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  1. OpenShift Virtualization
  2. CNV-78027

[CLOSED LOOP for] Missing knob to control hv-tlbflush-direct and hv-tlbflush-extended

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    • Resolution: Unresolved
    • Icon: Critical Critical
    • CNV v4.22.0
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      Description of problem:

      hv-tlbflush-direct can be useful to optimize performance in nested virtualization cases, such as Windows VBS.
hv-tlbflush-extended can also help and is not limited to nested scenarios.

      Version-Release number of selected component (if applicable):

      At least up to 4.19.10

      How reproducible:

      We can control tlbflush, but not tlbflush-direct/extended

# oc explain vm.spec.template.spec.domain.features.hyperv | grep Object
FIELD: hyperv <Object>
  evmcs	<Object>
  frequencies	<Object>
  ipi	<Object>
  reenlightenment	<Object>
  relaxed	<Object>
  reset	<Object>
  runtime	<Object>
  spinlocks	<Object>
  synic	<Object>
  synictimer	<Object>
  tlbflush	<Object>
  vapic	<Object>
  vendorid	<Object>
  vpindex	<Object>

      https://www.qemu.org/docs/master/system/i386/hyperv.html

              sgott@redhat.com Stuart Gott
              dagur@redhat.com Daniel Gur
              Denys Shchedrivyi Denys Shchedrivyi
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                Created:
                Updated: