[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Nested events in 64bit mini-OS
Xu Zhang, le Tue 13 Nov 2012 19:49:27 -0600, a écrit : > 1. if event is disabled: doesn't hurt to mask it again; > 2. if event is enabled: we disable event, and jumps to hypercall_page to > make a hypercall iret, which eventually calls do_iret: > > In do_iret, line 309: > /* Restore upcall mask from supplied EFLAGS.IF. */ > vcpu_info(v, evtchn_upcall_mask) = !(iret_saved.rflags & > X86_EFLAGS_IF); Ah, right. Disabling events just before the jmp seems all right to me then. > Correct me if I am wrong, I think hypercall_page is mapped at runtime to > guest OS by Xen. It's not actually part of the critical section of guest OS, > at least not at compile time. Sure. I meant it'd mean a second fixup table, but who knows what code is there, it could be tampering with the stack. > Following the discussion above, we could easily avoid such fixup table > by mask out the events. Completely. Samuel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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