This patch is Reviewed-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
Regards,
Felix
On 3/12/2019 9:17 PM, Yang, Philip wrote:
> userptr may cross two VMAs if the forked child process (not call exec
> after fork) malloc buffer, then free it, and then malloc larger size
> buf, kerenl will create new VMA adjacent to old VMA which was cloned
> from parent process, some pages of userptr are in the first VMA, the
> rest pages are in the second VMA.
>
> HMM expects range only have one VMA, loop over all VMAs in the address
> range, create multiple ranges to handle this case. See
> is_mergeable_anon_vma in mm/mmap.c for details.
>
> Change-Id: I0ca8c77e28deabccc139906f9ffee04b7e383314
> Signed-off-by: Philip Yang <Philip.Yang@xxxxxxx>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 126 +++++++++++++++++-------
> 1 file changed, 91 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index c1240bf243ba..c14198737dcd 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -711,7 +711,8 @@ struct amdgpu_ttm_tt {
> struct task_struct *usertask;
> uint32_t userflags;
> #if IS_ENABLED(CONFIG_DRM_AMDGPU_USERPTR)
> - struct hmm_range range;
> + struct hmm_range *ranges;
> + int nr_ranges;
> #endif
> };
>
> @@ -723,62 +724,108 @@ struct amdgpu_ttm_tt {
> * once afterwards to stop HMM tracking
> */
> #if IS_ENABLED(CONFIG_DRM_AMDGPU_USERPTR)
> +
> +/* Support Userptr pages cross max 16 vmas */
> +#define MAX_NR_VMAS (16)
> +
> int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
> {
> struct amdgpu_ttm_tt *gtt = (void *)ttm;
> struct mm_struct *mm = gtt->usertask->mm;
> - unsigned long end = gtt->userptr + ttm->num_pages * PAGE_SIZE;
> - struct hmm_range *range = >t->range;
> - int r = 0, i;
> + unsigned long start = gtt->userptr;
> + unsigned long end = start + ttm->num_pages * PAGE_SIZE;
> + struct hmm_range *ranges;
> + struct vm_area_struct *vma = NULL, *vmas[MAX_NR_VMAS];
> + uint64_t *pfns, f;
> + int r = 0, i, nr_pages;
>
> if (!mm) /* Happens during process shutdown */
> return -ESRCH;
>
> - amdgpu_hmm_init_range(range);
> -
> down_read(&mm->mmap_sem);
>
> - range->vma = find_vma(mm, gtt->userptr);
> - if (!range_in_vma(range->vma, gtt->userptr, end))
> - r = -EFAULT;
> - else if ((gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) &&
> - range->vma->vm_file)
> + /* user pages may cross multiple VMAs */
> + gtt->nr_ranges = 0;
> + do {
> + unsigned long vm_start;
> +
> + if (gtt->nr_ranges >= MAX_NR_VMAS) {
> + DRM_ERROR("Too many VMAs in userptr range\n");
> + r = -EFAULT;
> + goto out;
> + }
> +
> + vm_start = vma ? vma->vm_end : start;
> + vma = find_vma(mm, vm_start);
> + if (unlikely(!vma || vm_start < vma->vm_start)) {
> + r = -EFAULT;
> + goto out;
> + }
> + vmas[gtt->nr_ranges++] = vma;
> + } while (end > vma->vm_end);
> +
> + DRM_DEBUG_DRIVER("0x%lx nr_ranges %d pages 0x%lx\n",
> + start, gtt->nr_ranges, ttm->num_pages);
> +
> + if (unlikely((gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) &&
> + vmas[0]->vm_file)) {
> r = -EPERM;
> - if (r)
> goto out;
> + }
>
> - range->pfns = kvmalloc_array(ttm->num_pages, sizeof(uint64_t),
> - GFP_KERNEL);
> - if (range->pfns == NULL) {
> + ranges = kvmalloc_array(gtt->nr_ranges, sizeof(*ranges), GFP_KERNEL);
> + if (unlikely(!ranges)) {
> r = -ENOMEM;
> goto out;
> }
> - range->start = gtt->userptr;
> - range->end = end;
>
> - range->pfns[0] = range->flags[HMM_PFN_VALID];
> - range->pfns[0] |= amdgpu_ttm_tt_is_readonly(ttm) ?
> - 0 : range->flags[HMM_PFN_WRITE];
> - for (i = 1; i < ttm->num_pages; i++)
> - range->pfns[i] = range->pfns[0];
> + pfns = kvmalloc_array(ttm->num_pages, sizeof(*pfns), GFP_KERNEL);
> + if (unlikely(!pfns)) {
> + r = -ENOMEM;
> + goto out_free_ranges;
> + }
> +
> + for (i = 0; i < gtt->nr_ranges; i++)
> + amdgpu_hmm_init_range(&ranges[i]);
> +
> + f = ranges[0].flags[HMM_PFN_VALID];
> + f |= amdgpu_ttm_tt_is_readonly(ttm) ?
> + 0 : ranges[0].flags[HMM_PFN_WRITE];
> + memset64(pfns, f, ttm->num_pages);
> +
> + for (nr_pages = 0, i = 0; i < gtt->nr_ranges; i++) {
> + ranges[i].vma = vmas[i];
> + ranges[i].start = max(start, vmas[i]->vm_start);
> + ranges[i].end = min(end, vmas[i]->vm_end);
> + ranges[i].pfns = pfns + nr_pages;
> + nr_pages += (ranges[i].end - ranges[i].start) / PAGE_SIZE;
> +
> + r = hmm_vma_fault(&ranges[i], true);
> + if (unlikely(r))
> + break;
> + }
> + if (unlikely(r)) {
> + while (i--)
> + hmm_vma_range_done(&ranges[i]);
>
> - /* This may trigger page table update */
> - r = hmm_vma_fault(range, true);
> - if (r)
> goto out_free_pfns;
> + }
>
> up_read(&mm->mmap_sem);
>
> for (i = 0; i < ttm->num_pages; i++)
> - pages[i] = hmm_pfn_to_page(range, range->pfns[i]);
> + pages[i] = hmm_pfn_to_page(&ranges[0], pfns[i]);
> + gtt->ranges = ranges;
>
> return 0;
>
> out_free_pfns:
> - kvfree(range->pfns);
> - range->pfns = NULL;
> + kvfree(pfns);
> +out_free_ranges:
> + kvfree(ranges);
> out:
> up_read(&mm->mmap_sem);
> +
> return r;
> }
>
> @@ -792,15 +839,23 @@ bool amdgpu_ttm_tt_get_user_pages_done(struct ttm_tt *ttm)
> {
> struct amdgpu_ttm_tt *gtt = (void *)ttm;
> bool r = false;
> + int i;
>
> if (!gtt || !gtt->userptr)
> return false;
>
> - WARN_ONCE(!gtt->range.pfns, "No user pages to check\n");
> - if (gtt->range.pfns) {
> - r = hmm_vma_range_done(>t->range);
> - kvfree(gtt->range.pfns);
> - gtt->range.pfns = NULL;
> + DRM_DEBUG_DRIVER("user_pages_done 0x%llx nr_ranges %d pages 0x%lx\n",
> + gtt->userptr, gtt->nr_ranges, ttm->num_pages);
> +
> + WARN_ONCE(!gtt->ranges || !gtt->ranges[0].pfns,
> + "No user pages to check\n");
> +
> + if (gtt->ranges) {
> + for (i = 0; i < gtt->nr_ranges; i++)
> + r |= hmm_vma_range_done(>t->ranges[i]);
> + kvfree(gtt->ranges[0].pfns);
> + kvfree(gtt->ranges);
> + gtt->ranges = NULL;
> }
>
> return r;
> @@ -884,8 +939,9 @@ static void amdgpu_ttm_tt_unpin_userptr(struct ttm_tt *ttm)
> sg_free_table(ttm->sg);
>
> #if IS_ENABLED(CONFIG_DRM_AMDGPU_USERPTR)
> - if (gtt->range.pfns &&
> - ttm->pages[0] == hmm_pfn_to_page(>t->range, gtt->range.pfns[0]))
> + if (gtt->ranges &&
> + ttm->pages[0] == hmm_pfn_to_page(>t->ranges[0],
> + gtt->ranges[0].pfns[0]))
> WARN_ONCE(1, "Missing get_user_page_done\n");
> #endif
> }
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