Re: Re: windows7 installer lockup with viridian=1

[Tim Deegan <Tim.Deegan@citrix.com>]

At 22:52 +0100 on 27 Apr (1240872772), Frank van der Linden wrote:
> Andrew Lyon wrote:
> > On Sun, Apr 26, 2009 at 6:02 PM, Andrew Lyon <andrew.lyon@gmail.com> wrote:
> >> Hi,
> >>
> >> I've been testing both 64 and 32 bit flavour of windows 7 on Xen since
> >> the first public beta release, a few weeks ago I upgraded to Xen
> >> unstable and added viridian=1 to all of my smp windows guests as it
> >> prevents bsod bugcheck code 101 when under heavy load, today I tried
> >> to upgrade my windows 7 hvm's to build 7077 and found that the
> >> installer/bootloader locks up if viridian=1 is set.
> >>
> >> It is not the installer that locks up as such, its the windows 7
> >> equivalent of the boot progress bar that all recent versions of
> >> windows display before the graphics drivers are loaded and the display
> >> switches to a higher resolution with the mouse active.
> 
> I can reproduce this on our Xen bits (which is 3.3.x plus some patches, 
> including the viridian code).
> 
> When I modify the viridian code to not advertise the APIC-via-MSR 
> capability, Windows 7 boots just fine. With it, it hangs at the same 
> point you describe.
> 
> I don't recall that this happened when I initially tested Windows 7, so 
> perhaps something changed in the vlapic code that triggers this issue.

Win7 changes the meaning of some of the bits in the viridian interface,
so with what we have now it ends up thinking it doesn't have to EOI any
interrupts (or something similar).  A patch is on the way soon.

Cheers,

Tim.

-- 
Tim Deegan <Tim.Deegan@citrix.com>
Principal Software Engineer, Citrix Systems (R&D) Ltd.
[Company #02300071, SL9 0DZ, UK.]