On Fri, Aug 05, 2016 at 11:46:15AM +0200, Igor Mammedov wrote:
> Currently firmware uses 1 byte at 0x5F offset in RTC CMOS
> to get number of CPUs present at boot. However 1 byte is
> not enough to handle more than 255 CPUs. So add a new
> fw_cfg file that would allow QEMU to tell it.
> For compat reasons add file only for machine types that
> support more than 255 CPUs.
>
> Signed-off-by: Igor Mammedov <[email protected]>
Do we really need this? Why differentiate between boot
cpus and others? How about reusing the hotplug
register, such that it looks just as if all CPUs
were just added by hotplug?
> ---
> hw/i386/pc.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index c2cd5bd..2b5581a 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1235,9 +1235,11 @@ void pc_machine_done(Notifier *notifier, void *data)
> PCMachineState *pcms = container_of(notifier,
> PCMachineState, machine_done);
> PCIBus *bus = pcms->bus;
> + static uint16_t boot_cpus;
>
> /* set the number of CPUs */
> - rtc_set_memory(pcms->rtc, 0x5f, pc_present_cpus_count(pcms) - 1);
> + boot_cpus = pc_present_cpus_count(pcms);
> + rtc_set_memory(pcms->rtc, 0x5f, boot_cpus - 1);
>
> if (bus) {
> int extra_hosts = 0;
> @@ -1258,8 +1260,16 @@ void pc_machine_done(Notifier *notifier, void *data)
>
> acpi_setup();
> if (pcms->fw_cfg) {
> + MachineClass *mc = MACHINE_GET_CLASS(pcms);
> +
> pc_build_smbios(pcms->fw_cfg);
> pc_build_feature_control_file(pcms);
> +
> + if (mc->max_cpus > 255) {
> + boot_cpus = cpu_to_le16(boot_cpus);
> + fw_cfg_add_file(pcms->fw_cfg, "etc/boot-cpus", &boot_cpus,
> + sizeof(boot_cpus));
> + }
> }
> }
>
> --
> 2.7.4
