[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] trap/interrupt gate for hypercall
Please see comment question. -----Original Message----- From: Keir Fraser [mailto:Keir.Fraser@xxxxxxxxxxxx] Sent: 2007年5月16日 14:51 To: Tian, Kevin; Keir Fraser; xen-devel@xxxxxxxxxxxxxxxxxxx Cc: Liu, Jinsong Subject: Re: [Xen-devel] trap/interrupt gate for hypercall On 16/5/07 04:17, "Tian, Kevin" <kevin.tian@xxxxxxxxx> wrote: > I saw one necessity by always using interrupt gate type, that > restore_all_xen can be simplified without segment registers restore. > Or else at least ds/es need be restored for restore_all_xen if interrupt > happens at entrance of hypercall (if by trap gate type). But I'm weak > knowledge about the reason you list. What's the ability that hypercall > handler can do while interrupt handler can't when reload of a > problematic segment register? Anyway interrupt can also raise from > guest context and interrupt handle also needs to tackle fault of > reloading. Could you kindly give an example? :-) Enter Xen on hypercall, immediately take an interrupt, on return from interrupt %es faults on reload. How do we propagate this bad segment --> the problem is when return from interrupt how %es faults on reload except interrupt handler purposely modify kernel stack? --> example? Jinsong register value to the guest via the failsafe callback handler from this context? The bad %es is not yet saved on the outer context's stack frame. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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