id: <20221130230934.1014142-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Initialize IRQ FD after arch hardware setupSean Christopherson2022-12-291-18/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move initialization of KVM's IRQ FD workqueue below arch hardware setup as a step towards consolidating arch "init" and "hardware setup", and eventually towards dropping the hooks entirely. There is no dependency on the workqueue being created before hardware setup, the workqueue is used only when destroying VMs, i.e. only needs to be created before /dev/kvm is exposed to userspace. Move the destruction of the workqueue before the arch hooks to maintain symmetry, and so that arch code can move away from the hooks without having to worry about ordering changes. Reword the comment about kvm_irqfd_init() needing to come after kvm_arch_init() to call out that kvm_arch_init() must come before common KVM does _anything_, as x86 very subtly relies on that behavior to deal with multiple calls to kvm_init(), e.g. if userspace attempts to load kvm_amd.ko and kvm_intel.ko. Tag the code with a FIXME, as x86's subtle requirement is gross, and invoking an arch callback as the very first action in a helper that is called only from arch code is silly. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | KVM: Register /dev/kvm as the _very_ last thing during initializationSean Christopherson2022-12-291-9/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Register /dev/kvm, i.e. expose KVM to userspace, only after all other setup has completed. Once /dev/kvm is exposed, userspace can start invoking KVM ioctls, creating VMs, etc... If userspace creates a VM before KVM is done with its configuration, bad things may happen, e.g. KVM will fail to properly migrate vCPU state if a VM is created before KVM has registered preemption notifiers. Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221130230934.1014142-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | | Merge branch 'kvm-late-6.1' into HEADPaolo Bonzini2022-12-291-4/+0
|\ \ \ | |/ / |/| / | |/ | | | | | | | | | | | | | | | | | | | | | | | | x86: * Change tdp_mmu to a read-only parameter * Separate TDP and shadow MMU page fault paths * Enable Hyper-V invariant TSC control selftests: * Use TAP interface for kvm_binary_stats_test and tsc_msrs_test Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * kvm: Remove the unused macro KVM_MMU_READ_{,UN}LOCK()Lai Jiangshan2022-12-271-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | No code is using KVM_MMU_READ_LOCK() or KVM_MMU_READ_UNLOCK(). They used to be in virt/kvm/pfncache.c: KVM_MMU_READ_LOCK(kvm); retry = mmu_notifier_retry_hva(kvm, mmu_seq, uhva); KVM_MMU_READ_UNLOCK(kvm); However, since 58cd407ca4c6 ("KVM: Fix multiple races in gfn=>pfn cache refresh", 2022-05-25) the code is only relying on the MMU notifier's invalidation count and sequence number. Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com> Message-Id: <20221207120617.9409-1-jiangshanlai@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds2022-12-156-92/+188
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull kvm updates from Paolo Bonzini: "ARM64: - 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 (see merge commit 382b5b87a97d: "Fix a number of issues with MTE, such as races on the tags being initialised vs the PG_mte_tagged flag as well as the lack of support for VM_SHARED when KVM is involved. Patches from Catalin Marinas and Peter Collingbourne"). - 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. - Pick a small set of documentation and spelling fixes, because no good merge window would be complete without those. s390: - Second batch of the lazy destroy patches - First batch of KVM changes for kernel virtual != physical address support - Removal of a unused function x86: - Allow compiling out SMM support - Cleanup and documentation of SMM state save area format - Preserve interrupt shadow in SMM state save area - Respond to generic signals during slow page faults - Fixes and optimizations for the non-executable huge page errata fix. - Reprogram all performance counters on PMU filter change - Cleanups to Hyper-V emulation and tests - Process Hyper-V TLB flushes from a nested guest (i.e. from a L2 guest running on top of a L1 Hyper-V hypervisor) - Advertise several new Intel features - x86 Xen-for-KVM: - Allow the Xen runstate information to cross a page boundary - Allow XEN_RUNSTATE_UPDATE flag behaviour to be configured - Add support for 32-bit guests in SCHEDOP_poll - Notable x86 fixes and cleanups: - One-off fixes for various emulation flows (SGX, VMXON, NRIPS=0). - Reinstate IBPB on emulated VM-Exit that was incorrectly dropped a few years back when eliminating unnecessary barriers when switching between vmcs01 and vmcs02. - Clean up vmread_error_trampoline() to make it more obvious that params must be passed on the stack, even for x86-64. - Let userspace set all supported bits in MSR_IA32_FEAT_CTL irrespective of the current guest CPUID. - Fudge around a race with TSC refinement that results in KVM incorrectly thinking a guest needs TSC scaling when running on a CPU with a constant TSC, but no hardware-enumerated TSC frequency. - Advertise (on AMD) that the SMM_CTL MSR is not supported - Remove unnecessary exports Generic: - Support for responding to signals during