From owner-freebsd-virtualization@FreeBSD.ORG Fri Nov 21 10:08:15 2014 Return-Path: Delivered-To: freebsd-virtualization@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 6277AE04 for ; Fri, 21 Nov 2014 10:08:15 +0000 (UTC) Received: from SNT004-OMC1S44.hotmail.com (snt004-omc1s44.hotmail.com [65.54.61.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (Client CN "*.outlook.com", Issuer "MSIT Machine Auth CA 2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 3A03C8BF for ; Fri, 21 Nov 2014 10:08:15 +0000 (UTC) Received: from SNT150-W9 ([65.55.90.9]) by SNT004-OMC1S44.hotmail.com over TLS secured channel with Microsoft SMTPSVC(7.5.7601.22751); Fri, 21 Nov 2014 02:07:08 -0800 X-TMN: [UgYeEPh+sOGjXsnBCYrK9xo8/iCe8sGE] X-Originating-Email: [mrashutosh@hotmail.com] Message-ID: From: Ashutosh Kumar To: Neel Natu Subject: RE: 'repz' instruction not supported. Date: Fri, 21 Nov 2014 10:07:08 +0000 Importance: Normal In-Reply-To: References: , MIME-Version: 1.0 X-OriginalArrivalTime: 21 Nov 2014 10:07:08.0678 (UTC) FILETIME=[E8F8E260:01D00572] Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.18-1 Cc: "freebsd-virtualization@freebsd.org" X-BeenThere: freebsd-virtualization@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: "Discussion of various virtualization techniques FreeBSD supports." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 21 Nov 2014 10:08:15 -0000 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 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" =