From owner-freebsd-current@FreeBSD.ORG Tue Aug 5 13:04:15 2008 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 0D67A1065675; Tue, 5 Aug 2008 13:04:15 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (skuns.zoral.com.ua [91.193.166.194]) by mx1.freebsd.org (Postfix) with ESMTP id 950388FC15; Tue, 5 Aug 2008 13:04:14 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id m75D49ep078955 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 5 Aug 2008 16:04:10 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.2/8.14.2) with ESMTP id m75D49U7006397; Tue, 5 Aug 2008 16:04:09 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.2/8.14.2/Submit) id m75D49RA006380; Tue, 5 Aug 2008 16:04:09 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Tue, 5 Aug 2008 16:04:09 +0300 From: Kostik Belousov To: Stanislav Sedov Message-ID: <20080805130409.GF97161@deviant.kiev.zoral.com.ua> References: <1212758604.1904.33.camel@localhost> <20080615230250.7f3efae4.stas@FreeBSD.org> <1213557999.1816.15.camel@localhost> <20080616204433.48ad9879.stas@FreeBSD.org> <20080616222740.5cdd9490.stas@FreeBSD.org> <1213641761.2184.0.camel@localhost> <20080805140324.9f53ba9b.stas@FreeBSD.org> <20080805115315.GE97161@deviant.kiev.zoral.com.ua> <20080805161520.90001117.stas@FreeBSD.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="uQKdfr6GvE2xHbL0" Content-Disposition: inline In-Reply-To: <20080805161520.90001117.stas@FreeBSD.org> User-Agent: Mutt/1.4.2.3i X-Spam-Status: No, score=-4.4 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua Cc: Peter Jeremy , Poul-Henning Kamp , Rui Paulo , current@freebsd.org, Coleman Kane Subject: Re: cpuctl(formely devcpu) patch test request X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 05 Aug 2008 13:04:15 -0000 --uQKdfr6GvE2xHbL0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Aug 05, 2008 at 04:15:20PM +0400, Stanislav Sedov wrote: > On Tue, 5 Aug 2008 14:53:15 +0300 > Kostik Belousov mentioned: >=20 > > On Tue, Aug 05, 2008 at 02:03:24PM +0400, Stanislav Sedov wrote: > > > On Mon, 16 Jun 2008 14:42:41 -0400 > > > Coleman Kane mentioned: > > >=20 > > > >=20 > > > > Is it potentially "unsafe" to use RDMSR? > > > > > > >=20 > > > Well, it might disclose some sensitive information, > > > as well as create covert channels. E.g. some of the > > > registers contains kernel thread pointers, etc; some > > > of them undocumented. It won't be very wise to give > > > access to the rdmsr feature to all users on a > > > multi-user machine. > > >=20 > > > Sorry for this taking so long. You messages spotted > > > a bug in my security model for this driver, so I've > > > redone that. Now, the access to the rdmsr and cpuid > > > features will be granted only if the caller has > > > read permissions on the device, and wrmsr/update > > > - only if he've opened the device for writing. > > > This way you can provide fine-grained control to > > > the driver features. > > >=20 > > > I've also added the cpucontrol utility which provided > > > userland accesss to the driver, and allows to apply > > > microcode updates. > > >=20 > > > The latest patch against HEAD is available here: > > > ftp://ftp.SpringDaemons.com/dustheap/cpuctl.4.diff > > >=20 > > > Thanks! > >=20 > > --- a/sys/amd64/amd64/support.S > > +++ b/sys/amd64/amd64/support.S > > @@ -765,6 +765,7 @@ ENTRY(wrmsr_safe) > > */ > > ALIGN_TEXT > > msr_onfault: > > - movq $0,PCB_ONFAULT(%r8) > > - movl $EFAULT,%eax > > + movq PCPU(CURPCB),%r8 /* set fault handler */ > > + movq $0,PCB_ONFAULT(%r8) > > + movq $EFAULT,%rax > > ret > >=20 > > movq $EFAULT,%rax is better to be replaced by movl, %eax. Amd64 specifi= es > > automatic zeroing of the upper-half of the registers on the 32bit opera= tion. > >=20 >=20 > Yeah, it seems that I thought about this initially, but decided > that this was unsafe lately. Thanks for suggestion! >=20 > There's a fixed version: > ftp://ftp.SpringDaemons.com/dustheap/cpuctl.5.diff Ok. I noted cpucontrol(8) only after trying to import the rev5 patch. I do not suggest changing it, but what are the reasons for the microcode patch headers definitions to be private for the cpucontrol, instead of being put into the machine/.h ? --uQKdfr6GvE2xHbL0 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (FreeBSD) iEYEARECAAYFAkiYT8gACgkQC3+MBN1Mb4ij0ACg2J0tWNk2jWnLkV/PsDp8Yb5y 9JEAoIRCBP6v1WGiF+CidtHd7AMOuATg =DTLx -----END PGP SIGNATURE----- --uQKdfr6GvE2xHbL0--