On Thu, Jul 19, 2012 at 05:52:42PM -0300, Eduardo Habkost wrote:
Extract Local APIC IDs directly from the CPUs, and instead of check for "i < CountCPUs", check if the APIC ID was present on boot, when building ACPI tables and the MP-Table.
This keeps ACPI Processor ID == APIC ID, but allows the hardware<->Seabios interface be completely APIC-ID based, and Seabios may change the way ACPI Processor IDs are chosen in the future.
As we currently Seabios support only xAPIC and not x2APIC, the list of present-on-boot APIC IDs is a 256-bit bitmap. If one day Seabios starts to support x2APIC, the data structure used to enumerate the APIC IDs will have to be changed.
Is this SeaBIOS change dependent on a particular version of QEMU?
[...]
--- a/src/smp.c +++ b/src/smp.c @@ -36,6 +36,8 @@ wrmsr_smp(u32 index, u64 val)
u32 CountCPUs VAR16VISIBLE; u32 MaxCountCPUs VAR16VISIBLE; +// 256 bits for the found APIC IDs +u32 FoundAPICIDs[256/32] VAR16VISIBLE; extern void smp_ap_boot_code(void); ASM16( " .global smp_ap_boot_code\n" @@ -59,6 +61,12 @@ ASM16( " jmp 1b\n" "2:\n"
- // get apic ID on EBX, set bit on FoundAPICIDs
- " mov $1, %eax\n"
- " cpuid\n"
- " shrl $24, %ebx\n"
- " lock bts %ebx, FoundAPICIDs\n"
Because of the insanity that is 16bit mode, please use explicit size suffixes on assembler instructions (ie, "movl" and "btsl").
-Kevin