8.0 still doesn't boot in Xen (kern/138863)

[Kevin]

On Nov 24, 2009, at 11:20 AM, Kevin wrote:

>
> Is it too late in the 8.0 release schedule to look at kern/138863?  
> Between 7.x and 8.0 the kernel can no longer boot under Xen due to  
> changes involving CLFLUSH. The effect is a crash very early in the  
> boot, with no workaround. (This is under Xen's fully virtualized  
> mode, not the XEN platform port underway.)
>
> This was also mentioned on the Xen mailing lists back in September (http://lists.freebsd.org/pipermail/freebsd-xen/2009-September/000310.html 
> ) but nothing has been committed to fix this yet.
>
> XenServer is getting pretty popular in some enterprise and hosting  
> environments, so having 8.0 not bootable would be a bit  
> disappointing. :)

I was just pointed to the change from a couple of days ago, adding the  
tunable "hw.clflush_disable". This looks like it might do what I need,  
so I'm building a new bootable CD to find out and update the PR.

This should probably be documented somewhere, just so someone in a  
similar situation even knows about this tunable.

-- Kevin