On 2011-08-04 10:01, Gleb Natapov wrote: > On Wed, Aug 03, 2011 at 06:25:07PM +0200, Vasilis Liaskovitis wrote: >> On Wed, Aug 03, 2011 at 12:42:11PM +0200, Jan Kiszka wrote: >>>>> Why can't Seabios read to true number online CPUs from the PIIX4 device? >>>>> The information is there already, no need for addition PV here. >>>>> >>>> Where is it in PIIX4 device? >>> >>> PROC registers (or however they are called). >> >> In qemu-kvm, the cpus_sts bitmap array in PIIX4PMState/ACPIGPE has the true >> number of online CPUS. This is accessed from the DSDT hotplug method in Seabios >> as "OperationRegion SystemIO" with address 0xaf00. Is this i/o address in the >> piix4 spec? How can it be accessed from the rest of SeaBIOS? It seems to reside >> in ACPI_PM space. >> > 0xaf00 is not part of PIIX4. PIIX4 supports nor cpu host plug > neither pci hot plug. I haven't found any PROC register in PIIX4 spec > so far. So it is some "board" extension that is declared to BIOS/OS via ACPI? In any case, the channel we need to read the number of online CPUs already exists. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- 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
