From: Lu Baolu <baolu.lu@linux.intel.com> To: Christoph Hellwig <hch@infradead.org> Cc: baolu.lu@linux.intel.com, David Woodhouse <dwmw2@infradead.org>, Joerg Roedel <joro@8bytes.org>, kevin.tian@intel.com, ashok.raj@intel.com, dima@arista.com, tmurphy@arista.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, jacob.jun.pan@intel.com Subject: Re: [PATCH v3 5/8] iommu/vt-d: Implement def_domain_type iommu ops entry Date: Tue, 30 Apr 2019 10:11:42 +0800 [thread overview] Message-ID: <9c1d1e16-fdab-0494-8720-97ff20013da4@linux.intel.com> (raw) In-Reply-To: <20190429200338.GA8412@infradead.org> Hi Christoph, On 4/30/19 4:03 AM, Christoph Hellwig wrote: >> @@ -3631,35 +3607,30 @@ static int iommu_no_mapping(struct device *dev) >> if (iommu_dummy(dev)) >> return 1; >> >> - if (!iommu_identity_mapping) >> - return 0; >> - > > FYI, iommu_no_mapping has been refactored in for-next: > > https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git/commit/?h=x86/vt-d&id=48b2c937ea37a3bece0094b46450ed5267525289 Oh, yes! Thanks for letting me know this. Will rebase the code. > >> found = identity_mapping(dev); >> if (found) { >> + /* >> + * If the device's dma_mask is less than the system's memory >> + * size then this is not a candidate for identity mapping. >> + */ >> + u64 dma_mask = *dev->dma_mask; >> + >> + if (dev->coherent_dma_mask && >> + dev->coherent_dma_mask < dma_mask) >> + dma_mask = dev->coherent_dma_mask; >> + >> + if (dma_mask < dma_get_required_mask(dev)) { > > I know this is mostly existing code moved around, but it really needs > some fixing. For one dma_get_required_mask is supposed to return the > required to not bounce mask for the given device. E.g. for a device > behind an iommu it should always just return 32-bit. If you really > want to check vs system memory please call dma_direct_get_required_mask > without the dma_ops indirection. > > Second I don't even think we need to check the coherent_dma_mask, > dma_direct is pretty good at always finding memory even without > an iommu. > > Third this doesn't take take the bus_dma_mask into account. > > This probably should just be: > > if (min(*dev->dma_mask, dev->bus_dma_mask) < > dma_direct_get_required_mask(dev)) { Agreed and will add this in the next version. Best regards, Lu Baolu
WARNING: multiple messages have this Message-ID (diff)
From: Lu Baolu <baolu.lu@linux.intel.com> To: Christoph Hellwig <hch@infradead.org> Cc: kevin.tian@intel.com, ashok.raj@intel.com, dima@arista.com, tmurphy@arista.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, jacob.jun.pan@intel.com, David Woodhouse <dwmw2@infradead.org> Subject: Re: [PATCH v3 5/8] iommu/vt-d: Implement def_domain_type iommu ops entry Date: Tue, 30 Apr 2019 10:11:42 +0800 [thread overview] Message-ID: <9c1d1e16-fdab-0494-8720-97ff20013da4@linux.intel.com> (raw) Message-ID: <20190430021142.OxNcsNuENvcbgnbdxES8rL1Ft-T7-tQAqRsb3deMM3U@z> (raw) In-Reply-To: <20190429200338.GA8412@infradead.org> Hi Christoph, On 4/30/19 4:03 AM, Christoph Hellwig wrote: >> @@ -3631,35 +3607,30 @@ static int iommu_no_mapping(struct device *dev) >> if (iommu_dummy(dev)) >> return 1; >> >> - if (!iommu_identity_mapping) >> - return 0; >> - > > FYI, iommu_no_mapping has been refactored in for-next: > > https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git/commit/?h=x86/vt-d&id=48b2c937ea37a3bece0094b46450ed5267525289 Oh, yes! Thanks for letting me know this. Will rebase the code. > >> found = identity_mapping(dev); >> if (found) { >> + /* >> + * If the device's dma_mask is less than the system's memory >> + * size then this is not a candidate for identity mapping. >> + */ >> + u64 dma_mask = *dev->dma_mask; >> + >> + if (dev->coherent_dma_mask && >> + dev->coherent_dma_mask < dma_mask) >> + dma_mask = dev->coherent_dma_mask; >> + >> + if (dma_mask < dma_get_required_mask(dev)) { > > I know this is mostly existing code moved around, but it really needs > some fixing. For one dma_get_required_mask is supposed to return the > required to not bounce mask for the given device. E.g. for a device > behind an iommu it should always just return 32-bit. If you really > want to check vs system memory please call dma_direct_get_required_mask > without the dma_ops indirection. > > Second I don't even think we need to check the coherent_dma_mask, > dma_direct is pretty good at always finding memory even without > an iommu. > > Third this doesn't take take the bus_dma_mask into account. > > This probably should just be: > > if (min(*dev->dma_mask, dev->bus_dma_mask) < > dma_direct_get_required_mask(dev)) { Agreed and will add this in the next version. Best regards, Lu Baolu _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2019-04-30 2:11 UTC|newest] Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-04-29 2:09 [PATCH v3 0/8] iommu/vt-d: Delegate DMA domain to generic iommu Lu Baolu 2019-04-29 2:09 ` Lu Baolu 2019-04-29 2:09 ` [PATCH v3 1/8] iommu: Add ops entry for supported default domain type Lu Baolu 2019-04-29 2:09 ` Lu Baolu 2019-05-06 15:32 ` Tom Murphy via iommu 2019-05-07 10:28 ` Robin Murphy 2019-05-09 2:30 ` Lu Baolu 2019-05-09 16:11 ` Robin Murphy 2019-05-10 5:29 ` Lu Baolu 2019-05-09 2:22 ` Lu Baolu 2019-04-29 2:09 ` [PATCH v3 2/8] iommu/vt-d: Implement apply_resv_region iommu ops entry Lu Baolu 2019-04-29 2:09 ` Lu Baolu 2019-04-29 2:09 ` [PATCH v3 3/8] iommu/vt-d: Expose ISA direct mapping region via iommu_get_resv_regions Lu Baolu 2019-04-29 2:09 ` Lu Baolu 2019-04-29 2:09 ` [PATCH v3 4/8] iommu/vt-d: Enable DMA remapping after rmrr mapped Lu Baolu 2019-04-29 2:09 ` Lu Baolu 2019-04-29 2:09 ` [PATCH v3 5/8] iommu/vt-d: Implement def_domain_type iommu ops entry Lu Baolu 2019-04-29 2:09 ` Lu Baolu 2019-04-29 20:03 ` Christoph Hellwig 2019-04-29 20:03 ` Christoph Hellwig 2019-04-30 2:11 ` Lu Baolu [this message] 2019-04-30 2:11 ` Lu Baolu 2019-05-06 15:25 ` Tom Murphy via iommu 2019-05-09 4:31 ` Lu Baolu 2019-04-29 2:09 ` [PATCH v3 6/8] iommu/vt-d: Allow DMA domains to be allocated by iommu ops Lu Baolu 2019-04-29 2:09 ` Lu Baolu 2019-04-29 2:09 ` [PATCH v3 7/8] iommu/vt-d: Remove lazy allocation of domains Lu Baolu 2019-04-29 2:09 ` Lu Baolu 2019-04-29 2:09 ` [PATCH v3 8/8] iommu/vt-d: Implement is_attach_deferred iommu ops entry Lu Baolu 2019-04-29 2:09 ` Lu Baolu
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