The KVM introspection subsystem provides a facility for applications
running on the host or in a separate VM, to control the execution of
other VMs (pause, resume, shutdown), query the state of the vCPUs (GPRs,
MSRs etc.), alter the page access bits in the shadow page tables (only
for the hardware backed ones, eg. Intel's EPT) and receive notifications
when events of interest have taken place (shadow page table level faults,
key MSR writes, hypercalls etc.). Some notifications can be responded
to with an action (like preventing an MSR from being written), others
are mere informative (like breakpoint events which can be used for
execution tracing). With few exceptions, all events are optional. An
application using this subsystem will explicitly register for them.
The use case that gave way for the creation of this subsystem is to
monitor the guest OS and as such the ABI/API is highly influenced by how
the guest software (kernel, applications) sees the world. For example,
some events provide information specific for the host CPU architecture
(eg. MSR_IA32_SYSENTER_EIP) merely because its leveraged by guest software
to implement a critical feature (fast system calls).
At the moment, the target audience for KVMI are security software authors
that wish to perform forensics on newly discovered threats (exploits)
or to implement another layer of security like preventing a large set
of kernel rootkits simply by "locking" the kernel image in the shadow
page tables (ie. enforce .text r-x, .rodata rw- etc.). It's the latter
case that made KVMI a separate subsystem, even though many of these
features are available in the device manager. The ability to build a
security application that does not interfere (in terms of performance)
with the guest software asks for a specialized interface that is designed
for minimum overhead.
This patch series is based on kvm/next,
commit dc924b062488 ("KVM: SVM: check CR4 changes against vcpu->arch").
The previous version (v9) can be read here:
https://lore.kernel.org/kvm/20200721210922.7646-1-alazar@xxxxxxxxxxxxxxx/
Patches 1-31: make preparatory changes
Patches 32-79: add basic introspection capabilities
Patch 80: support introspection tools that write-protect guest page tables
Patch 81: notify the introspection tool even on emulation failures
(when the read/write callbacks used by the emulator,
kvm_page_preread/kvm_page_prewrite, are not invoked)
Changes since v9:
- rebase on 5.10 from 5.8
- complete the split of x86 and arch-independent code
- split the VM and vCPU events
- clean up the interface headers (VM vs vCPU messages/events)
- clean up the tests
- add a new exit code (for the CRASH action) instead of killing
the vCPU threads [Christoph]
- other small changes (code refactoring, message validation, etc.).
Adalbert Lazăr (24):
KVM: UAPI: add error codes used by the VM introspection code
KVM: add kvm_vcpu_kick_and_wait()
KVM: doc: fix the hypercalls numbering
KVM: x86: add kvm_x86_ops.control_cr3_intercept()
KVM: x86: add kvm_x86_ops.desc_ctrl_supported()
KVM: x86: add kvm_x86_ops.control_desc_intercept()
KVM: x86: export kvm_vcpu_ioctl_x86_set_xsave()
KVM: introspection: add hook/unhook ioctls
KVM: introspection: add permission access ioctls
KVM: introspection: add the read/dispatch message function
KVM: introspection: add KVMI_GET_VERSION
