Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761835Ab3DCP4F (ORCPT ); Wed, 3 Apr 2013 11:56:05 -0400 Received: from co9ehsobe002.messaging.microsoft.com ([207.46.163.25]:24346 "EHLO co9outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761643Ab3DCP4D convert rfc822-to-8bit (ORCPT ); Wed, 3 Apr 2013 11:56:03 -0400 X-Forefront-Antispam-Report: CIP:70.37.183.190;KIP:(null);UIP:(null);IPV:NLI;H:mail.freescale.net;RD:none;EFVD:NLI X-SpamScore: -4 X-BigFish: VS-4(zzbb2dI98dI9371I542I1432Izz1f42h1fc6h1ee6h1de0h1202h1e76h1d1ah1d2ahzz8275dhz2dh2a8h668h839h8e2h8e3h944hd25hf0ah1220h1288h12a5h12a9h12bdh137ah13b6h1441h1504h1537h153bh15d0h162dh1631h1758h18e1h1946h19b5h1ad9h1b0ahbe9i1155h) From: Yoder Stuart-B08248 To: Sethi Varun-B16395 , Wood Scott-B07421 , Timur Tabi CC: Joerg Roedel , lkml , Kumar Gala , "iommu@lists.linux-foundation.org" , Benjamin Herrenschmidt , "linuxppc-dev@lists.ozlabs.org" Subject: RE: [PATCH 5/5 v11] iommu/fsl: Freescale PAMU driver and iommu implementation. Thread-Topic: [PATCH 5/5 v11] iommu/fsl: Freescale PAMU driver and iommu implementation. Thread-Index: AQHOMA3mO/4GVyqmPkuty25lenzG/ZjD84EAgACzKZA= Date: Wed, 3 Apr 2013 15:55:36 +0000 Message-ID: <9F6FE96B71CF29479FF1CDC8046E15035A1B2E@039-SN1MPN1-003.039d.mgd.msft.net> References: (from timur@tabi.org on Tue Apr 2 20:35:54 2013) <1364953950.8690.4@snotra> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.214.84.198] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-OriginatorOrg: freescale.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2352 Lines: 56 > -----Original Message----- > From: Sethi Varun-B16395 > Sent: Wednesday, April 03, 2013 12:12 AM > To: Wood Scott-B07421; Timur Tabi > Cc: Joerg Roedel; lkml; Kumar Gala; Yoder Stuart-B08248; iommu@lists.linux-foundation.org; Benjamin > Herrenschmidt; linuxppc-dev@lists.ozlabs.org > Subject: RE: [PATCH 5/5 v11] iommu/fsl: Freescale PAMU driver and iommu implementation. > > > > > -----Original Message----- > > From: Wood Scott-B07421 > > Sent: Wednesday, April 03, 2013 7:23 AM > > To: Timur Tabi > > Cc: Joerg Roedel; Sethi Varun-B16395; lkml; Kumar Gala; Yoder Stuart- > > B08248; iommu@lists.linux-foundation.org; Benjamin Herrenschmidt; > > linuxppc-dev@lists.ozlabs.org > > Subject: Re: [PATCH 5/5 v11] iommu/fsl: Freescale PAMU driver and iommu > > implementation. > > > > On 04/02/2013 08:35:54 PM, Timur Tabi wrote: > > > On Tue, Apr 2, 2013 at 11:18 AM, Joerg Roedel wrote: > > > > > > > > + panic("\n"); > > > > > > > > A kernel panic seems like an over-reaction to an access violation. > > > > > > We have no way to determining what code caused the violation, so we > > > can't just kill the process. I agree it seems like overkill, but what > > > else should we do? Does the IOMMU layer have a way for the IOMMU > > > driver to stop the device that caused the problem? > > > > At a minimum, log a message and continue. Probably turn off the LIODN, > > at least if it continues to be noisy (otherwise we could get stuck in an > > interrupt storm as you note). Possibly let the user know somehow, > > especially if it's a VFIO domain. > [Sethi Varun-B16395] Can definitely log the message and disable the LIODN (to avoid an interrupt storm), > but > we definitely need a mechanism to inform vfio subsystem about the error. Also, disabling LIODN may not > be a viable > option with the new LIODN allocation scheme (where LIODN would be associated with a domain). I think for phase 1 of this, just log the error, shut down DMA as you described. We can implement more full featured error management, like notifying vfio or the VM somehow in the future. Stuart -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/