[PATCH v6 0/2] Enable notify VM exit

[Chenyi Qiang <chenyi.qiang@intel.com>]

Notify VM exit is introduced to mitigate the potential DOS attach from
malicious VM. This series is the userspace part to enable this feature
through a new KVM capability KVM_CAP_X86_NOTIFY_VMEXIT. The detailed
info can be seen in Patch 3.

The corresponding KVM support can be found in linux 6.0-rc1:
(2f4073e08f4c KVM: VMX: Enable Notify VM exit)

This patch set depends on some definition which can be updated from
scripts/update-linux-headers.sh. A separate patch set is sent out at
https://lists.gnu.org/archive/html/qemu-devel/2022-09/msg02102.html

---
Change logs:
v5 -> v6
- Add some info related to the valid range of notify_window in patch 2. (Peter Xu)
- Add the doc in qemu-options.hx. (Peter Xu)
- v5: https://lore.kernel.org/qemu-devel/20220817020845.21855-1-chenyi.qiang@intel.com/

v4 -> v5
- Remove the assert check to avoid the nop in NDEBUG case. (Yuan)
- v4: https://lore.kernel.org/qemu-devel/20220524140302.23272-1-chenyi.qiang@intel.com/

v3 -> v4
- Add a new KVM cap KVM_CAP_TRIPLE_FAULT_EVENT to guard the extension of triple fault
  event save&restore.
- v3: https://lore.kernel.org/qemu-devel/20220421074028.18196-1-chenyi.qiang@intel.com/

v2 -> v3
- Extend the argument to include both the notify window and some flags
  when enabling KVM_CAP_X86_BUS_LOCK_EXIT CAP.
- Change to use KVM_VCPUEVENTS_VALID_TRIPLE_FAULT in flags field and add
  pending_triple_fault field in struct kvm_vcpu_events.
- v2: https://lore.kernel.org/qemu-devel/20220318082934.25030-1-chenyi.qiang@intel.com/

v1 -> v2
- Add some commit message to explain why we disable Notify VM exit by default.
- Rename KVM_VCPUEVENT_SHUTDOWN to KVM_VCPUEVENT_TRIPLE_FAULT.
- Do the corresponding change to use the KVM_VCPUEVENTS_TRIPLE_FAULT
  to save/restore the triple fault event to avoid lose some synthesized
  triple fault from KVM.
- v1: https://lore.kernel.org/qemu-devel/20220310090205.10645-1-chenyi.qiang@intel.com/

---

Chenyi Qiang (2):
  i386: kvm: extend kvm_{get, put}_vcpu_events to support pending triple
    fault
  i386: Add notify VM exit support

 hw/i386/x86.c         | 45 ++++++++++++++++++++++++++++++++++++++++
 include/hw/i386/x86.h |  5 +++++
 qemu-options.hx       | 10 ++++++++-
 target/i386/cpu.c     |  1 +
 target/i386/cpu.h     |  1 +
 target/i386/kvm/kvm.c | 48 +++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 109 insertions(+), 1 deletion(-)

-- 
2.17.1