page faults; introduces new FOLL_INTERRUPTIBLE flag that was reviewed by mm folks Selftests: - Fix an inverted check in the access tracking perf test, and restore support for asserting that there aren't too many idle pages when running on bare metal. - Fix build errors that occur in certain setups (unsure exactly what is unique about the problematic setup) due to glibc overriding static_assert() to a variant that requires a custom message. - Introduce actual atomics for clear/set_bit() in selftests - Add support for pinning vCPUs in dirty_log_perf_test. - Rename the so called "perf_util" framework to "memstress". - Add a lightweight psuedo RNG for guest use, and use it to randomize the access pattern and write vs. read percentage in the memstress tests. - Add a common ucall implementation; code dedup and pre-work for running SEV (and beyond) guests in selftests. - Provide a common constructor and arch hook, which will eventually be used by x86 to automatically select the right hypercall (AMD vs. Intel). - A bunch of added/enabled/fixed selftests for ARM64, covering memslots, breakpoints, stage-2 faults and access tracking. - x86-specific selftest changes: - Clean up x86's page table management. - Clean up and enhance the "smaller maxphyaddr" test, and add a related test to cover generic emulation failure. - Clean up the nEPT support checks. - Add X86_PROPERTY_* framework to retrieve multi-bit CPUID values. - Fix an ordering issue in the AMX test introduced by recent conversions to use kvm_cpu_has(), and harden the code to guard against similar bugs in the future. Anything that tiggers caching of KVM's supported CPUID, kvm_cpu_has() in this case, effectively hides opt-in XSAVE features if the caching occurs before the test opts in via prctl(). Documentation: - Remove deleted ioctls from documentation - Clean up the docs for the x86 MSR filter. - Various fixes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (361 commits) KVM: x86: Add proper ReST tables for userspace MSR exits/flags KVM: selftests: Allocate ucall pool from MEM_REGION_DATA KVM: arm64: selftests: Align VA space allocator with TTBR0 KVM: arm64: Fix benign bug with incorrect use of VA_BITS KVM: arm64: PMU: Fix period computation for 64bit counters with 32bit overflow KVM: x86: Advertise that the SMM_CTL MSR is not supported KVM: x86: remove unnecessary exports KVM: selftests: Fix spelling mistake "probabalistic" -> "probabilistic" tools: KVM: selftests: Convert clear/set_bit() to actual atomics tools: Drop "atomic_" prefix from atomic test_and_set_bit() tools: Drop conflicting non-atomic test_and_{clear,set}_bit() helpers KVM: selftests: Use non-atomic clear/set bit helpers in KVM tests perf tools: Use dedicated non-atomic clear/set bit helpers tools: Take @bit as an "unsigned long" in {clear,set}_bit() helpers KVM: arm64: selftests: Enable single-step without a "full" ucall() KVM: x86: fix APICv/x2AVIC disabled when vm reboot by itself KVM: Remove stale comment about KVM_REQ_UNHALT KVM: Add missing arch for KVM_CREATE_DEVICE and KVM_{SET,GET}_DEVICE_ATTR KVM: Reference to kvm_userspace_memory_region in doc and comments KVM: Delete all references to removed KVM_SET_MEMORY_ALIAS ioctl ...
| * Merge remote-tracking branch 'kvm/queue' into HEADPaolo Bonzini2022-12-122-62/+54
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | x86 Xen-for-KVM: * Allow the Xen runstate information to cross a page boundary * Allow XEN_RUNSTATE_UPDATE flag behaviour to be configured * add support for 32-bit guests in SCHEDOP_poll x86 fixes: * One-off fixes for various emulation flows (SGX, VMXON, NRIPS=0). * Reinstate IBPB on emulated VM-Exit that was incorrectly dropped a few years back when eliminating unnecessary barriers when switching between vmcs01 and vmcs02. * Clean up the MSR filter docs. * Clean up vmread_error_trampoline() to make it more obvious that params must be passed on the stack, even for x86-64. * Let userspace set all supported bits in MSR_IA32_FEAT_CTL irrespective of the current guest CPUID. * Fudge around a race with TSC refinement that results in KVM incorrectly thinking a guest needs TSC scaling when running on a CPU with a constant TSC, but no hardware-enumerated TSC frequency. * Advertise (on AMD) that the SMM_CTL MSR is not supported * Remove unnecessary exports Selftests: * Fix an inverted check in the access tracking perf test, and restore support for asserting that there aren't too many idle pages when running on bare metal. * Fix an ordering issue in the AMX test introduced by recent conversions to use kvm_cpu_has(), and harden the code to guard against similar bugs in the future. Anything that tiggers caching of KVM's supported CPUID, kvm_cpu_has() in this case, effectively hides opt-in XSAVE features if the caching occurs before the test opts in via prctl(). * Fix build errors that occur in certain setups (unsure exactly what is unique about the problematic setup) due to glibc overriding static_assert() to a variant that requires a custom message. * Introduce actual atomics for clear/set_bit() in selftests Documentation: * Remove deleted ioctls from documentation * Various fixes
| | * Merge branch 'gpc-fixes' of git://git.infradead.org/users/dwmw2/linux into HEADPaolo Bonzini2022-12-021-54/+50
