On 2011-05-19 15:52, Anthony Liguori wrote: > On 05/19/2011 03:30 AM, Jan Kiszka wrote: >> On 2011-05-19 10:26, Gleb Natapov wrote: >>> On Wed, May 18, 2011 at 09:27:55PM +0200, Jan Kiszka wrote: >>>>> if an I/O is to the APIC page, >>>>> it's handled by the APIC >>>> >>>> That's not that simple. We need to tell apart: >>>> - if a cpu issued the request, and which one => forward to APIC >>> And cpu mode may affect where access is forwarded to. If cpu is in SMM >>> mode access to frame buffer may be forwarded to a memory (depends on >>> chipset configuration). >> >> So we have a second use case for CPU-local I/O regions? >> >> I wonder if only a single CPU can enter SMM or if all have to. > > For the i440fx, it's a chipset register (not a per-CPU register).
There are two sources: the chipset register and the mode of the first CPU. Both things were apparently incorrectly merged into the minimalistic i440fx model. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux
