On Wed, Aug 28, 2019 at 07:14:42AM -0700, Christoph Hellwig wrote:
> With a little tweak to the intel-iommu code we should be able to work
> around the VMD mess for the requester IDs without having to create giant
> amounts of boilerplate DMA ops wrapping code. The other advantage of
> this scheme is that we can respect the real DMA masks for the actual
> devices, and I bet it will only be a matter of time until we'll see the
> first DMA challeneged NVMe devices.
This tests out fine on VMD hardware, but it's quite different than the
previous patch. In v1, the original dev was used in iommu_need_mapping(),
but this time it's the vmd device. Is this still using the actual device's
DMA mask then?
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> drivers/iommu/intel-iommu.c | 25 ++++++
> drivers/pci/controller/Kconfig | 1 -
> drivers/pci/controller/vmd.c | 150 ---------------------------------
> 3 files changed, 25 insertions(+), 151 deletions(-)
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 12d094d08c0a..aaa35ac73956 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -373,6 +373,23 @@ EXPORT_SYMBOL_GPL(intel_iommu_gfx_mapped);
> static DEFINE_SPINLOCK(device_domain_lock);
> static LIST_HEAD(device_domain_list);
>
> +/*
> + * For VMD we need to use the VMD devices for mapping requests instead of the
> + * actual device to get the proper PCIe requester ID.
> + */
> +static inline struct device *vmd_real_dev(struct device *dev)
> +{
> +#if IS_ENABLED(CONFIG_VMD)
> + if (dev_is_pci(dev)) {
> + struct pci_sysdata *sd = to_pci_dev(dev)->bus->sysdata;
> +
> + if (sd->vmd_dev)
> + return sd->vmd_dev;
> + }
> +#endif
> + return dev;
> +}
> +
> /*
> * Iterate over elements in device_domain_list and call the specified
> * callback @fn against each element.
> @@ -3520,6 +3537,7 @@ static dma_addr_t intel_map_page(struct device *dev, struct page *page,
> enum dma_data_direction dir,
> unsigned long attrs)
> {
> + dev = vmd_real_dev(dev);
> if (iommu_need_mapping(dev))
> return __intel_map_single(dev, page_to_phys(page) + offset,
> size, dir, *dev->dma_mask);
> @@ -3530,6 +3548,7 @@ static dma_addr_t intel_map_resource(struct device *dev, phys_addr_t phys_addr,
> size_t size, enum dma_data_direction dir,
> unsigned long attrs)
> {
> + dev = vmd_real_dev(dev);
> if (iommu_need_mapping(dev))
> return __intel_map_single(dev, phys_addr, size, dir,
> *dev->dma_mask);
> @@ -3585,6 +3604,7 @@ static void intel_unmap_page(struct device *dev, dma_addr_t dev_addr,
> size_t size, enum dma_data_direction dir,
> unsigned long attrs)
> {
> + dev = vmd_real_dev(dev);
> if (iommu_need_mapping(dev))
> intel_unmap(dev, dev_addr, size);
> else
> @@ -3594,6 +3614,7 @@ static void intel_unmap_page(struct device *dev, dma_addr_t dev_addr,
> static void intel_unmap_resource(struct device *dev, dma_addr_t dev_addr,
> size_t size, enum dma_data_direction dir, unsigned long attrs)
> {
> + dev = vmd_real_dev(dev);
> if (iommu_need_mapping(dev))
> intel_unmap(dev, dev_addr, size);
> }
> @@ -3605,6 +3626,7 @@ static void *intel_alloc_coherent(struct device *dev, size_t size,
> struct page *page = NULL;
> int order;
>
> + dev = vmd_real_dev(dev);
> if (!iommu_need_mapping(dev))
> return dma_direct_alloc(dev, size, dma_handle, flags, attrs);
>
> @@ -3641,6 +3663,7 @@ static void intel_free_coherent(struct device *dev, size_t size, void *vaddr,
> int order;
> struct page *page = virt_to_page(vaddr);
>
> + dev = vmd_real_dev(dev);
> if (!iommu_need_mapping(dev))
> return dma_direct_free(dev, size, vaddr, dma_handle, attrs);
>
> @@ -3661,6 +3684,7 @@ static void intel_unmap_sg(struct device *dev, struct scatterlist *sglist,
> struct scatterlist *sg;
> int i;
>
> + dev = vmd_real_dev(dev);
> if (!iommu_need_mapping(dev))
> return dma_direct_unmap_sg(dev, sglist, nelems, dir, attrs);
>
> @@ -3685,6 +3709,7 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele
> struct intel_iommu *iommu;
>
> BUG_ON(dir == DMA_NONE);
> + dev = vmd_real_dev(dev);
> if (!iommu_need_mapping(dev))
> return dma_direct_map_sg(dev, sglist, nelems, dir, attrs);
>
> diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
> index fe9f9f13ce11..920546cb84e2 100644
> --- a/drivers/pci/controller/Kconfig
> +++ b/drivers/pci/controller/Kconfig
> @@ -267,7 +267,6 @@ config PCIE_TANGO_SMP8759
>
> config VMD
> depends on PCI_MSI && X86_64 && SRCU
> - select X86_DEV_DMA_OPS
> tristate "Intel Volume Management Device Driver"
> ---help---
> Adds support for the Intel Volume Management Device (VMD). VMD is a
> diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
> index 785cb657c8c2..ba017ebba6a7 100644
> --- a/drivers/pci/controller/vmd.c
> +++ b/drivers/pci/controller/vmd.c
> @@ -94,9 +94,6 @@ struct vmd_dev {
> struct resource resources[3];
> struct irq_domain *irq_domain;
> struct pci_bus *bus;
> -
> - struct dma_map_ops dma_ops;
> - struct dma_domain dma_domain;
> };
>
> static inline struct vmd_dev *vmd_from_bus(struct pci_bus *bus)
> @@ -291,151 +288,6 @@ static struct msi_domain_info vmd_msi_domain_info = {
> .chip = &vmd_msi_controller,
> };
>
> -/*
> - * VMD replaces the requester ID with its own. DMA mappings for devices in a
> - * VMD domain need to be mapped for the VMD, not the device requiring
> - * the mapping.
> - */
> -static struct device *to_vmd_dev(struct device *dev)
> -{
> - struct pci_dev *pdev = to_pci_dev(dev);
> - struct vmd_dev *vmd = vmd_from_bus(pdev->bus);
> -
> - return &vmd->dev->dev;
> -}
> -
> -static void *vmd_alloc(struct device *dev, size_t size, dma_addr_t *addr,
> - gfp_t flag, unsigned long attrs)
> -{
> - return dma_alloc_attrs(to_vmd_dev(dev), size, addr, flag, attrs);
> -}
> -
> -static void vmd_free(struct device *dev, size_t size, void *vaddr,
> - dma_addr_t addr, unsigned long attrs)
> -{
> - return dma_free_attrs(to_vmd_dev(dev), size, vaddr, addr, attrs);
> -}
> -
> -static int vmd_mmap(struct device *dev, struct vm_area_struct *vma,
> - void *cpu_addr, dma_addr_t addr, size_t size,
> - unsigned long attrs)
> -{
> - return dma_mmap_attrs(to_vmd_dev(dev), vma, cpu_addr, addr, size,
> - attrs);
> -}
> -
> -static int vmd_get_sgtable(struct device *dev, struct sg_table *sgt,
> - void *cpu_addr, dma_addr_t addr, size_t size,
> - unsigned long attrs)
> -{
> - return dma_get_sgtable_attrs(to_vmd_dev(dev), sgt, cpu_addr, addr, size,
> - attrs);
> -}
> -
> -static dma_addr_t vmd_map_page(struct device *dev, struct page *page,
> - unsigned long offset, size_t size,
> - enum dma_data_direction dir,
> - unsigned long attrs)
> -{
> - return dma_map_page_attrs(to_vmd_dev(dev), page, offset, size, dir,
> - attrs);
> -}
> -
> -static void vmd_unmap_page(struct device *dev, dma_addr_t addr, size_t size,
> - enum dma_data_direction dir, unsigned long attrs)
> -{
> - dma_unmap_page_attrs(to_vmd_dev(dev), addr, size, dir, attrs);
> -}
> -
> -static int vmd_map_sg(struct device *dev, struct scatterlist *sg, int nents,
