Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756810Ab3JNPRx (ORCPT ); Mon, 14 Oct 2013 11:17:53 -0400 Received: from mail-pb0-f50.google.com ([209.85.160.50]:47744 "EHLO mail-pb0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756605Ab3JNPRv (ORCPT ); Mon, 14 Oct 2013 11:17:51 -0400 MIME-Version: 1.0 X-Originating-IP: [2a01:e35:2434:4600:91ce:e2b8:d002:9a5c] In-Reply-To: <20131014124837.GD10491@mudshark.cambridge.arm.com> References: <1381497887-14586-1-git-send-email-a.motakis@virtualopensystems.com> <1381497887-14586-2-git-send-email-a.motakis@virtualopensystems.com> <20131014124837.GD10491@mudshark.cambridge.arm.com> Date: Mon, 14 Oct 2013 17:17:51 +0200 Message-ID: Subject: Re: [PATCH 2/2] ARM: SMMU: return NULL on error in arm_smmu_iova_to_phys From: Antonios Motakis To: Will Deacon Cc: Joerg Roedel , "moderated list:ARM SMMU DRIVER" , "open list:IOMMU DRIVERS" , open list , "kvmarm@lists.cs.columbia.edu" , "tech@virtualopensystems.com" , "agraf@suse.de" , "B08248@freescale.com" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1842 Lines: 44 On Mon, Oct 14, 2013 at 2:48 PM, Will Deacon wrote: > On Fri, Oct 11, 2013 at 02:24:47PM +0100, Antonios Motakis wrote: >> The return value of arm_smmu_iova_to_phys is directly passed to the >> user of the IOMMU API via iommu_iova_to_phys; however the ARM SMMU >> driver returns -EINVAL on error, which is not consistent with the >> rest of the drivers implementing the IOMMU API. VFIO also relies on >> the call returning NULL when a page has not been mapped already. >> >> Signed-off-by: Antonios Motakis >> --- >> drivers/iommu/arm-smmu.c | 5 +---- >> 1 file changed, 1 insertion(+), 4 deletions(-) >> >> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c >> index 8b71332..fe81b20 100644 >> --- a/drivers/iommu/arm-smmu.c >> +++ b/drivers/iommu/arm-smmu.c >> @@ -1480,10 +1480,7 @@ static phys_addr_t arm_smmu_iova_to_phys(struct iommu_domain *domain, >> >> err_unlock: >> spin_unlock(&smmu_domain->lock); >> - dev_warn(smmu->dev, >> - "invalid (corrupt?) page tables detected for iova 0x%llx\n", >> - (unsigned long long)iova); >> - return -EINVAL; >> + return NULL; > > Why are you removing the warning message? VFIO will exercise this code path every time when mapping DMA memory. This is normal and VFIO *expects* the function to fail - it is only if the function succeeds that VFIO needs to back down from the DMA mapping and fail. This means that there would be a warning every time a VFIO user maps some memory for DMA use, even though nothing went wrong. > > Will -- 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/