KVM: introspection: add KVMI_VM_CHECK_COMMAND and KVMI_VM_CHECK_EVENT
KVM: introspection: add KVM_INTROSPECTION_PREUNHOOK
KVM: introspection: add KVMI_VM_EVENT_UNHOOK
KVM: introspection: add KVMI_VM_CONTROL_EVENTS
KVM: introspection: add a jobs list to every introspected vCPU
KVM: introspection: add KVMI_VM_PAUSE_VCPU
KVM: introspection: add support for vCPU events
KVM: introspection: add KVMI_VCPU_EVENT_PAUSE
KVM: introspection: add KVMI_VM_CONTROL_CLEANUP
KVM: introspection: add KVMI_VCPU_GET_XCR
KVM: introspection: add KVMI_VCPU_SET_XSAVE
KVM: introspection: extend KVMI_GET_VERSION with struct kvmi_features
KVM: introspection: add KVMI_VCPU_TRANSLATE_GVA
Marian Rotariu (1):
KVM: introspection: add KVMI_VCPU_GET_CPUID
Mihai Donțu (33):
KVM: x86: add kvm_arch_vcpu_get_regs() and kvm_arch_vcpu_get_sregs()
KVM: x86: avoid injecting #PF when emulate the VMCALL instruction
KVM: x86: add kvm_x86_ops.control_msr_intercept()
KVM: x86: vmx: use a symbolic constant when checking the exit
qualifications
KVM: x86: save the error code during EPT/NPF exits handling
KVM: x86: add kvm_x86_ops.fault_gla()
KVM: x86: extend kvm_mmu_gva_to_gpa_system() with the 'access'
parameter
KVM: x86: page track: provide all callbacks with the guest virtual
address
KVM: x86: page track: add track_create_slot() callback
KVM: x86: page_track: add support for preread, prewrite and preexec
KVM: x86: wire in the preread/prewrite/preexec page trackers
KVM: introduce VM introspection
KVM: introspection: add KVMI_VM_GET_INFO
KVM: introspection: add KVMI_VM_READ_PHYSICAL/KVMI_VM_WRITE_PHYSICAL
KVM: introspection: handle vCPU introspection requests
KVM: introspection: handle vCPU commands
KVM: introspection: add KVMI_VCPU_GET_INFO
KVM: introspection: add the crash action handling on the event reply
KVM: introspection: add KVMI_VCPU_CONTROL_EVENTS
KVM: introspection: add KVMI_VCPU_GET_REGISTERS
KVM: introspection: add KVMI_VCPU_SET_REGISTERS
KVM: introspection: add KVMI_VCPU_EVENT_HYPERCALL
KVM: introspection: add KVMI_VCPU_EVENT_BREAKPOINT
KVM: introspection: add KVMI_VCPU_CONTROL_CR and KVMI_VCPU_EVENT_CR
KVM: introspection: add KVMI_VCPU_INJECT_EXCEPTION +
KVMI_VCPU_EVENT_TRAP
KVM: introspection: add KVMI_VCPU_EVENT_XSETBV
KVM: introspection: add KVMI_VCPU_GET_XSAVE
KVM: introspection: add KVMI_VCPU_GET_MTRR_TYPE
KVM: introspection: add KVMI_VCPU_CONTROL_MSR and KVMI_VCPU_EVENT_MSR
KVM: introspection: add KVMI_VM_SET_PAGE_ACCESS
KVM: introspection: add KVMI_VCPU_EVENT_PF
KVM: introspection: emulate a guest page table walk on SPT violations
due to A/D bit updates
KVM: x86: call the page tracking code on emulation failure
Mircea Cîrjaliu (2):
KVM: x86: disable gpa_available optimization for fetch and page-walk
SPT violations
KVM: introspection: add vCPU related data
Nicușor Cîțu (19):
KVM: x86: add kvm_arch_vcpu_set_regs()
KVM: x86: add kvm_x86_ops.bp_intercepted()
KVM: x86: add kvm_x86_ops.cr3_write_intercepted()
KVM: svm: add support for descriptor-table VM-exits
KVM: x86: add kvm_x86_ops.desc_intercepted()
KVM: x86: add kvm_x86_ops.msr_write_intercepted()
KVM: x86: svm: use the vmx convention to control the MSR interception
KVM: x86: add kvm_x86_ops.control_singlestep()
KVM: x86: export kvm_arch_vcpu_set_guest_debug()
KVM: x86: export kvm_inject_pending_exception()
KVM: x86: export kvm_vcpu_ioctl_x86_get_xsave()
KVM: introspection: add cleanup support for vCPUs
KVM: introspection: restore the state of #BP interception on unhook
KVM: introspection: restore the state of CR3 interception on unhook
KVM: introspection: add KVMI_VCPU_EVENT_DESCRIPTOR
KVM: introspection: restore the state of descriptor-table register
interception on unhook
KVM: introspection: restore the state of MSR interception on unhook
KVM: introspection: add KVMI_VCPU_CONTROL_SINGLESTEP
KVM: introspection: add KVMI_VCPU_EVENT_SINGLESTEP
Ștefan Șicleru (2):
KVM: add kvm_get_max_gfn()
KVM: introspection: add KVMI_VM_GET_MAX_GFN
Documentation/virt/kvm/api.rst | 159 ++
Documentation/virt/kvm/hypercalls.rst | 39 +-
Documentation/virt/kvm/kvmi.rst | 1573 +++++++++++++
arch/x86/include/asm/kvm_host.h | 41 +-
arch/x86/include/asm/kvm_page_track.h | 71 +-
arch/x86/include/asm/kvmi_host.h | 110 +
arch/x86/include/asm/vmx.h | 2 +
arch/x86/include/uapi/asm/kvmi.h | 167 ++
arch/x86/kvm/Kconfig | 9 +
arch/x86/kvm/Makefile | 2 +
arch/x86/kvm/emulate.c | 4 +
arch/x86/kvm/kvm_emulate.h | 1 +
arch/x86/kvm/kvmi.c | 1131 ++++++++++
arch/x86/kvm/kvmi.h | 24 +
arch/x86/kvm/kvmi_msg.c | 457 ++++
arch/x86/kvm/mmu/mmu.c | 140 +-
arch/x86/kvm/mmu/mmu_internal.h | 4 +
arch/x86/kvm/mmu/page_track.c | 146 +-
arch/x86/kvm/mmu/spte.c | 17 +
arch/x86/kvm/svm/svm.c | 288 ++-
arch/x86/kvm/svm/svm.h | 7 +
arch/x86/kvm/vmx/capabilities.h | 7 +-
arch/x86/kvm/vmx/vmx.c | 168 +-
arch/x86/kvm/vmx/vmx.h | 4 -
arch/x86/kvm/x86.c | 305 ++-
drivers/gpu/drm/i915/gvt/kvmgt.c | 2 +-
include/linux/kvm_host.h | 20 +
include/linux/kvmi_host.h | 110 +
include/uapi/linux/kvm.h | 20 +
include/uapi/linux/kvm_para.h | 5 +
include/uapi/linux/kvmi.h | 245 ++
tools/testing/selftests/kvm/Makefile | 1 +
.../testing/selftests/kvm/x86_64/kvmi_test.c | 2005 +++++++++++++++++
virt/kvm/introspection/kvmi.c | 1263 +++++++++++
virt/kvm/introspection/kvmi_int.h | 129 ++
virt/kvm/introspection/kvmi_msg.c | 910 ++++++++
virt/kvm/kvm_main.c | 95 +
37 files changed, 9519 insertions(+), 162 deletions(-)
create mode 100644 Documentation/virt/kvm/kvmi.rst
create mode 100644 arch/x86/include/asm/kvmi_host.h
create mode 100644 arch/x86/include/uapi/asm/kvmi.h
create mode 100644 arch/x86/kvm/kvmi.c
create mode 100644 arch/x86/kvm/kvmi.h
create mode 100644 arch/x86/kvm/kvmi_msg.c
create mode 100644 include/linux/kvmi_host.h
create mode 100644 include/uapi/linux/kvmi.h
create mode 100644 tools/testing/selftests/kvm/x86_64/kvmi_test.c
create mode 100644 virt/kvm/introspection/kvmi.c
create mode 100644 virt/kvm/introspection/kvmi_int.h
create mode 100644 virt/kvm/introspection/kvmi_msg.c
base-commit: dc924b062488a0376aae41d3e0a27dc99f852a5e
CC: Edwin Zhai <edwin.zhai@xxxxxxxxx>
CC: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
CC: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
CC: Mathieu Tarral <mathieu.tarral@xxxxxxxxxxxxxx>
CC: Patrick Colp <patrick.colp@xxxxxxxxxx>
CC: Samuel Laurén <samuel.lauren@xxxxxx>
CC: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
CC: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>
CC: Weijiang Yang <weijiang.yang@xxxxxxxxx>
CC: Yu C Zhang <yu.c.zhang@xxxxxxxxx>
CC: Sean Christopherson <seanjc@xxxxxxxxxx>
CC: Joerg Roedel <joro@xxxxxxxxxx>
CC: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
CC: Wanpeng Li <wanpengli@xxxxxxxxxxx>
CC: Jim Mattson <jmattson@xxxxxxxxxx>