| | |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull Xen-for-KVM changes from David Woodhouse: * add support for 32-bit guests in SCHEDOP_poll * the rest of the gfn-to-pfn cache API cleanup "I still haven't reinstated the last of those patches to make gpc->len immutable." Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| | | * KVM: Skip unnecessary "unmap" if gpc is already valid during refreshSean Christopherson2022-11-301-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When refreshing a gfn=>pfn cache, skip straight to unlocking if the cache already valid instead of stuffing the "old" variables to turn the unmapping outro into a nop. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
| | | * KVM: Drop @gpa from exported gfn=>pfn cache check() and refresh() helpersSean Christopherson2022-11-301-6/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Drop the @gpa param from the exported check()+refresh() helpers and limit changing the cache's GPA to the activate path. All external users just feed in gpc->gpa, i.e. this is a fancy nop. Allowing users to change the GPA at check()+refresh() is dangerous as those helpers explicitly allow concurrent calls, e.g. KVM could get into a livelock scenario. It's also unclear as to what the expected behavior should be if multiple tasks attempt to refresh with different GPAs. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
| | | * KVM: Do not partially reinitialize gfn=>pfn cache during activationSean Christopherson2022-11-301-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Don't partially reinitialize a gfn=>pfn cache when activating the cache, and instead assert that the cache is not valid during activation. Bug the VM if the assertion fails, as use-after-free and/or data corruption is all but guaranteed if KVM ends up with a valid-but-inactive cache. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
| | | * KVM: Drop KVM's API to allow temporarily unmapping gfn=>pfn cacheSean Christopherson2022-11-301-28/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Drop kvm_gpc_unmap() as it has no users and unclear requirements. The API was added as part of the original gfn_to_pfn_cache support, but its sole usage[*] was never merged. Fold the guts of kvm_gpc_unmap() into the deactivate path and drop the API. Omit acquiring refresh_lock as as concurrent calls to kvm_gpc_deactivate() are not allowed (this is not enforced, e.g. via lockdep. due to it being called during vCPU destruction). If/when temporary unmapping makes a comeback, the desirable behavior is likely to restrict temporary unmapping to vCPU-exclusive mappings and require the vcpu->mutex be held to serialize unmap. Use of the refresh_lock to protect unmapping was somewhat specuatively added by commit 93984f19e7bc ("KVM: Fully serialize gfn=>pfn cache refresh via mutex") to guard against concurrent unmaps, but the primary use case of the temporary unmap, nested virtualization[*], doesn't actually need or want concurrent unmaps. [*] https://lore.kernel.org/all/20211210163625.2886-7-dwmw2@infradead.org Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
| | | * KVM: Use gfn_to_pfn_cache's immutable "kvm" in kvm_gpc_refresh()Michal Luczaj2022-11-301-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make kvm_gpc_refresh() use kvm instance cached in gfn_to_pfn_cache. No functional change intended. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Michal Luczaj <mhal@rbox.co> [sean: leave kvm_gpc_unmap() as-is] Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
| | | * KVM: Clean up hva_to_pfn_retry()Michal Luczaj2022-11-301-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make hva_to_pfn_retry() use kvm instance cached in gfn_to_pfn_cache. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Michal Luczaj <mhal@rbox.co> Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
| | | * KVM: Use gfn_to_pfn_cache's immutable "kvm" in kvm_gpc_check()Michal Luczaj2022-11-301-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make kvm_gpc_check() use kvm instance cached in gfn_to_pfn_cache. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Michal Luczaj <mhal@rbox.co> Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
| | | * KVM: Store immutable gfn_to_pfn_cache propertiesMichal Luczaj2022-11-301-8/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the assignment of immutable properties @kvm, @vcpu, and @usage to the initializer. Make _activate() and _deactivate() use stored values. Note, @len is also effectively immutable for most cases, but not in the case of the Xen runstate cache, which may be split across two pages and the length of the first segment will depend on its address. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Michal Luczaj <mhal@rbox.co> [sean: handle @len in a separate patch] Signed-off-by: Sean Christopherson <seanjc@google.com> [dwmw2: acknowledge that @len can actually change for some use cases] Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
| | * | KVM: Remove stale comment about KVM_REQ_UNHALTSean Christopherson2022-12-021-4/+0
| | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove a comment about KVM_REQ_UNHALT being set by kvm_vcpu_check_block() that was missed when KVM_REQ_UNHALT was dropped. Fixes: c59fb1275838 ("KVM: remove KVM_REQ_UNHALT") Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221201220433.31366-1-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-02 01:29:41 +0000