Re: 2.6.27.5 guest boot failure using in-kernel PIT

[Sheng Yang <sheng@linux.intel.com>]

On Friday 21 November 2008 06:05:17 Eduardo Habkost wrote:
> On Thu, Nov 20, 2008 at 12:22:53PM -0200, Eduardo Habkost wrote:
> > Hi,
> >
> > When using a kvm.git kernel as host, I am getting guest boot failures
> > when booting Fedora Rawhide kernel (2.6.27.5-117.fc10.x86_64). Guest
> > stops booting at:
> >
> > ENABLING IO-APIC IRQs
> > ..TIMER: vector=0x30 apic1=0 pin1=0 apic2=-1 pin2=-1
> > ..MP-BIOS bug: 8254 timer not connected to IO-APIC
> > ...trying to set up timer (IRQ0) through the 8259A ...
> > ..... (found apic 0 pin 0) ...
> > ....... failed.
> > ...trying to set up timer as Virtual Wire IRQ...
> > ..... failed.
> > ...trying to set up timer as ExtINT IRQ...
>
> I've just found out this problem happens because the guest has HZ=1000
> and the host had HZ=250 and no CONFIG_HIGH_RES_TIMERS.
>
> With this setup, the host is not managing to inject enough timer
> interrupts during the mdelay() loop on timer_irq_works().

So, do we need to depend on CONFIG_HIGH_RES_TIMERS? I think most modern 
machine should have this.

-- 
regards
Yang, Sheng