Date: Fri, 21 Nov 2014 10:07:08 +0000 From: Ashutosh Kumar <mrashutosh@hotmail.com> To: Neel Natu <neelnatu@gmail.com> Cc: "freebsd-virtualization@freebsd.org" <freebsd-virtualization@freebsd.org> Subject: RE: 'repz' instruction not supported. Message-ID: <SNT150-W9ABC2BDA289ECE6910E56DF770@phx.gbl> In-Reply-To: <CAFgRE9F6MgjdMqz-kT3hvgB6YDwrxijoEVnGBFJfahK5mNpRrA@mail.gmail.com> References: <SNT150-W871C393630F3047CD01F1DF760@phx.gbl>, <CAFgRE9F6MgjdMqz-kT3hvgB6YDwrxijoEVnGBFJfahK5mNpRrA@mail.gmail.com>
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Yes you are right 'repz' prefixes is added to the =91cmps=92 and 'scas' ins= tructions.=0A= =0A= The actual opcode is =93F3 A5=94 which is =91rep movs=92 (disassembly is sh= owing=0A= =91repz=92).=0A= =0A= =0A= =0A= Yes the guest is emitting these instructions to access MMIO=0A= (local apic) RegardsAshutosh > Date: Fri=2C 21 Nov 2014 00:08:15 -0800 > Subject: Re: 'repz' instruction not supported. > From: neelnatu@gmail.com > To: mrashutosh@hotmail.com > CC: freebsd-virtualization@freebsd.org >=20 > Hi Ashutosh=2C >=20 > On Wed=2C Nov 19=2C 2014 at 10:30 PM=2C Ashutosh Kumar <mrashutosh@hotmai= l.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 suppor= t for instructions like 'repz'. > > >=20 > '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. >=20 > Is your guest emitting these instructions to access MMIO? Can you > share an objdump with the offending instructions? >=20 > best > Neel >=20 > > RegardsAshutosh > > _______________________________________________ > > freebsd-virtualization@freebsd.org mailing list > > http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization > > To unsubscribe=2C send any mail to "freebsd-virtualization-unsubscribe@= freebsd.org" =
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