On Wed, Mar 10, 2010 at 11:12:34AM +0200, Avi Kivity wrote: > On 03/09/2010 08:09 PM, Gleb Natapov wrote: > > > >>We don't want to enter the emulator for non-string in/out. Leftover > >>test code? > >> > >No, unfortunately this is not leftover. I just don't see a way how we > >can bypass emulator and still have emulator be able to emulate in/out > >(for big real mode for instance). The problem is basically described in > >the commit message. If we have function outside of emulator that does > >in/out emulation on vcpu directly, then emulator can't use it since > >committing shadowed registers will overwrite the result of emulation. > >Having two different emulations (one outside of emulator and another in > >emulator) is also problematic since when userspace returns after IO exit > >we don't know which emulation to continue. If we want to avoid > >instruction decoding we can fill in emulation context from exit info as > >if instruction was already decoded and call emulator. > > > > Alternatively, another entry point would be fine. in/out is a fast > path (used for virtio for example). > You mean another entry point into emulator, not separate implementation for emulated in/out and intercepted one. If yes this is what I mean by "faking" decoding stage. -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
