On 21/11/16 13:38, Boris Ostrovsky wrote: > On 11/21/2016 05:40 AM, Andrew Cooper wrote: >> On 16/11/16 10:51, Andrew Cooper wrote: >>> vmcb->nextrip can legitimately be less than vmcb->rip when execution wraps >>> back around to 0. Instead, complain if the reported length is greater than >>> 15 >>> and use x86_decode_insn() as a fallback. > Why do we need to complain? In the case that you are addressing by this > patch wouldn't that be the expected result (length>15)?
No. An instruction crossing the boundary looks like: e.g. nextrip = 0x3, rip = 0xfffffffffffffffe As this is all evaluated in unsigned long arithmetic, nextrip - rip evaluates to 5, which is correct. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
