Hi Ashutosh, On Fri, Nov 21, 2014 at 2:07 AM, Ashutosh Kumar <mrashut...@hotmail.com> wrote: > Yes you are right 'repz' prefixes is added to the ‘cmps’ and 'scas' > instructions. > > The actual opcode is “F3 A5” which is ‘rep movs’ (disassembly is showing > ‘repz’). > > > > Yes the guest is emitting these instructions to access MMIO (local apic) >
Bummer. I was hoping that it was a prefix stuck by the compiler for optimization (that could be ignored): http://repzret.org/p/repzret/ In any case, the primitives you will need to emulate MOVS exist in vmm_instruction_emul.c. I don't have any plans to work on this but would be happy to review/submit the patch that does the emulation. best Neel > > > Regards > Ashutosh > > >> Date: Fri, 21 Nov 2014 00:08:15 -0800 >> Subject: Re: 'repz' instruction not supported. >> From: neeln...@gmail.com >> To: mrashut...@hotmail.com >> CC: firstname.lastname@example.org > >> >> Hi Ashutosh, >> >> On Wed, Nov 19, 2014 at 10:30 PM, Ashutosh Kumar <mrashut...@hotmail.com> >> wrote: >> > Hi >> > We have found that emulation of 'repz' instruction is not supported in >> > bhyve. This is causing VM_EXIT for Guest OS. Do we have plans to add >> > support >> > for instructions like 'repz'. >> > >> >> 'repz' is actually an instruction prefix. The two instructions with >> which 'repz' is allowed are 'cmps' and 'scas'. Both these instructions >> typically don't need to be emulated since they operate on strings in >> "regular" guest memory. >> >> Is your guest emitting these instructions to access MMIO? Can you >> share an objdump with the offending instructions? >> >> best >> Neel >> >> > RegardsAshutosh >> > _______________________________________________ >> > email@example.com mailing list >> > http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization >> > To unsubscribe, send any mail to >> > "freebsd-virtualization-unsubscr...@freebsd.org" _______________________________________________ firstname.lastname@example.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization To unsubscribe, send any mail to "freebsd-virtualization-unsubscr...@freebsd.org"