[Qemu-devel] [PATCH v5 0/1] i386/kvm: TSC page clocksource for Hyper-V-on-KVM fixes

[Vitaly Kuznetsov]

Changes since v4:
- Rebase on top of Roman's patches.
- Drop PATCH2 as it is no longer needed (after adding explicit
  hv_frequencies).

Previously, Ladi was working on enabling TSC page clocksource for nested
Hyper-V-on-KVM workloads. He found out that if Hyper-V frequency MSRs are
exposed to L1 as well as INVTSC flag Hyper-V enables TSC page clocksource
to its guests. Qemu doesn't pass INVTSC by default as it is a migration
blocker.

I found out there's a different way to make Hyper-V like us: expose
Reenlightenment MSRs to it. KVM doesn't fully support the feature as
we're still unable to migrate nested environments but rudimentary support
we have there is enough.

Enable Hyper-V reenlightenment MSRs to make things work.

Vitaly Kuznetsov (1):
  i386/kvm: add support for Hyper-V reenlightenment MSRs

 target/i386/cpu.c          |  4 +++-
 target/i386/cpu.h          |  4 ++++
 target/i386/hyperv-proto.h |  9 ++++++++-
 target/i386/kvm.c          | 39 ++++++++++++++++++++++++++++++++++++++-
 target/i386/machine.c      | 24 ++++++++++++++++++++++++
 5 files changed, 77 insertions(+), 3 deletions(-)

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2.14.3