On 02/20/2013 07:37 AM, David Woodhouse wrote: > On Wed, 2013-02-20 at 16:34 +0100, Paolo Bonzini wrote: >> Il 20/02/2013 16:18, Laszlo Ersek ha scritto: >>>>> I'm beginning to wish I'd just ignored the fact that >>>>> we need a properly working "soft" reset to get back from 286 protected >>>>> mode to real mode, and wired up the damn PAM reset unconditionally. I'm >>>>> not convinced that the protected->real mode transition will work for >>>>> anyone anyway. >>> I believe currently we must be somewhere "between" soft reset & hard >>> reset. I estimate getting closer to a well-emulated hard reset is more >>> important than getting closer to a soft one. If you were to extend the >>> i440FX reset handler so that it unconditionally resets the PAMs, I'd >>> give my Rb. (Take it for what it's worth :)) >> >> It would actually make sense. The right way to do soft reset has >> nothing to do with qemu_system_reset_request(). > > I've posted that version of the patch, with a suitable comment. >
Right... the "soft reset" described above is really INIT, which isn't even a reset in modern CPUs (it couldn't be, it has to preserve caches) but more of a special interrupt. It is also used during multiprocessor init. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.