Date: Sun, 23 Nov 2014 06:04:06 +0000 From: Ashutosh Kumar <mrashutosh@hotmail.com> To: <neelnatu@gmail.com> Cc: freebsd-virtualization@freebsd.org Subject: RE: 'repz' instruction not supported. Message-ID: <SNT150-W46C137D7FD2D4868D97E2CDF750@phx.gbl> In-Reply-To: <CAFgRE9GFuYQMcJOrQKjNbB1UFhFEYtWvnmGBwpfrLP=wN1FU7w@mail.gmail.com> References: <SNT150-W871C393630F3047CD01F1DF760@phx.gbl>, <CAFgRE9F6MgjdMqz-kT3hvgB6YDwrxijoEVnGBFJfahK5mNpRrA@mail.gmail.com>, <SNT150-W9ABC2BDA289ECE6910E56DF770@phx.gbl>, <CAFgRE9GFuYQMcJOrQKjNbB1UFhFEYtWvnmGBwpfrLP=wN1FU7w@mail.gmail.com>
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Thanks. Will share the code sometime this week with you. Regards Ashutosh > Date: Fri=2C 21 Nov 2014 11:22:06 -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 Fri=2C Nov 21=2C 2014 at 2:07 AM=2C Ashutosh Kumar <mrashutosh@hotmail= .com> wrote: > > Yes you are right 'repz' prefixes is added to the =91cmps=92 and 'scas' > > instructions. > > > > The actual opcode is =93F3 A5=94 which is =91rep movs=92 (disassembly i= s showing > > =91repz=92). > > > > > > > > Yes the guest is emitting these instructions to access MMIO (local apic= ) > > >=20 > Bummer. >=20 > I was hoping that it was a prefix stuck by the compiler for > optimization (that could be ignored): > http://repzret.org/p/repzret/ >=20 > In any case=2C 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. >=20 > best > Neel >=20 > > > > > > Regards > > Ashutosh > > > > > >> 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 > > > >> > >> Hi Ashutosh=2C > >> > >> On Wed=2C Nov 19=2C 2014 at 10:30 PM=2C Ashutosh Kumar <mrashutosh@hot= mail.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 > >> > _______________________________________________ > >> > 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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