This is the very basic SVM (shared virtual memory) support in XeKmd driver. SVM allows the programmer to use a shaed virtual address space between CPU program and GPU program. It abstracts away from the user the location of the backing memory in a mixed CPU and GPU programming environment. This work is based on previous I915 SVM implementation mainly from Niranjana Vishwanathapura and Oak Zeng, which has never been upstreamed before. This is our first attempt to upstream this work. This implementation depends on Linux kernel HMM support. See some key designs in patch #1. We are aware there are currently some effort to implement SVM using GMEM(generalized memory management, see https://lore.kernel.org/dri-devel/20231128125025.4449-1-weixi.zhu@xxxxxxxxxx/) We are open to this new method if it can be merged to upstream kernel. Before that, we think it is still safer to support SVM through HMM. This series only has basic SVM support. We think it is better to post this series earlier so we can get more eyes on it. Below are the works that is planned or ongoing: *Testing: We are working on the igt test right now. Some part of this series, especially the gpu page table update(patch #7, #8) and migration function (patch #10) need some debug to make it work. *Virtual address range based memory attributes and hints: We plan to expose uAPI for user to set memory attributes such as preferred location or migration granularity etc to a virtual address range. This is important to tune SVM performance. *GPU vram eviction: One key design choice of this series is, SVM layer allocate GPU memory directly from drm buddy allocator, instead of from xe vram manager. There is no BO (buffer object) concept in this implementation. The key benefit of this approach is we can migrate memory at page granularity easily. This also means SVM bypasses TTM's memory eviction logic. But we want the SVM memory and BO driver memory can mutually evicted each other. We have some prove of concept work to rework TTM resource manager for this purpose, see https://lore.kernel.org/dri-devel/20231102043306.2931989-1-oak.zeng@xxxxxxxxx/ We will continue work on that series then implement SVM's eviction function based on the concept of shared drm LRU list b/t SVM and TTM/BO driver. Oak Zeng (22): drm/xe/svm: Add SVM document drm/xe/svm: Add svm key data structures drm/xe/svm: create xe svm during vm creation drm/xe/svm: Trace svm creation drm/xe/svm: add helper to retrieve svm range from address drm/xe/svm: Introduce a helper to build sg table from hmm range drm/xe/svm: Add helper for binding hmm range to gpu drm/xe/svm: Add helper to invalidate svm range from GPU drm/xe/svm: Remap and provide memmap backing for GPU vram drm/xe/svm: Introduce svm migration function drm/xe/svm: implement functions to allocate and free device memory drm/xe/svm: Trace buddy block allocation and free drm/xe/svm: Handle CPU page fault drm/xe/svm: trace svm range migration drm/xe/svm: Implement functions to register and unregister mmu notifier drm/xe/svm: Implement the mmu notifier range invalidate callback drm/xe/svm: clean up svm range during process exit drm/xe/svm: Move a few structures to xe_gt.h drm/xe/svm: migrate svm range to vram drm/xe/svm: Populate svm range drm/xe/svm: GPU page fault support drm/xe/svm: Add DRM_XE_SVM kernel config entry Documentation/gpu/xe/index.rst | 1 + Documentation/gpu/xe/xe_svm.rst | 8 + drivers/gpu/drm/xe/Kconfig | 22 ++ drivers/gpu/drm/xe/Makefile | 5 + drivers/gpu/drm/xe/xe_device_types.h | 20 ++ drivers/gpu/drm/xe/xe_gt.h | 20 ++ drivers/gpu/drm/xe/xe_gt_pagefault.c | 28 +-- drivers/gpu/drm/xe/xe_migrate.c | 213 +++++++++++++++++ drivers/gpu/drm/xe/xe_migrate.h | 7 + drivers/gpu/drm/xe/xe_mmio.c | 12 + drivers/gpu/drm/xe/xe_pt.c | 134 ++++++++++- drivers/gpu/drm/xe/xe_pt.h | 5 + drivers/gpu/drm/xe/xe_svm.c | 324 +++++++++++++++++++++++++ drivers/gpu/drm/xe/xe_svm.h | 115 +++++++++ drivers/gpu/drm/xe/xe_svm_devmem.c | 232 ++++++++++++++++++ drivers/gpu/drm/xe/xe_svm_doc.h | 121 ++++++++++ drivers/gpu/drm/xe/xe_svm_migrate.c | 345 +++++++++++++++++++++++++++ drivers/gpu/drm/xe/xe_svm_range.c | 227 ++++++++++++++++++ drivers/gpu/drm/xe/xe_trace.h | 71 +++++- drivers/gpu/drm/xe/xe_vm.c | 7 + drivers/gpu/drm/xe/xe_vm_types.h | 12 + 21 files changed, 1904 insertions(+), 25 deletions(-) create mode 100644 Documentation/gpu/xe/xe_svm.rst create mode 100644 drivers/gpu/drm/xe/xe_svm.c create mode 100644 drivers/gpu/drm/xe/xe_svm.h create mode 100644 drivers/gpu/drm/xe/xe_svm_devmem.c create mode 100644 drivers/gpu/drm/xe/xe_svm_doc.h create mode 100644 drivers/gpu/drm/xe/xe_svm_migrate.c create mode 100644 drivers/gpu/drm/xe/xe_svm_range.c -- 2.26.3
