kvm: nVMX: Remove unnecessary sync_roots from handle_invept

When L0 is executing handle_invept(), the TDP MMU is active. Emulating
an L1 INVEPT does require synchronizing the appropriate shadow EPT
root(s), but a call to kvm_mmu_sync_roots in this context won't do
that. Similarly, the hardware TLB and paging-structure-cache entries
associated with the appropriate shadow EPT root(s) must be flushed,
but requesting a TLB_FLUSH from this context won't do that either.

How did this ever work? KVM always does a sync_roots and TLB flush (in
the correct context) when transitioning from L1 to L2. That isn't the
best choice for nested VM performance, but it effectively papers over
the mistakes here.

Remove the unnecessary operations and leave a comment to try to do
better in the future.

Reported-by: Junaid Shahid <[email protected]>
Fixes: bfd0a56b90005f ("nEPT: Nested INVEPT")
Cc: Xiao Guangrong <[email protected]>
Cc: Nadav Har'El <[email protected]>
Cc: Jun Nakajima <[email protected]>
Cc: Xinhao Xu <[email protected]>
Cc: Yang Zhang <[email protected]>
Cc: Gleb Natapov <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Reviewed-by Peter Shier <[email protected]>
Reviewed-by: Junaid Shahid <[email protected]>
Signed-off-by: Jim Mattson <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

0 files changed, 0 insertions, 0 deletions