KVM: Lazify fpu activation and deactivation

Defer fpu deactivation as much as possible - if the guest fpu is loaded, keep
it loaded until the next heavyweight exit (where we are forced to unload it).
This reduces unnecessary exits.

We also defer fpu activation on clts; while clts signals the intent to use the
fpu, we can't be sure the guest will actually use it.

Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Avi Kivity 2009-12-30 12:40:26 +02:00 • committed by Marcelo Tosatti
commit 02daab21d9
5 changed files with 38 additions and 31 deletions