user/sven/linux.git/include/linux/kvm_host.h, branch v6.3.12

KVM: x86/ioapic: Resample the pending state of an IRQ when unmasking

2023-03-27T14:13:28Z

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 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

KVM: irqfd: Make resampler_list an RCU list

2023-03-27T14:13:28Z

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 Message-Id: <20230322204344.50138-2-dmy@semihalf.com> Signed-off-by: Paolo Bonzini

KVM: update code comment in struct kvm_vcpu

2023-02-08T01:58:19Z

Commit c5b077549136 ("KVM: Convert the kvm->vcpus array to a xarray") changed kvm->vcpus array to a xarray, so update the code comment of kvm_vcpu->vcpu_idx accordingly. Signed-off-by: Wang Yong Link: https://lore.kernel.org/r/20230202081342.856687-1-yongw.kernel@gmail.com Signed-off-by: Sean Christopherson

kvm_host.h: fix spelling typo in function declaration

2023-01-24T18:04:58Z

Make parameters in function declaration consistent with those in function definition for better cscope-ability Signed-off-by: Wang Liang Reviewed-by: Sean Christopherson Link: https://lore.kernel.org/r/20220920060210.4842-1-wangliangzz@126.com Signed-off-by: Sean Christopherson

KVM: account allocation in generic version of kvm_arch_alloc_vm()

2023-01-24T18:04:57Z

Account the allocation of VMs in the generic version of kvm_arch_alloc_vm(), the VM is tied to the current task/process. Note, x86 already accounts its allocation. Signed-off-by: Alexey Dobriyan Reviewed-by: Sean Christopherson Link: https://lore.kernel.org/r/Y3aay2u2KQgiR0un@p183 [sean: reworded changelog] Signed-off-by: Sean Christopherson

KVM: Opt out of generic hardware enabling on s390 and PPC

2022-12-29T20:48:37Z

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 Acked-by: Anup Patel Message-Id: <20221130230934.1014142-50-seanjc@google.com> Signed-off-by: Paolo Bonzini

KVM: Drop kvm_arch_check_processor_compat() hook

2022-12-29T20:41:28Z

Drop kvm_arch_check_processor_compat() and its support code now that all architecture implementations are nops. Signed-off-by: Sean Christopherson Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Eric Farman # s390 Acked-by: Anup Patel Reviewed-by: Kai Huang Message-Id: <20221130230934.1014142-33-seanjc@google.com> Signed-off-by: Paolo Bonzini

KVM: Drop kvm_arch_{init,exit}() hooks

2022-12-29T20:41:23Z

Drop kvm_arch_init() and kvm_arch_exit() now that all implementations are nops. No functional change intended. Signed-off-by: Sean Christopherson Reviewed-by: Eric Farman # s390 Reviewed-by: Philippe Mathieu-Daudé Acked-by: Anup Patel Message-Id: <20221130230934.1014142-30-seanjc@google.com> Signed-off-by: Paolo Bonzini

KVM: Drop arch hardware (un)setup hooks

2022-12-29T20:40:54Z

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 Reviewed-by: Eric Farman # s390 Acked-by: Anup Patel Message-Id: <20221130230934.1014142-10-seanjc@google.com> Signed-off-by: Paolo Bonzini

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2022-12-15T19:12:21Z

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 ...