KVM: VMX: Cache IA32_DEBUGCTL in memory

MSR_IA32_DEBUGCTLMSR is zeroed on VMEXIT, so it is saved/restored each
time during world switch.  This patch caches the host IA32_DEBUGCTL MSR
and saves/restores the host IA32_DEBUGCTL msr when guest/host switches
to avoid to save/restore each time during world switch.  This saves
about 100 clock cycles per vmexit.

Suggested-by: Jim Mattson <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Radim Krčmář <[email protected]>
Cc: Jim Mattson <[email protected]>
Signed-off-by: Wanpeng Li <[email protected]>
Reviewed-by: Jim Mattson <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Signed-off-by: Radim Krčmář <[email protected]>

0 files changed, 0 insertions, 0 deletions