mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-18 00:26:47 +07:00
cf4ee73fd9
The implementation of current kvmgt implicitly setup dma mapping at MPT API gfn_to_mfn. First this design against the API's original purpose. Second, there is no unmap hit in this design. The result is that the dma mapping keep growing larger and larger. For mutl-vm case, they will consume IOMMU IOVA low 4GB address space quickly and so tons of rbtree entries crated in the IOMMU IOVA allocator. Finally, single IOVA allocation can take as long as ~70ms. Such latency is intolerable. To address both above issues, this patch introduced two new MPT API: o dma_map_guest_page - setup dma map for guest page o dma_unmap_guest_page - cancel dma map for guest page The kvmgt implements these 2 API. And to reduce dma setup overhead for duplicated pages (eg. scratch pages), two caches are used: one is for mapping gfn to struct gvt_dma, another is for mapping dma addr to struct gvt_dma. With these 2 new API, the gtt now is able to cancel dma mapping when page table is invalidated. The dma mapping is not in a gradual increase now. v2: follow the old logic for VFIO_IOMMU_NOTIFY_DMA_UNMAP at this point. Cc: Hang Yuan <hang.yuan@intel.com> Cc: Xiong Zhang <xiong.y.zhang@intel.com> Signed-off-by: Changbin Du <changbin.du@intel.com> Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.