[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Mem_event API and MEM_EVENT_REASON_SINGLESTEP
> Not sure what the difference is between first write operation and > first write mem_event. The difference is this: a write operation will only trigger a write event for a page marked rx. So if we're in single step mode and a write happens on a page marked rwx, this will not trigger a write mem_event. >> My scenario is this: I'd like to mark _all_ of the domain's pages rw, >> then when I get a write mem_event, mark only one page rwx, allow that >> write (single stepping), then mark that one page rw again. This would > > Do you mean rx? If you mark a page rw you will not get a write mem_event for > it. Yes, I meant rx. Sorry (it's late where I'm writing from). > You could track the EIP and GFN and if you single step more than one > instruction you can mark the page RX and stop single stepping. You > will get control again on the next write. Though if there are jmp, > things could get tricky. So if I understand you correctly, simply single-stepping for only the duration of one MEM_EVENT_REASON_SINGLESTEP, which should be the write operation (ignoring the gfn/gla fields of the mem_event), should do the trick? Thanks, Razvan Cojocaru _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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