[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] Hypercalls in Intel-VT
> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx > [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Ashish Bijlani > Sent: 2007年10月26日 7:44 > To: xen-devel@xxxxxxxxxxxxxxxxxxx > Subject: Re: [Xen-devel] Hypercalls in Intel-VT > if I push xen's some addr (cs & eip) on the target guest os krnl stack when > an interrupt occurs, would the guest os krnl return to xen > immediately upon executing iret (as iret pops cs, eip from the krnl stack)? > or would it make a vmexit coz of some illegal addr access I assume you're only talking about Intel VMX guest. The answer is NO. For instance, a VMX guest is running in "non-root mode"; it can only use its (shadowed) page table; it can't use IRET to return to Xen that's running on "root mode". If you did that, what would happen is, i.e., a 32-bit protection-mode guest uses its own GDT -- the guest may find the GDT entry indexed by Xen's CS is invalid, so a #GP is generated in guest directly, and guest handles this (No VMexit). -- Dexuan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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