Re: [patch 0/2] Fix rawhide FV booting on VMX

["Daniel P. Berrange" <berrange@redhat.com>]

On Tue, May 22, 2007 at 04:38:12PM +0100, Stephen C. Tweedie wrote:
> So the fix here is to first of all extend the virtual PIC provided by
> the hypervisor, supporting a new 2-byte control sequence which lets the
> guests change the interrupt vectors _without_ fully reinitialising the
> vPIC; and secondly to have vmxassist use that sequence to reset the vPIC
> vectors appropriately whenever we transition between 16 and 32-bit mode.
> 
> This has been verified to allow rawhide installs to proceed under Xen
> FV.  

I've tested that with this patch applied, Xen 3.1.0 is able to succesfully
boot  RHEL-3, RHEL-4, RHEL-5, both i386 & x86_64  fullyvirt, and also
Mandriva CS-4 boots. SuSE 10.1 still black screens with / without this
patch. So on the whole it seems to be an improvement, with no regressions
I've found yet.

> Points for discussion:
> 
> * Do we need/want vmxassist to fail gracefully if the enhanced vPIC
> sequence is not available?
> * Is the magic sequence used here (0xff written to ICW1) genuinely
> impossible for other guests to use? (see patch 1/2 to follow.)

Dan.
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