> - enum dma_data_direction dir, unsigned long attrs)
> -{
> - return dma_map_sg_attrs(to_vmd_dev(dev), sg, nents, dir, attrs);
> -}
> -
> -static void vmd_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
> - enum dma_data_direction dir, unsigned long attrs)
> -{
> - dma_unmap_sg_attrs(to_vmd_dev(dev), sg, nents, dir, attrs);
> -}
> -
> -static void vmd_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
> - size_t size, enum dma_data_direction dir)
> -{
> - dma_sync_single_for_cpu(to_vmd_dev(dev), addr, size, dir);
> -}
> -
> -static void vmd_sync_single_for_device(struct device *dev, dma_addr_t addr,
> - size_t size, enum dma_data_direction dir)
> -{
> - dma_sync_single_for_device(to_vmd_dev(dev), addr, size, dir);
> -}
> -
> -static void vmd_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
> - int nents, enum dma_data_direction dir)
> -{
> - dma_sync_sg_for_cpu(to_vmd_dev(dev), sg, nents, dir);
> -}
> -
> -static void vmd_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
> - int nents, enum dma_data_direction dir)
> -{
> - dma_sync_sg_for_device(to_vmd_dev(dev), sg, nents, dir);
> -}
> -
> -static int vmd_dma_supported(struct device *dev, u64 mask)
> -{
> - return dma_supported(to_vmd_dev(dev), mask);
> -}
> -
> -static u64 vmd_get_required_mask(struct device *dev)
> -{
> - return dma_get_required_mask(to_vmd_dev(dev));
> -}
> -
> -static void vmd_teardown_dma_ops(struct vmd_dev *vmd)
> -{
> - struct dma_domain *domain = &vmd->dma_domain;
> -
> - if (get_dma_ops(&vmd->dev->dev))
> - del_dma_domain(domain);
> -}
> -
> -#define ASSIGN_VMD_DMA_OPS(source, dest, fn) \
> - do { \
> - if (source->fn) \
> - dest->fn = vmd_##fn; \
> - } while (0)
> -
> -static void vmd_setup_dma_ops(struct vmd_dev *vmd)
> -{
> - const struct dma_map_ops *source = get_dma_ops(&vmd->dev->dev);
> - struct dma_map_ops *dest = &vmd->dma_ops;
> - struct dma_domain *domain = &vmd->dma_domain;
> -
> - domain->domain_nr = vmd->sysdata.domain;
> - domain->dma_ops = dest;
> -
> - if (!source)
> - return;
> - ASSIGN_VMD_DMA_OPS(source, dest, alloc);
> - ASSIGN_VMD_DMA_OPS(source, dest, free);
> - ASSIGN_VMD_DMA_OPS(source, dest, mmap);
> - ASSIGN_VMD_DMA_OPS(source, dest, get_sgtable);
> - ASSIGN_VMD_DMA_OPS(source, dest, map_page);
> - ASSIGN_VMD_DMA_OPS(source, dest, unmap_page);
> - ASSIGN_VMD_DMA_OPS(source, dest, map_sg);
> - ASSIGN_VMD_DMA_OPS(source, dest, unmap_sg);
> - ASSIGN_VMD_DMA_OPS(source, dest, sync_single_for_cpu);
> - ASSIGN_VMD_DMA_OPS(source, dest, sync_single_for_device);
> - ASSIGN_VMD_DMA_OPS(source, dest, sync_sg_for_cpu);
> - ASSIGN_VMD_DMA_OPS(source, dest, sync_sg_for_device);
> - ASSIGN_VMD_DMA_OPS(source, dest, dma_supported);
> - ASSIGN_VMD_DMA_OPS(source, dest, get_required_mask);
> - add_dma_domain(domain);
> -}
> -#undef ASSIGN_VMD_DMA_OPS
> -
> static char __iomem *vmd_cfg_addr(struct vmd_dev *vmd, struct pci_bus *bus,
> unsigned int devfn, int reg, int len)
> {
> @@ -690,7 +542,6 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
> }
>
> vmd_attach_resources(vmd);
> - vmd_setup_dma_ops(vmd);
> dev_set_msi_domain(&vmd->bus->dev, vmd->irq_domain);
>
> pci_scan_child_bus(vmd->bus);
> @@ -805,7 +656,6 @@ static void vmd_remove(struct pci_dev *dev)
> pci_stop_root_bus(vmd->bus);
> pci_remove_root_bus(vmd->bus);
> vmd_cleanup_srcu(vmd);
> - vmd_teardown_dma_ops(vmd);
> vmd_detach_resources(vmd);
> irq_domain_remove(vmd->irq_domain);
> }
> --
> 2.20.1
>
