From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH] KVM: APIC: avoid instruction emulation for EOI writes Date: Sun, 11 Sep 2011 10:05:11 +0200 Message-ID: <4E6C6BB7.1050607@web.de> References: <625BA99ED14B2D499DC4E29D8138F15063045B0C0C@shsmsx502.ccr.corp.intel.com> <4E5B68DA.1090208@siemens.com> <4E5B70F8.30307@redhat.com> <4E5B7206.5070603@siemens.com> <4E5B73CC.5080800@redhat.com> <4E5B9A3B.2020009@siemens.com> <4E5B9EC0.2010808@redhat.com> <4E6C5F14.1030407@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig80D96169C313834639BD5D42" Cc: ya su , "Tian, Kevin" , "kvm@vger.kernel.org" , "Nakajima, Jun" , "Dong, Eddie" , Marcelo Tosatti To: Avi Kivity Return-path: Received: from fmmailgate03.web.de ([217.72.192.234]:44082 "EHLO fmmailgate03.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752428Ab1IKIFO (ORCPT ); Sun, 11 Sep 2011 04:05:14 -0400 In-Reply-To: <4E6C5F14.1030407@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig80D96169C313834639BD5D42 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 2011-09-11 09:11, Avi Kivity wrote: > On 09/10/2011 11:41 AM, ya su wrote: >> 0x80637b85: testl $0x1000, 0xfffe0300 >> 0x80637b8f: jne 0x80637b85 >> 0x80637b91: mov %ecx, 0xfffe0300 >> 0x80637b97: testl $0x1000, 0xfffe0300 >> 0x80637ba1: jne 0x80637b97 >> >> I wonder why testl operation will also cause a ICR write, from th= e >> asm code, there should only issue one IPI, but from trace-cmd, it >> issued 3 IPI, is there something wrong? >=20 > It's a bug in test insn emulation, coincidentally I wrote a patch to fi= x > it yesterday, not imagining that it actually happens in practice. >=20 >> Is it also possible to optimize ICR write emulation, from the >> result, winxp vm will produce a lot of ICR writes >> >=20 > Unfortunately not. I'm just hoping we'll see hardware-assisted APIC, ideally also IOAPIC virtualization soon. Jan --------------enig80D96169C313834639BD5D42 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk5sa7cACgkQitSsb3rl5xSj4wCgh15eeoj/hpB61ceDSrdTCIjx Nf0AoIkYPZhsdl9QbdWXw4G0pamD6S0u =2jil -----END PGP SIGNATURE----- --------------enig80D96169C313834639BD5D42--