From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Subject: Re: [PATCH] kvm/ppc/booke64: fix build breakage from Altivec, and disable e6500 Date: Fri, 10 May 2013 13:23:13 -0500 Message-ID: <1368210193.19683.6@snotra> References: <1368155698-15784-1-git-send-email-scottwood@freescale.com> <300B73AA675FCE4A93EB4FC1D42459FF3FE2FA@039-SN2MPN1-011.039d.mgd.msft.net> <0FD00883-6578-4AE0-A8A6-AAC6FD050870@suse.de> <300B73AA675FCE4A93EB4FC1D42459FF4059B5@039-SN2MPN1-013.039d.mgd.msft.net> <1368207728.19683.2@snotra> <300B73AA675FCE4A93EB4FC1D42459FF408089@039-SN2MPN1-013.039d.mgd.msft.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; delsp=Yes; format=Flowed Content-Transfer-Encoding: 8BIT Cc: Wood Scott-B07421 , Alexander Graf , "kvm-ppc@vger.kernel.org" , "kvm@vger.kernel.org" To: Caraman Mihai Claudiu-B02008 Return-path: In-Reply-To: <300B73AA675FCE4A93EB4FC1D42459FF408089@039-SN2MPN1-013.039d.mgd.msft.net> (from B02008@freescale.com on Fri May 10 13:20:33 2013) Content-Disposition: inline Sender: kvm-ppc-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 05/10/2013 01:20:33 PM, Caraman Mihai Claudiu-B02008 wrote: > > > > -----Original Message----- > > From: Wood Scott-B07421 > > Sent: Friday, May 10, 2013 8:42 PM > > To: Caraman Mihai Claudiu-B02008 > > Cc: Alexander Graf; Wood Scott-B07421; kvm-ppc@vger.kernel.org; > > kvm@vger.kernel.org > > Subject: Re: [PATCH] kvm/ppc/booke64: fix build breakage from > Altivec, > > and disable e6500 > > > > On 05/10/2013 09:11:24 AM, Caraman Mihai Claudiu-B02008 wrote: > > > > -----Original Message----- > > > > From: Alexander Graf [mailto:agraf@suse.de] > > > > Sent: Friday, May 10, 2013 4:16 PM > > > > To: Caraman Mihai Claudiu-B02008 > > > > Cc: Wood Scott-B07421; kvm-ppc@vger.kernel.org; > kvm@vger.kernel.org > > > > Subject: Re: [PATCH] kvm/ppc/booke64: fix build breakage from > > > Altivec, > > > > and disable e6500 > > > > > > > > > > > > On 10.05.2013, at 11:40, Caraman Mihai Claudiu-B02008 wrote: > > > > > > > > >> -----Original Message----- > > > > >> From: Wood Scott-B07421 > > > > >> Sent: Friday, May 10, 2013 6:15 AM > > > > >> To: Alexander Graf > > > > >> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; Wood > > > Scott-B07421; > > > > >> Caraman Mihai Claudiu-B02008 > > > > >> Subject: [PATCH] kvm/ppc/booke64: fix build breakage from > > > Altivec, and > > > > >> disable e6500 > > > > >> > > > > >> BookE altivec support brought two new exceptions, but KVM > was not > > > > >> updated, so the build broke for all 64-bit booke with KVM > > > enabled. > > > > > > > > > > We couldn't do that in KVM before having > > > > BOOKE_INTERRUPT_ALTIVEC_UNAVAIL/ > > > > > BOOKE_INTERRUPT_ALTIVEC_ASSIST. As Tiejun noticed earlier we > > > should > > > > have > > > > > done this in Kumar's tree but we missed that chance. We will > face > > > > similar > > > > > issues every time an exception handler will be added. > > > > > > > > How hard would it be to add? I suppose it's broken in 3.10, so > we > > > need > > > > something quick before it gets released? > > > > > > Not so hard. Yes. I was surprised by this patch given the fact > that > > > we have > > > planned to send altivec support upstream this days and that we > > > already have > > > a similar patch from Tiejun on our list. > > > > I didn't see Tiejun's patch... My goal was just to fix the build > break > > without exposing problems, and to encourage a patch to fix it > properly > > to happen sooner rather than later. With Tiejun's patch, which is > > similar to mine except that it doesn't disable e6500 support, a user > > could BUG() the kernel by forcing an Altivec exception in a guest. > I > > didn't want to go further down the road of adding reflectors for > those > > exceptions, which could make it look like the problem was dealt with > > even though it's still not done. > > I agree it's quite annoying to hit a build breakage. Reflection is not > a proper solution for this problem (though we will require it later) > but program exception injection looks feasible as a simple fix. Program exception injection still doesn't deal with state corruption. > I wouldn't want to see e6500 removed for this reason. It's not being removed, just closed while under construction to prevent damage to people passing through. :-) -Scott