[SeaBIOS] [PATCH v4 0/5] support booting more than 255 CPUs with QEMU

[Igor Mammedov]

Changelog since:
  v3:
    * don't move CPU counting around, leave it as is and
      consolidate apic_id accounting only
    * add and use qemu_*_present_cpus_count() helpers to init/get boot
      cpus count at boot time and only qemu_get_present_cpus_count()
      at resume time
    * fix S3 wakeup stuck in resume vector
    * If cpu were hotplugged during smp_scan, report it to user
      instead of silently hanging if it came online while smp_scan()
      waits for APs
  v2:
    * rebase on top of current master /smp_scan() changes/
  v1:
    * s/count_cpu/apic_id_init/
    * merge handle_x2apic() into apic_id_init()
  RFC:
    * move out max-cpus check out of mptable_setup()
    * factor out CPU counting/apic ID detection in separate function
    * return back accidentially deleted debug message with APIC ID
    * drop unused code in smp_setup()
    
According to SDM, if CPUs have APIC ID more than 254
firmware should pass control to OS in x2APIC mode.
This series adds x2APIC bootstrap initialization.

Works fine with not yet rebased on master QEMU side of x2APIC support:
https://www.mail-archive.com/qemu-devel@nongnu.org/msg390671.html
Rebased variant probably will be sent next week.

Note:
S3 wakeup works as expected if linux guest is running with IRQ remapping enabled.
However it seems that kernel is buggy with IRQ remapping disabled as kernel
disables CPUs with APIC ID > 254 and on resume from S3 hangs somewere after
getting control from Seabios.


Igor Mammedov (4):
  paravirt: disable legacy bios tables in case of more than 255 CPUs
  error out if present cpus count changed during SMP bringup
  add helpers to read etc/boot-cpus at resume time
  support booting with more than 255 CPUs

Kevin O'Connor (1):
  smp: consolidate CPU APIC ID detection and accounting

 src/fw/paravirt.h |  3 +++
 src/x86.h         |  1 +
 src/fw/paravirt.c | 44 +++++++++++++++++++++++++++++++++++--
 src/fw/smp.c      | 65 ++++++++++++++++++++++++++++++++++++++-----------------
 4 files changed, 91 insertions(+), 22 deletions(-)

-- 
2.7.4