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This patch introduces a new UIO driver, uio_pci_generic_sva, which extends the functionality of uio_pci_generic by adding support for Shared Virtual Addressing (SVA) when IOMMU is enabled in the system. The key enhancement allows PCI devices to directly use user-space virtual addresses for DMA operations, eliminating the need for bounce buffers or explicit IOVA mapping. This is achieved by leveraging the kernel's IOMMU-SVA subsystem, including process address space attachment, page fault handling, and shared context management between CPU and device. With this driver, userspace applications can perform zero-copy DMA using native pointers: void *addr = malloc(N); set_dma_addr((uint64_t)addr); // Passing user VA directly start_dma(); The device can now access 'addr' through the IOMMU's PASID-based translation, provided that the underlying IOMMU hardware (e.g., Intel VT-d 3.1+, AMD-Vi, ARM SMMU, RISCV IOMMU) and platform support SVA. Dependencies: - CONFIG_IOMMU_SVA must be enabled. - The platform must support PRI (Page Request Interface) and PASID. - Device drivers/userspace must handle page faults if demand-paging is used. The implementation reuses core logic from uio_pci_generic.c while adding PASID setting, and integration with the IOMMU SVA APIs. Also, add a read-only sysfs attribute 'pasid' to expose the Process Address Space ID assigned by IOMMU driver when binding an SVA-enabled device. For details, refer to the ABI documentation for uio_pci_sva driver sysfs attribute (Documentation/ABI/testing/sysfs-driver-uio_pci_sva-pasid). Signed-off-by: Yaxing Guo <guoyaxing@bosc.ac.cn> Link: https://patch.msgid.link/20250926095828.506-1-guoyaxing@bosc.ac.cn Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| .. | ||
| Kconfig | ||
| Makefile | ||
| uio.c | ||
| uio_aec.c | ||
| uio_cif.c | ||
| uio_dfl.c | ||
| uio_dmem_genirq.c | ||
| uio_fsl_elbc_gpcm.c | ||
| uio_hv_generic.c | ||
| uio_mf624.c | ||
| uio_netx.c | ||
| uio_pci_generic.c | ||
| uio_pci_generic_sva.c | ||
| uio_pdrv_genirq.c | ||
| uio_sercos3.c | ||