Virtual machines can exploit Intel ISA characterstics to cause functional denial of service to the VMM. This series introduces a new feature named Notify VM exit, which can help mitigate such kind of attacks. Patch 1: An extension of KVM_SET_VCPU_EVENTS ioctl to inject a synthesized shutdown event from user space. This is also a fix for other synthesized triple fault, e.g. the RSM patch or nested_vmx_abort(), which could get lost when exit to userspace to do migrate. Patch 2: A selftest about get/set triple fault event. Patch 3: Introduce struct kvm_caps to track misc global KVM cap/setting. Patch 4: The main patch to enable Notify VM exit. --- Change logs: v6 -> v7 - Introduce a new cap KVM_CAP_TRIPLE_FAULT_EVENT to guard the extension of get/set triple fault event. (Sean) - Add patch 3 from Sean to integrate misc kvm cap/settings. (Sean) - Add the kvm lock around the notify_window and flag setting. (Sean) - v6: https://lore.kernel.org/lkml/20220421072958.16375-1-chenyi.qiang@xxxxxxxxx/ v5 -> v6 - Do some changes in document. - Add a selftest about get/set triple fault event. (Sean) - extend the argument to include both the notify window and some flags when enabling KVM_CAP_X86_BUS_LOCK_EXIT CAP. (Sean) - Change to use KVM_VCPUEVENT_VALID_TRIPE_FAULT in flags field and add pending_triple_fault field in struct kvm_vcpu_events, which allows userspace to make/clear triple fault request. (Sean) - Add a flag in kvm_x86_ops to avoid the kvm_has_notify_vmexit global varialbe and its export.(Sean) - v5: https://lore.kernel.org/lkml/20220318074955.22428-1-chenyi.qiang@xxxxxxxxx/ v4 -> v5 - rename KVM_VCPUEVENTS_SHUTDOWN to KVM_VCPUEVENTS_TRIPLE_FAULT. Make it bidirection and add it to get_vcpu_events. (Sean) - v4: https://lore.kernel.org/all/20220310084001.10235-1-chenyi.qiang@xxxxxxxxx/ v3 -> v4 - Change this feature to per-VM scope. (Jim) - Once VM_CONTEXT_INVALID set in exit_qualification, exit to user space notify this fatal case, especially the notify VM exit happens in L2. (Jim) - extend KVM_SET_VCPU_EVENTS to allow user space to inject a shutdown event. (Jim) - A minor code changes. - Add document for the new KVM capability. - v3: https://lore.kernel.org/lkml/20220223062412.22334-1-chenyi.qiang@xxxxxxxxx/ v2 -> v3 - add a vcpu state notify_window_exits to record the number of occurence as well as a pr_warn output. (Sean) - Add the handling in nested VM to prevent L1 bypassing the restriction through launching a L2. (Sean) - Only kill L2 when L2 VM is context invalid, synthesize a EXIT_REASON_TRIPLE_FAULT to L1 (Sean) - To ease the current implementation, make module parameter notify_window read-only. (Sean) - Disable notify window exit by default. - v2: https://lore.kernel.org/lkml/20210525051204.1480610-1-tao3.xu@xxxxxxxxx/ v1 -> v2 - Default set notify window to 0, less than 0 to disable. - Add more description in commit message. --- Chenyi Qiang (2): KVM: x86: Extend KVM_{G,S}ET_VCPU_EVENTS to support pending triple fault KVM: selftests: Add a test to get/set triple fault event Sean Christopherson (1): KVM: x86: Introduce "struct kvm_caps" to track misc caps/settings Tao Xu (1): KVM: VMX: Enable Notify VM exit Documentation/virt/kvm/api.rst | 57 +++++++ arch/x86/include/asm/kvm_host.h | 24 ++- arch/x86/include/asm/vmx.h | 7 + arch/x86/include/asm/vmxfeatures.h | 1 + arch/x86/include/uapi/asm/kvm.h | 6 +- arch/x86/include/uapi/asm/vmx.h | 4 +- arch/x86/kvm/cpuid.c | 8 +- arch/x86/kvm/debugfs.c | 4 +- arch/x86/kvm/lapic.c | 2 +- arch/x86/kvm/svm/nested.c | 4 +- arch/x86/kvm/svm/svm.c | 13 +- arch/x86/kvm/vmx/capabilities.h | 6 + arch/x86/kvm/vmx/nested.c | 12 +- arch/x86/kvm/vmx/vmx.c | 62 ++++++-- arch/x86/kvm/x86.c | 140 +++++++++++------- arch/x86/kvm/x86.h | 33 ++++- include/uapi/linux/kvm.h | 11 ++ tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../kvm/x86_64/triple_fault_event_test.c | 101 +++++++++++++ 20 files changed, 390 insertions(+), 107 deletions(-) create mode 100644 tools/testing/selftests/kvm/x86_64/triple_fault_event_test.c -- 2.17.1
