| Message ID | 1484849955-1871-5-git-send-email-will.deacon@arm.com |
|---|---|
| State | Accepted |
| Commit | 4a8d8a14c0d08c2437cb80c05e88f6cc1ca3fb2c |
| Headers | show |
| Series | Implement SMMU passthrough using the default domain | expand |
On 19/01/17 18:19, Will Deacon wrote: > The arm64 DMA-mapping implementation sets the DMA ops to the IOMMU DMA > ops if we detect that an IOMMU is present for the master and the DMA > ranges are valid. > > In the case when the IOMMU domain for the device is not of type > IOMMU_DOMAIN_DMA, then we have no business swizzling the ops, since > we're not in control of the underlying address space. This patch leaves > the DMA ops alone for masters attached to non-DMA IOMMU domains. In fact, I don't think there would be any harm in taking this one through arm64 straight away. The DMA ops can't be expected to work successfully on any old domain, so it's a reasonable sanity check regardless. Reviewed-by: Robin Murphy <robin.murphy@arm.com> > Signed-off-by: Will Deacon <will.deacon@arm.com> > --- > arch/arm64/mm/dma-mapping.c | 17 ++++++++++++----- > 1 file changed, 12 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c > index e04082700bb1..5d3c6ad621e8 100644 > --- a/arch/arm64/mm/dma-mapping.c > +++ b/arch/arm64/mm/dma-mapping.c > @@ -831,14 +831,21 @@ static bool do_iommu_attach(struct device *dev, const struct iommu_ops *ops, > * then the IOMMU core will have already configured a group for this > * device, and allocated the default domain for that group. > */ > - if (!domain || iommu_dma_init_domain(domain, dma_base, size, dev)) { > - pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n", > - dev_name(dev)); > - return false; > + if (!domain) > + goto out_err; > + > + if (domain->type == IOMMU_DOMAIN_DMA) { > + if (iommu_dma_init_domain(domain, dma_base, size, dev)) > + goto out_err; > + > + dev->archdata.dma_ops = &iommu_dma_ops; > } > > - dev->archdata.dma_ops = &iommu_dma_ops; > return true; > +out_err: > + pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n", > + dev_name(dev)); > + return false; > } > > static void queue_iommu_attach(struct device *dev, const struct iommu_ops *ops, > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
On Thu, Jan 19, 2017 at 07:00:25PM +0000, Robin Murphy wrote: > On 19/01/17 18:19, Will Deacon wrote: > > The arm64 DMA-mapping implementation sets the DMA ops to the IOMMU DMA > > ops if we detect that an IOMMU is present for the master and the DMA > > ranges are valid. > > > > In the case when the IOMMU domain for the device is not of type > > IOMMU_DOMAIN_DMA, then we have no business swizzling the ops, since > > we're not in control of the underlying address space. This patch leaves > > the DMA ops alone for masters attached to non-DMA IOMMU domains. > > In fact, I don't think there would be any harm in taking this one > through arm64 straight away. The DMA ops can't be expected to work > successfully on any old domain, so it's a reasonable sanity check > regardless. > > Reviewed-by: Robin Murphy <robin.murphy@arm.com> Good point; I'll queue this one for 4.11 via arm64. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index e04082700bb1..5d3c6ad621e8 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -831,14 +831,21 @@ static bool do_iommu_attach(struct device *dev, const struct iommu_ops *ops, * then the IOMMU core will have already configured a group for this * device, and allocated the default domain for that group. */ - if (!domain || iommu_dma_init_domain(domain, dma_base, size, dev)) { - pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n", - dev_name(dev)); - return false; + if (!domain) + goto out_err; + + if (domain->type == IOMMU_DOMAIN_DMA) { + if (iommu_dma_init_domain(domain, dma_base, size, dev)) + goto out_err; + + dev->archdata.dma_ops = &iommu_dma_ops; } - dev->archdata.dma_ops = &iommu_dma_ops; return true; +out_err: + pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n", + dev_name(dev)); + return false; } static void queue_iommu_attach(struct device *dev, const struct iommu_ops *ops,
The arm64 DMA-mapping implementation sets the DMA ops to the IOMMU DMA ops if we detect that an IOMMU is present for the master and the DMA ranges are valid. In the case when the IOMMU domain for the device is not of type IOMMU_DOMAIN_DMA, then we have no business swizzling the ops, since we're not in control of the underlying address space. This patch leaves the DMA ops alone for masters attached to non-DMA IOMMU domains. Signed-off-by: Will Deacon <will.deacon@arm.com> --- arch/arm64/mm/dma-mapping.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) -- 2.1.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel