drm/xe: Use hmm_range_fault to populate user pages

This is an effort to unify hmmptr (aka system allocator)
and userptr code. hmm_range_fault is used to populate
a virtual address range for both hmmptr and userptr,
instead of hmmptr using hmm_range_fault and userptr
using get_user_pages_fast.

This also aligns with AMD gpu driver's behavior. In
long term, we plan to put some common helpers in this
area to drm layer so it can be re-used by different
vendors.

-v1
use the function with parameter to confirm whether lock is
acquired by the caller or needs to be acquired in hmm_range_fault.

Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Oak Zeng <oak.zeng@intel.com>
Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240412095237.1048599-3-himal.prasad.ghimiray@intel.com

diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 66b70fd..9c6f653 100644 (file)
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -39,6 +39,7 @@
 #include "xe_sync.h"
 #include "xe_trace.h"
 #include "xe_wa.h"
+#include "xe_hmm.h"
 
 static struct drm_gem_object *xe_vm_obj(struct xe_vm *vm)
 {
@@ -66,113 +67,14 @@ int xe_vma_userptr_check_repin(struct xe_userptr_vma *uvma)
 
 int xe_vma_userptr_pin_pages(struct xe_userptr_vma *uvma)
 {
-       struct xe_userptr *userptr = &uvma->userptr;
        struct xe_vma *vma = &uvma->vma;
        struct xe_vm *vm = xe_vma_vm(vma);
        struct xe_device *xe = vm->xe;
-       const unsigned long num_pages = xe_vma_size(vma) >> PAGE_SHIFT;
-       struct page **pages;
-       bool in_kthread = !current->mm;
-       unsigned long notifier_seq;
-       int pinned, ret, i;
-       bool read_only = xe_vma_read_only(vma);
 
        lockdep_assert_held(&vm->lock);
        xe_assert(xe, xe_vma_is_userptr(vma));
-retry:
-       if (vma->gpuva.flags & XE_VMA_DESTROYED)
-               return 0;
-
-       notifier_seq = mmu_interval_read_begin(&userptr->notifier);
-       if (notifier_seq == userptr->notifier_seq)
-               return 0;
-
-       pages = kvmalloc_array(num_pages, sizeof(*pages), GFP_KERNEL);
-       if (!pages)
-               return -ENOMEM;
-
-       if (userptr->sg) {
-               dma_unmap_sgtable(xe->drm.dev,
-                                 userptr->sg,
-                                 read_only ? DMA_TO_DEVICE :
-                                 DMA_BIDIRECTIONAL, 0);
-               sg_free_table(userptr->sg);
-               userptr->sg = NULL;
-       }
-
-       pinned = ret = 0;
-       if (in_kthread) {
-               if (!mmget_not_zero(userptr->notifier.mm)) {
-                       ret = -EFAULT;
-                       goto mm_closed;
-               }
-               kthread_use_mm(userptr->notifier.mm);
-       }
-
-       while (pinned < num_pages) {
-               ret = get_user_pages_fast(xe_vma_userptr(vma) +
-                                         pinned * PAGE_SIZE,
-                                         num_pages - pinned,
-                                         read_only ? 0 : FOLL_WRITE,
-                                         &pages[pinned]);
-               if (ret < 0)
-                       break;
-
-               pinned += ret;
-               ret = 0;
-       }
-
-       if (in_kthread) {
-               kthread_unuse_mm(userptr->notifier.mm);
-               mmput(userptr->notifier.mm);
-       }
-mm_closed:
-       if (ret)
-               goto out;
-
-       ret = sg_alloc_table_from_pages_segment(&userptr->sgt, pages,
-                                               pinned, 0,
-                                               (u64)pinned << PAGE_SHIFT,
-                                               xe_sg_segment_size(xe->drm.dev),
-                                               GFP_KERNEL);
-       if (ret) {
-               userptr->sg = NULL;
-               goto out;
-       }
-       userptr->sg = &userptr->sgt;
-
-       ret = dma_map_sgtable(xe->drm.dev, userptr->sg,
-                             read_only ? DMA_TO_DEVICE :
-                             DMA_BIDIRECTIONAL,
-                             DMA_ATTR_SKIP_CPU_SYNC |
-                             DMA_ATTR_NO_KERNEL_MAPPING);
-       if (ret) {
-               sg_free_table(userptr->sg);
-               userptr->sg = NULL;
-               goto out;
-       }
-
-       for (i = 0; i < pinned; ++i) {
-               if (!read_only) {
-                       lock_page(pages[i]);
-                       set_page_dirty(pages[i]);
-                       unlock_page(pages[i]);
-               }
 
-               mark_page_accessed(pages[i]);
-       }
-
-out:
-       release_pages(pages, pinned);
-       kvfree(pages);
-
-       if (!(ret < 0)) {
-               userptr->notifier_seq = notifier_seq;
-               if (xe_vma_userptr_check_repin(uvma) == -EAGAIN)
-                       goto retry;
-       }
-
-       return ret < 0 ? ret : 0;
+       return xe_hmm_userptr_populate_range(uvma, false);
 }
 
 static bool preempt_fences_waiting(struct xe_vm *vm)
@@ -956,8 +858,6 @@ static struct xe_vma *xe_vma_create(struct xe_vm *vm,
 static void xe_vma_destroy_late(struct xe_vma *vma)
 {
        struct xe_vm *vm = xe_vma_vm(vma);
-       struct xe_device *xe = vm->xe;
-       bool read_only = xe_vma_read_only(vma);
 
        if (vma->ufence) {
                xe_sync_ufence_put(vma->ufence);
@@ -965,16 +865,11 @@ static void xe_vma_destroy_late(struct xe_vma *vma)
        }
 
        if (xe_vma_is_userptr(vma)) {
-               struct xe_userptr *userptr = &to_userptr_vma(vma)->userptr;
+               struct xe_userptr_vma *uvma = to_userptr_vma(vma);
+               struct xe_userptr *userptr = &uvma->userptr;
 
-               if (userptr->sg) {
-                       dma_unmap_sgtable(xe->drm.dev,
-                                         userptr->sg,
-                                         read_only ? DMA_TO_DEVICE :
-                                         DMA_BIDIRECTIONAL, 0);
-                       sg_free_table(userptr->sg);
-                       userptr->sg = NULL;
-               }
+               if (userptr->sg)
+                       xe_hmm_userptr_free_sg(uvma);
 
                /*
                 * Since userptr pages are not pinned, we can't remove