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Re: [Xen-devel] Re: windows bluescreen after restore

At 07:25 -0400 on 02 May (1178090752), Guy Zana wrote:
> IRQL_NOT_LESS_OR_EQUAL happens when a kernel thread with high priority tries 
> to access a virtual address which is paged to the disk (since the paging 
> mechanism in windows runs in a lower priority of the thread). Most of the 
> chances that this is around paging...
> If you can reproduce the bug and it happens any time that you do 
> save/restore, I would suggest to try to tun the guest with paging disabled 
> (System Properties -> Advanced -> Performace [Settings] -> Advanced -> 
> Virtual Memory [Change] -> Select "No paging file") and then try to do 
> save&resote.
> STOP 0x8E is KERNEL_MODE_EXCEPTION_NOT_HANDLED and could be a side effect...

Both of these stop codes are cause by the kernel taking a page fault
when it didn't expect one (at a higher TPR level than the PF handler, or
in non-paged memory).  This is probably because either CPU state
(CR3/CR4/EFER) or memory (guest pagetables) have been corrupted by the
save/restore, so the shadow code sees garbage in the guest's pagetables
and passes a pagefault to the guest.


Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>, XenSource UK Limited
Registered office c/o EC2Y 5EB, UK; company number 05334508

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