KVM: MIPS/Emulate: Update CP0_Compare emulation for VZ

Update emulation of guest writes to CP0_Compare for VZ. There are two
main differences compared to trap & emulate:

 - Writing to CP0_Compare in the VZ hardware guest context acks any
   pending timer, clearing CP0_Cause.TI. If we don't want an ack to take
   place we must carefully restore the TI bit if it was previously set.

 - Even with guest timer access disabled in CP0_GuestCtl0.GT, if the
   guest CP0_Count reaches the guest CP0_Compare the timer interrupt
   will assert. To prevent this we must set CP0_GTOffset to move the
   guest CP0_Count out of the way of the new guest CP0_Compare, either
   before or after depending on whether it is a forwards or backwards
   change.

Signed-off-by: James Hogan <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: "Radim Krčmář" <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: [email protected]
Cc: [email protected]

0 files changed, 0 insertions, 0 deletions