KVM/arm64 updates for 6.4 - 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.
* kvm-arm64/smccc-filtering: : . : SMCCC call filtering and forwarding to userspace, courtesy of : Oliver Upton. From the cover letter: : : "The Arm SMCCC is rather prescriptive in regards to the allocation of : SMCCC function ID ranges. Many of the hypercall ranges have an : associated specification from Arm (FF-A, PSCI, SDEI, etc.) with some : room for vendor-specific implementations. : : The ever-expanding SMCCC surface leaves a lot of work within KVM for : providing new features. Furthermore, KVM implements its own : vendor-specific ABI, with little room for other implementations (like : Hyper-V, for example). Rather than cramming it all into the kernel we : should provide a way for userspace to handle hypercalls." : . KVM: selftests: Fix spelling mistake "KVM_HYPERCAL_EXIT_SMC" -> "KVM_HYPERCALL_EXIT_SMC" KVM: arm64: Test that SMC64 arch calls are reserved KVM: arm64: Prevent userspace from handling SMC64 arch range KVM: arm64: Expose SMC/HVC width to userspace KVM: selftests: Add test for SMCCC filter KVM: selftests: Add a helper for SMCCC calls with SMC instruction KVM: arm64: Let errors from SMCCC emulation to reach userspace KVM: arm64: Return NOT_SUPPORTED to guest for unknown PSCI version KVM: arm64: Introduce support for userspace SMCCC filtering KVM: arm64: Add support for KVM_EXIT_HYPERCALL KVM: arm64: Use a maple tree to represent the SMCCC filter KVM: arm64: Refactor hvc filtering to support different actions KVM: arm64: Start handling SMCs from EL1 KVM: arm64: Rename SMC/HVC call handler to reflect reality KVM: arm64: Add vm fd device attribute accessors KVM: arm64: Add a helper to check if a VM has ran once KVM: x86: Redefine 'longmode' as a flag for KVM_EXIT_HYPERCALL Signed-off-by: Marc Zyngier <maz@kernel.org>
The 'longmode' field is a bit annoying as it blows an entire __u32 to represent a boolean value. Since other architectures are looking to add support for KVM_EXIT_HYPERCALL, now is probably a good time to clean it up. Redefine the field (and the remaining padding) as a set of flags. Preserve the existing ABI by using bit 0 to indicate if the guest was in long mode and requiring that the remaining 31 bits must be zero. Cc: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230404154050.2270077-2-oliver.upton@linux.dev
And this is the moment you have all been waiting for: setting the counter offset from userspace. We expose a brand new capability that reports the ability to set the offset for both the virtual and physical sides. In keeping with the architecture, the offset is expressed as a delta that is substracted from the physical counter value. Once this new API is used, there is no going back, and the counters cannot be written to to set the offsets implicitly (the writes are instead ignored). Reviewed-by: Colton Lewis <coltonlewis@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230330174800.2677007-8-maz@kernel.org
The KVM_GET_NR_MMU_PAGES ioctl is quite questionable on 64-bit hosts since it fails to return the full 64 bits of the value that can be set with the corresponding KVM_SET_NR_MMU_PAGES call. Its "long" return value is truncated into an "int" in the kvm_arch_vm_ioctl() function. Since this ioctl also never has been used by userspace applications (QEMU, Google's internal VMM, kvmtool and CrosVM have been checked), it's likely the best if we remove this badly designed ioctl before anybody really tries to use it. Signed-off-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20230208140105.655814-4-thuth@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* Two more V!=R patches * The last part of the cmpxchg patches * A few fixes
User space can use the MEM_OP ioctl to make storage key checked reads and writes to the guest, however, it has no way of performing atomic, key checked, accesses to the guest. Extend the MEM_OP ioctl in order to allow for this, by adding a cmpxchg op. For now, support this op for absolute accesses only. This op can be used, for example, to set the device-state-change indicator and the adapter-local-summary indicator atomically. Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> Link: https://lore.kernel.org/r/20230206164602.138068-13-scgl@linux.ibm.com Message-Id: <20230206164602.138068-13-scgl@linux.ibm.com> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
When building a list of filter events, it can sometimes be a challenge to fit all the events needed to adequately restrict the guest into the limited space available in the pmu event filter. This stems from the fact that the pmu event filter requires each event (i.e. event select + unit mask) be listed, when the intention might be to restrict the event select all together, regardless of it's unit mask. Instead of increasing the number of filter events in the pmu event filter, add a new encoding that is able to do a more generalized match on the unit mask. Introduce masked events as another encoding the pmu event filter understands. Masked events has the fields: mask, match, and exclude. When filtering based on these events, the mask is applied to the guest's unit mask to see if it matches the match value (i.e. umask & mask == match). The exclude bit can then be used to exclude events from that match. E.g. for a given event select, if it's easier to say which unit mask values shouldn't be filtered, a masked event can be set up to match all possible unit mask values, then another masked event can be set up to match the unit mask values that shouldn't be filtered. Userspace can query to see if this feature exists by looking for the capability, KVM_CAP_PMU_EVENT_MASKED_EVENTS. This feature is enabled by setting the flags field in the pmu event filter to KVM_PMU_EVENT_FLAG_MASKED_EVENTS. Events can be encoded by using KVM_PMU_ENCODE_MASKED_ENTRY(). It is an error to have a bit set outside the valid bits for a masked event, and calls to KVM_SET_PMU_EVENT_FILTER will return -EINVAL in such cases, including the high bits of the event select (35:32) if called on Intel. With these updates the filter matching code has been updated to match on a common event. Masked events were flexible enough to handle both event types, so they were used as the common event. This changes how guest events get filtered because regardless of the type of event used in the uAPI, they will be converted to masked events. Because of this there could be a slight performance hit because instead of matching the filter event with a lookup on event select + unit mask, it does a lookup on event select then walks the unit masks to find the match. This shouldn't be a big problem because I would expect the set of common event selects to be small, and if they aren't the set can likely be reduced by using masked events to generalize the unit mask. Using one type of event when filtering guest events allows for a common code path to be used. Signed-off-by: Aaron Lewis <aaronlewis@google.com> Link: https://lore.kernel.org/r/20221220161236.555143-5-aaronlewis@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
These are (uint64_t)-1 magic values are a userspace ABI, allowing the shared info pages and other enlightenments to be disabled. This isn't a Xen ABI because Xen doesn't let the guest turn these off except with the full SHUTDOWN_soft_reset mechanism. Under KVM, the userspace VMM is expected to handle soft reset, and tear down the kernel parts of the enlightenments accordingly. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20221226120320.1125390-5-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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