Re: [Qemu-devel] [PATCH] qemu: x86: report lapic version as 0x14 instead of 0x11

[Paolo Bonzini <pbonzini@redhat.com>]

Il 28/02/2014 20:14, Gabriel L. Somlo ha scritto:
> Some guests (e.g. 0S X) insist on a minimum lapic version of 0x14.
> This patch bumps the emulated lapic version to 0x14 to accomodate that.
>
> Signed-off-by: Gabriel L. Somlo <somlo@cmu.edu>
> ---
>
> Along with the TCG ioapic polarity fix, this allows me to boot OS X
> without KVM acceleration.
>
> I dug around the Intel docs and searched the Web, and there was nothing
> there to indicate any difference in functionality between lapic versions
> 0x11 and 0x14. It appears to me that lapic version is loosely correlated
> with the "generation" of the CPU it's attached to, and Apple simply decided
> to include an extra check that basically says "we don't support CPUs older
> than <foo>", where the oldest <foo> they support ships with lapics that
> were versioned to 0x14 :) For example:
>
> http://www.opensource.apple.com/source/xnu/xnu-1456.1.26/osfmk/i386/lapic.c
>
> Let me know what you think.
>
> Thanks,
>   Gabriel
>
>  hw/intc/apic.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/intc/apic.c b/hw/intc/apic.c
> index 361ae90..67365b7 100644
> --- a/hw/intc/apic.c
> +++ b/hw/intc/apic.c
> @@ -675,7 +675,7 @@ static uint32_t apic_mem_readl(void *opaque, hwaddr addr)
>          val = s->id << 24;
>          break;
>      case 0x03: /* version */
> -        val = 0x11 | ((APIC_LVT_NB - 1) << 16); /* version 0x11 */
> +        val = 0x14 | ((APIC_LVT_NB - 1) << 16); /* version 0x14 */
>          break;
>      case 0x08:
>          apic_sync_vapic(s, SYNC_FROM_VAPIC);
>

Looks good, but you have to make this a qdev property so that older 
versions keep using version 0x11.

Paolo