Jeremy Fitzhardinge a789ed5fb6 xen: cache cr0 value to avoid trap'n'emulate for read_cr0
stts() is implemented in terms of read_cr0/write_cr0 to update the
state of the TS bit.  This happens during context switch, and so
is fairly performance critical.  Rather than falling back to
a trap-and-emulate native read_cr0, implement our own by caching
the last-written value from write_cr0 (the TS bit is the only one
we really care about).

Impact: optimise Xen context switches
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-05-08 15:55:24 -07:00
..
2009-05-02 15:36:10 -07:00
2009-05-01 10:54:00 +02:00