[PATCH] drm/amdgpu: handle userptr corner cases with HMM path
Kuehling, Felix
Felix.Kuehling at amd.com
Sat Mar 2 00:46:35 UTC 2019
Since you're addressing two distinct bugs, please split this into two patches.
For the multiple VMAs, should we generalize that to handle any number of VMAs? It's not a typical case, but you could easily construct situations with mprotect where different parts of the same buffer have different VMAs and then register that as a single user pointer. Or you could user MAP_FIXED to map multiple files to adjacent virtual addresses.
There may be two ways to handle this:
1. If the userptr address range spans more than one VMA, fail
2. Loop over all the VMAs in the address range
Thanks,
Felix
-----Original Message-----
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Yang, Philip
Sent: Friday, March 01, 2019 12:30 PM
To: amd-gfx at lists.freedesktop.org
Cc: Yang, Philip <Philip.Yang at amd.com>
Subject: [PATCH] drm/amdgpu: handle userptr corner cases with HMM path
Those corner cases are found by kfdtest.KFDIPCTest.
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,
we have to use two ranges to handle this case. See is_mergeable_anon_vma
in mm/mmap.c for details.
kfd userptr restore may have concurrent userptr invalidation, reschedule
to restore and then needs call hmm_vma_range_done to remove range from
hmm->ranges list, otherwise hmm_vma_fault add same range to the list
will cause loop in the list because range->next point to range itself.
Change-Id: I641ba7406c32bd8b7ae715f52bd896d53fe56801
Signed-off-by: Philip Yang <Philip.Yang at amd.com>
---
.../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 28 +++++--
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 73 +++++++++++++------
2 files changed, 71 insertions(+), 30 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index f8104760f1e6..179af9d3ab19 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -1738,6 +1738,23 @@ static int update_invalid_user_pages(struct amdkfd_process_info *process_info,
return 0;
}
+/* Untrack invalid userptr BOs
+ *
+ * Stop HMM track the userptr update
+ */
+static void untrack_invalid_user_pages(struct amdkfd_process_info *process_info)
+{
+ struct kgd_mem *mem, *tmp_mem;
+ struct amdgpu_bo *bo;
+
+ list_for_each_entry_safe(mem, tmp_mem,
+ &process_info->userptr_inval_list,
+ validate_list.head) {
+ bo = mem->bo;
+ amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
+ }
+}
+
/* Validate invalid userptr BOs
*
* Validates BOs on the userptr_inval_list, and moves them back to the
@@ -1855,12 +1872,7 @@ static int validate_invalid_user_pages(struct amdkfd_process_info *process_info)
out_free:
kfree(pd_bo_list_entries);
out_no_mem:
- list_for_each_entry_safe(mem, tmp_mem,
- &process_info->userptr_inval_list,
- validate_list.head) {
- bo = mem->bo;
- amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
- }
+ untrack_invalid_user_pages(process_info);
return ret;
}
@@ -1904,8 +1916,10 @@ static void amdgpu_amdkfd_restore_userptr_worker(struct work_struct *work)
* and we can just restart the queues.
*/
if (!list_empty(&process_info->userptr_inval_list)) {
- if (atomic_read(&process_info->evicted_bos) != evicted_bos)
+ if (atomic_read(&process_info->evicted_bos) != evicted_bos) {
+ untrack_invalid_user_pages(process_info);
goto unlock_out; /* Concurrent eviction, try again */
+ }
if (validate_invalid_user_pages(process_info))
goto unlock_out;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index cd0ccfbbcb84..e5736225f513 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -711,7 +711,7 @@ 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 range, range2;
#endif
};
@@ -727,58 +727,81 @@ 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;
+ unsigned long start = gtt->userptr;
+ unsigned long end = start + ttm->num_pages * PAGE_SIZE;
struct hmm_range *range = >t->range;
+ struct hmm_range *range2 = >t->range2;
+ struct vm_area_struct *vma, *vma_next = NULL;
+ uint64_t *pfns, f;
int r = 0, i;
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 vma bound */
+ vma = find_vma(mm, start);
+ if (unlikely(!range_in_vma(vma, start, end))) {
+ vma_next = find_extend_vma(mm, end);
+ if (unlikely(!vma_next)) {
+ r = -EFAULT;
+ goto out;
+ }
+ amdgpu_hmm_init_range(range2);
+ }
+ amdgpu_hmm_init_range(range);
+
+ if (unlikely((gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) &&
+ vma->vm_file)) {
r = -EPERM;
- if (r)
goto out;
+ }
- range->pfns = kvmalloc_array(ttm->num_pages, sizeof(uint64_t),
- GFP_KERNEL);
- if (range->pfns == NULL) {
+ pfns = kvmalloc_array(ttm->num_pages, sizeof(uint64_t), GFP_KERNEL);
+ if (unlikely(!pfns)) {
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];
+ f = range->flags[HMM_PFN_VALID];
+ f |= amdgpu_ttm_tt_is_readonly(ttm) ? 0 : range->flags[HMM_PFN_WRITE];
+ memset64(pfns, f, ttm->num_pages);
+ range->pfns = pfns;
+ range->vma = vma;
+ range->start = start;
+ range->end = min(end, vma->vm_end);
/* This may trigger page table update */
r = hmm_vma_fault(range, true);
- if (r)
+ if (unlikely(r))
goto out_free_pfns;
+ if (unlikely(vma_next)) {
+ range2->pfns = pfns + (range->end - range->start) / PAGE_SIZE;
+ range2->vma = vma_next;
+ range2->start = range->end;
+ range2->end = end;
+ r = hmm_vma_fault(range2, true);
+ if (unlikely(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(range, pfns[i]);
return 0;
out_free_pfns:
- kvfree(range->pfns);
+ kvfree(pfns);
range->pfns = NULL;
+ if (unlikely(vma_next))
+ range2->pfns = NULL;
out:
up_read(&mm->mmap_sem);
+
return r;
}
@@ -802,6 +825,10 @@ bool amdgpu_ttm_tt_get_user_pages_done(struct ttm_tt *ttm)
kvfree(gtt->range.pfns);
gtt->range.pfns = NULL;
}
+ if (gtt->range2.pfns) {
+ r = hmm_vma_range_done(>t->range2);
+ gtt->range2.pfns = NULL;
+ }
return r;
}
--
2.17.1
_______________________________________________
amd-gfx mailing list
amd-gfx at lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
More information about the amd-gfx
mailing list