[v2,0/4] Add support for capturing the highest observable L2 TSC

Message

Aaron Lewis Nov. 5, 2019, 7:19 p.m. UTC

The L1 hypervisor may include the IA32_TIME_STAMP_COUNTER MSR in the
vmcs12 MSR VM-exit MSR-store area as a way of determining the highest
TSC value that might have been observed by L2 prior to VM-exit. The
current implementation does not capture a very tight bound on this
value.  To tighten the bound, add the IA32_TIME_STAMP_COUNTER MSR to the
vmcs02 VM-exit MSR-store area whenever it appears in the vmcs12 VM-exit
MSR-store area.  When L0 processes the vmcs12 VM-exit MSR-store area
during the emulation of an L2->L1 VM-exit, special-case the
IA32_TIME_STAMP_COUNTER MSR, using the value stored in the vmcs02
VM-exit MSR-store area to derive the value to be stored in the vmcs12
VM-exit MSR-store area.

v1 -> v2:
 - Rename function nested_vmx_get_msr_value() to
   nested_vmx_get_vmexit_msr_value().
 - Remove unneeded tag 'Change-Id' from commit messages.

Aaron Lewis (4):
  kvm: nested: Introduce read_and_check_msr_entry()
  kvm: vmx: Rename NR_AUTOLOAD_MSRS to NR_MSR_ENTRIES
  kvm: vmx: Rename function find_msr() to vmx_find_msr_index()
  KVM: nVMX: Add support for capturing highest observable L2 TSC

 arch/x86/kvm/vmx/nested.c | 127 ++++++++++++++++++++++++++++++++------
 arch/x86/kvm/vmx/vmx.c    |  14 ++---
 arch/x86/kvm/vmx/vmx.h    |   9 ++-
 3 files changed, 122 insertions(+), 28 deletions(-)

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2.24.0.rc1.363.gb1bccd3e3d-goog