Hi BaoLu, On Fri, 18 Mar 2022 20:43:54 +0800, Lu Baolu <baolu...@linux.intel.com> wrote:
> On 2022/3/15 13:07, Jacob Pan wrote: > > DMA mapping API is the de facto standard for in-kernel DMA. It operates > > on a per device/RID basis which is not PASID-aware. > > > > Some modern devices such as Intel Data Streaming Accelerator, PASID is > > required for certain work submissions. To allow such devices use DMA > > mapping API, we need the following functionalities: > > 1. Provide device a way to retrieve a PASID for work submission within > > the kernel > > 2. Enable the kernel PASID on the IOMMU for the device > > 3. Attach the kernel PASID to the device's default DMA domain, let it > > be IOVA or physical address in case of pass-through. > > > > This patch introduces a driver facing API that enables DMA API > > PASID usage. Once enabled, device drivers can continue to use DMA APIs > > as is. There is no difference in dma_handle between without PASID and > > with PASID. > > > > Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com> > > --- > > drivers/iommu/dma-iommu.c | 65 +++++++++++++++++++++++++++++++++++++++ > > include/linux/dma-iommu.h | 7 +++++ > > include/linux/iommu.h | 9 ++++++ > > 3 files changed, 81 insertions(+) > > > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > > index b22034975301..d0ff1a34b1b6 100644 > > --- a/drivers/iommu/dma-iommu.c > > +++ b/drivers/iommu/dma-iommu.c > > @@ -39,6 +39,8 @@ enum iommu_dma_cookie_type { > > IOMMU_DMA_MSI_COOKIE, > > }; > > > > +static DECLARE_IOASID_SET(iommu_dma_pasid); > > + > > struct iommu_dma_cookie { > > enum iommu_dma_cookie_type type; > > union { > > @@ -370,6 +372,69 @@ void iommu_put_dma_cookie(struct iommu_domain > > *domain) domain->iova_cookie = NULL; > > } > > > > +/** > > + * iommu_enable_pasid_dma --Enable in-kernel DMA request with PASID > > + * @dev: Device to be enabled > > + * > > + * DMA request with PASID will be mapped the same way as the legacy > > DMA. > > + * If the device is in pass-through, PASID will also pass-through. If > > the > > + * device is in IOVA map, the supervisor PASID will point to the same > > IOVA > > + * page table. > > + * > > + * @return the kernel PASID to be used for DMA or INVALID_IOASID on > > failure > > The comment on the return value should be rephrased according to the > real code. > yes, will do. > > + */ > > +int iommu_enable_pasid_dma(struct device *dev, ioasid_t *pasid) > > +{ > > + struct iommu_domain *dom; > > + ioasid_t id, max; > > + int ret; > > + > > + dom = iommu_get_domain_for_dev(dev); > > + if (!dom || !dom->ops || !dom->ops->attach_dev_pasid) > > + return -ENODEV; > > + max = iommu_get_dev_pasid_max(dev); > > + if (!max) > > + return -EINVAL; > > + > > + id = ioasid_alloc(&iommu_dma_pasid, 1, max, dev); > > + if (id == INVALID_IOASID) > > + return -ENOMEM; > > + > > + ret = dom->ops->attach_dev_pasid(dom, dev, id); > > + if (ret) { > > + ioasid_put(id); > > + return ret; > > + } > > + *pasid = id; > > + > > + return ret; > > +} > > +EXPORT_SYMBOL(iommu_enable_pasid_dma); > > + > > +/** > > + * iommu_disable_pasid_dma --Disable in-kernel DMA request with PASID > > + * @dev: Device's PASID DMA to be disabled > > + * > > + * It is the device driver's responsibility to ensure no more incoming > > DMA > > + * requests with the kernel PASID before calling this function. IOMMU > > driver > > + * ensures PASID cache, IOTLBs related to the kernel PASID are cleared > > and > > + * drained. > > + * > > + * @return 0 on success or error code on failure > > Ditto. > same > > + */ > > +void iommu_disable_pasid_dma(struct device *dev, ioasid_t pasid) > > +{ > > + struct iommu_domain *dom; > > + > > + /* TODO: check the given PASID is within the ioasid_set */ > > + dom = iommu_get_domain_for_dev(dev); > > + if (!dom->ops->detach_dev_pasid) > > + return; > > + dom->ops->detach_dev_pasid(dom, dev, pasid); > > + ioasid_put(pasid); > > +} > > +EXPORT_SYMBOL(iommu_disable_pasid_dma); > > + > > /** > > * iommu_dma_get_resv_regions - Reserved region driver helper > > * @dev: Device from iommu_get_resv_regions() > > diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h > > index 24607dc3c2ac..e6cb9b52a420 100644 > > --- a/include/linux/dma-iommu.h > > +++ b/include/linux/dma-iommu.h > > @@ -18,6 +18,13 @@ int iommu_get_dma_cookie(struct iommu_domain > > *domain); int iommu_get_msi_cookie(struct iommu_domain *domain, > > dma_addr_t base); void iommu_put_dma_cookie(struct iommu_domain > > *domain); > > +/* > > + * For devices that can do DMA request with PASID, setup a system > > PASID. > > + * Address modes (IOVA, PA) are selected by the platform code. > > + */ > > No need for a comment here. Or move it to the function if need. > right, this comment is obsolete. will remove. > > +int iommu_enable_pasid_dma(struct device *dev, ioasid_t *pasid); > > +void iommu_disable_pasid_dma(struct device *dev, ioasid_t pasid); > > + > > /* Setup call for arch DMA mapping code */ > > void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 > > dma_limit); int iommu_dma_init_fq(struct iommu_domain *domain); > > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > > index fde5b933dbe3..fb011722e4f8 100644 > > --- a/include/linux/iommu.h > > +++ b/include/linux/iommu.h > > @@ -395,6 +395,15 @@ static inline void iommu_set_dev_pasid_max(struct > > device *dev, > > param->pasid_max = max; > > } > > +static inline ioasid_t iommu_get_dev_pasid_max(struct device *dev) > > +{ > > + struct dev_iommu *param = dev->iommu; > > + > > + if (WARN_ON(!param)) > > + return 0; > > + > > + return param->pasid_max; > > +} > > > > int iommu_device_register(struct iommu_device *iommu, > > const struct iommu_ops *ops, > > Best regards, > baolu Thanks, Jacob _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu