[PATCH v3 3/6] drm/xe: Update xe_ttm_access_memory to use GPU for non-visible access
Thomas Hellström
thomas.hellstrom at linux.intel.com
Mon Oct 21 11:01:06 UTC 2024
On Mon, 2024-10-21 at 11:15 +0100, Matthew Auld wrote:
> On 19/10/2024 20:20, Matthew Brost wrote:
> > Add migrate layer functions to access VRAM and update
> > xe_ttm_access_memory to use for non-visible access.
> >
> > Signed-off-by: Matthew Brost <matthew.brost at intel.com>
>
> I guess this needs some IGTs? In i915 I think we have test_ptrace()
> in
> gem_mmap_offset.c, which could maybe be ported or something similar?
>
> > ---
> > drivers/gpu/drm/xe/xe_bo.c | 18 ++-
> > drivers/gpu/drm/xe/xe_migrate.c | 267
> > ++++++++++++++++++++++++++++++++
> > drivers/gpu/drm/xe/xe_migrate.h | 4 +
> > 3 files changed, 285 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/xe/xe_bo.c
> > b/drivers/gpu/drm/xe/xe_bo.c
> > index 99557af16120..0a7b91df69c2 100644
> > --- a/drivers/gpu/drm/xe/xe_bo.c
> > +++ b/drivers/gpu/drm/xe/xe_bo.c
> > @@ -1133,13 +1133,22 @@ static int xe_ttm_access_memory(struct
> > ttm_buffer_object *ttm_bo,
> > if (!mem_type_is_vram(ttm_bo->resource->mem_type))
> > return -EIO;
> >
> > - /* FIXME: Use GPU for non-visible VRAM */
> > - if (!xe_ttm_resource_visible(ttm_bo->resource))
> > - return -EIO;
> > -
> > if (!xe_pm_runtime_get_if_in_use(xe))
> > return -EIO;
I think we should be able to use a xe_pm_runtime_get() outside the bo
lock to avoid failing, right? That would require ttm_bo_vm_access() to
be used as a helper from within a xe_bo_vm_access(), though and the
above called replaced by xe_pm_runtime_get_noresume().
Is this called ever called from reclaim or dma-fence signalling?
/Thomas
> >
> > + if (!xe_ttm_resource_visible(ttm_bo->resource) || len >=
> > SZ_16K) {
>
> I guess commit message/title should be updated to mention that this
> also
> used for large accesses?
>
> > + struct xe_migrate *migrate =
> > + mem_type_to_migrate(xe, ttm_bo->resource-
> > >mem_type);
> > + int err;
> > +
> > + err = xe_migrate_access_memory(migrate, bo,
> > offset, buf, len,
> > + write);
> > + if (err)
> > + return err;
>
> Looks to be leaking the rpm ref here?
>
> > +
> > + goto out;
> > + }
> > +
> > vram = res_to_mem_region(ttm_bo->resource);
> > xe_res_first(ttm_bo->resource, offset & PAGE_MASK, bo-
> > >size, &cursor);
> >
> > @@ -1161,6 +1170,7 @@ static int xe_ttm_access_memory(struct
> > ttm_buffer_object *ttm_bo,
> > xe_res_next(&cursor, PAGE_SIZE);
> > } while (bytes_left);
> >
> > +out:
> > xe_pm_runtime_put(xe);
> >
> > return len;
> > diff --git a/drivers/gpu/drm/xe/xe_migrate.c
> > b/drivers/gpu/drm/xe/xe_migrate.c
> > index cfd31ae49cc1..ccdca1f79bb2 100644
> > --- a/drivers/gpu/drm/xe/xe_migrate.c
> > +++ b/drivers/gpu/drm/xe/xe_migrate.c
> > @@ -1542,6 +1542,273 @@ void xe_migrate_wait(struct xe_migrate *m)
> > dma_fence_wait(m->fence, false);
> > }
> >
> > +static u32 pte_update_cmd_size(u64 size)
> > +{
> > + u32 dword;
> > + u64 entries = DIV_ROUND_UP(size, XE_PAGE_SIZE);
> > +
> > + XE_WARN_ON(size > MAX_PREEMPTDISABLE_TRANSFER);
> > + /*
> > + * MI_STORE_DATA_IMM command is used to update page table.
> > Each
> > + * instruction can update maximumly 0x1ff pte entries. To
> > update
> > + * n (n <= 0x1ff) pte entries, we need:
> > + * 1 dword for the MI_STORE_DATA_IMM command header
> > (opcode etc)
> > + * 2 dword for the page table's physical location
> > + * 2*n dword for value of pte to fill (each pte entry is 2
> > dwords)
> > + */
> > + dword = (1 + 2) * DIV_ROUND_UP(entries, 0x1ff);
> > + dword += entries * 2;
> > +
> > + return dword;
> > +}
> > +
> > +static void build_pt_update_batch_sram(struct xe_migrate *m,
> > + struct xe_bb *bb, u32
> > pt_offset,
> > + dma_addr_t *sram_addr, u32
> > size)
> > +{
> > + u16 pat_index = tile_to_xe(m->tile)->pat.idx[XE_CACHE_WB];
> > + u32 ptes;
> > + int i = 0;
> > +
> > + ptes = DIV_ROUND_UP(size, XE_PAGE_SIZE);
> > + while (ptes) {
> > + u32 chunk = min(0x1ffU, ptes);
> > +
> > + bb->cs[bb->len++] = MI_STORE_DATA_IMM |
> > MI_SDI_NUM_QW(chunk);
> > + bb->cs[bb->len++] = pt_offset;
> > + bb->cs[bb->len++] = 0;
> > +
> > + pt_offset += chunk * 8;
> > + ptes -= chunk;
> > +
> > + while (chunk--) {
> > + u64 addr = sram_addr[i++] & PAGE_MASK;
> > +
> > + xe_tile_assert(m->tile, addr);
> > + addr = m->q->vm->pt_ops-
> > >pte_encode_addr(m->tile->xe,
> > +
> > addr, pat_index,
> > +
> > 0, false, 0);
> > + bb->cs[bb->len++] = lower_32_bits(addr);
> > + bb->cs[bb->len++] = upper_32_bits(addr);
> > + }
> > + }
> > +}
> > +
> > +enum xe_migrate_copy_dir {
> > + XE_MIGRATE_COPY_TO_VRAM,
> > + XE_MIGRATE_COPY_TO_SRAM,
> > +};
> > +
> > +static struct dma_fence *xe_migrate_vram(struct xe_migrate *m,
> > + unsigned long len,
> > + unsigned long
> > sram_offset,
> > + dma_addr_t *sram_addr,
> > u64 vram_addr,
> > + const enum
> > xe_migrate_copy_dir dir)
> > +{
> > + struct xe_gt *gt = m->tile->primary_gt;
> > + struct xe_device *xe = gt_to_xe(gt);
> > + struct dma_fence *fence = NULL;
> > + u32 batch_size = 2;
> > + u64 src_L0_ofs, dst_L0_ofs;
> > + struct xe_sched_job *job;
> > + struct xe_bb *bb;
> > + u32 update_idx, pt_slot = 0;
> > + unsigned long npages = DIV_ROUND_UP(len + sram_offset,
> > PAGE_SIZE);
> > + int err;
> > +
> > + xe_assert(xe, npages * PAGE_SIZE <=
> > MAX_PREEMPTDISABLE_TRANSFER);
> > +
> > + batch_size += pte_update_cmd_size(len);
> > + batch_size += EMIT_COPY_DW;
> > +
> > + bb = xe_bb_new(gt, batch_size, true);
> > + if (IS_ERR(bb)) {
> > + err = PTR_ERR(bb);
> > + return ERR_PTR(err);
> > + }
> > +
> > + build_pt_update_batch_sram(m, bb, pt_slot * XE_PAGE_SIZE,
> > + sram_addr, len + sram_offset);
> > +
> > + if (dir == XE_MIGRATE_COPY_TO_VRAM) {
> > + src_L0_ofs = xe_migrate_vm_addr(pt_slot, 0) +
> > sram_offset;
> > + dst_L0_ofs = xe_migrate_vram_ofs(xe, vram_addr,
> > false);
> > +
> > + } else {
> > + src_L0_ofs = xe_migrate_vram_ofs(xe, vram_addr,
> > false);
> > + dst_L0_ofs = xe_migrate_vm_addr(pt_slot, 0) +
> > sram_offset;
> > + }
> > +
> > + bb->cs[bb->len++] = MI_BATCH_BUFFER_END;
> > + update_idx = bb->len;
> > +
> > + emit_copy(gt, bb, src_L0_ofs, dst_L0_ofs, len,
> > XE_PAGE_SIZE);
> > +
> > + job = xe_bb_create_migration_job(m->q, bb,
> > + xe_migrate_batch_base(m,
> > true),
> > + update_idx);
> > + if (IS_ERR(job)) {
> > + err = PTR_ERR(job);
> > + goto err;
> > + }
> > +
> > + xe_sched_job_add_migrate_flush(job, 0);
> > +
> > + mutex_lock(&m->job_mutex);
> > + xe_sched_job_arm(job);
> > + fence = dma_fence_get(&job->drm.s_fence->finished);
> > + xe_sched_job_push(job);
> > +
> > + dma_fence_put(m->fence);
> > + m->fence = dma_fence_get(fence);
> > + mutex_unlock(&m->job_mutex);
> > +
> > + xe_bb_free(bb, fence);
> > +
> > + return fence;
> > +
> > +err:
> > + xe_bb_free(bb, NULL);
> > +
> > + return ERR_PTR(err);
> > +}
> > +
> > +static void xe_migrate_dma_unmap(struct xe_device *xe, dma_addr_t
> > *dma_addr,
> > + int len, int write)
> > +{
> > + unsigned long i, npages = DIV_ROUND_UP(len, PAGE_SIZE);
> > +
> > + for (i = 0; i < npages; ++i) {
> > + if (!dma_addr[i])
> > + continue;
> > +
> > + dma_unmap_page(xe->drm.dev, dma_addr[i],
> > PAGE_SIZE,
> > + write ? DMA_TO_DEVICE :
> > DMA_FROM_DEVICE);
> > + }
> > + kfree(dma_addr);
> > +}
> > +
> > +static dma_addr_t *xe_migrate_dma_map(struct xe_device *xe,
> > + void *buf, int len, int
> > write)
> > +{
> > + dma_addr_t *dma_addr;
> > + unsigned long i, npages = DIV_ROUND_UP(len, PAGE_SIZE);
> > +
> > + dma_addr = kcalloc(npages, sizeof(*dma_addr), GFP_KERNEL);
> > + if (!dma_addr)
> > + return ERR_PTR(-ENOMEM);
> > +
> > + for (i = 0; i < npages; ++i) {
> > + dma_addr_t addr;
> > + struct page *page;
> > +
> > + if (is_vmalloc_addr(buf))
> > + page = vmalloc_to_page(buf);
> > + else
> > + page = virt_to_page(buf);
> > +
> > + addr = dma_map_page(xe->drm.dev,
> > + page, 0, PAGE_SIZE,
> > + write ? DMA_TO_DEVICE :
> > + DMA_FROM_DEVICE);
> > + if (dma_mapping_error(xe->drm.dev, addr))
> > + goto err_fault;
> > +
> > + dma_addr[i] = addr;
> > + buf += PAGE_SIZE;
> > + }
> > +
> > + return dma_addr;
> > +
> > +err_fault:
> > + xe_migrate_dma_unmap(xe, dma_addr, len, write);
> > + return ERR_PTR(-EFAULT);
> > +}
> > +
> > +/**
> > + * xe_migrate_access_memory - Access memory of a BO via GPU
> > + *
> > + * @m: The migration context.
> > + * @bo: buffer object
> > + * @offset: access offset into buffer object
> > + * @buf: pointer to caller memory to read into or write from
> > + * @len: length of access
> > + * @write: write access
> > + *
> > + * Access memory of a BO via GPU either reading in or writing from
> > a passed in
> > + * pointer. Pointer is dma mapped for GPU access and GPU commands
> > are issued to
> > + * read to or write from pointer.
> > + *
> > + * Returns:
> > + * 0 if successful, negative error code on failure.
> > + */
> > +int xe_migrate_access_memory(struct xe_migrate *m, struct xe_bo
> > *bo,
> > + unsigned long offset, void *buf, int
> > len,
> > + int write)
> > +{
> > + struct xe_tile *tile = m->tile;
> > + struct xe_device *xe = tile_to_xe(tile);
> > + struct xe_res_cursor cursor;
> > + struct dma_fence *fence = NULL;
> > + dma_addr_t *dma_addr;
> > + unsigned long page_offset = (unsigned long)buf &
> > ~PAGE_MASK;
> > + int bytes_left = len, current_page = 0;
> > +
> > + xe_bo_assert_held(bo);
> > +
> > + dma_addr = xe_migrate_dma_map(xe, buf, len + page_offset,
> > write);
> > + if (IS_ERR(dma_addr))
> > + return PTR_ERR(dma_addr);
> > +
> > + xe_res_first(bo->ttm.resource, offset, bo->size, &cursor);
> > +
> > + do {
> > + struct dma_fence *__fence;
> > + u64 vram_addr = vram_region_gpu_offset(bo-
> > >ttm.resource) +
> > + cursor.start;
> > + int current_bytes;
> > +
> > + if (cursor.size > MAX_PREEMPTDISABLE_TRANSFER)
> > + current_bytes = min_t(int, bytes_left,
> > +
> > MAX_PREEMPTDISABLE_TRANSFER);
> > + else
> > + current_bytes = min_t(int, bytes_left,
> > cursor.size);
> > +
> > + if (fence)
> > + dma_fence_put(fence);
> > +
> > + __fence = xe_migrate_vram(m, current_bytes,
> > + (unsigned long)buf &
> > ~PAGE_MASK,
> > + dma_addr + current_page,
> > + vram_addr, write ?
> > + XE_MIGRATE_COPY_TO_VRAM
> > :
> > +
> > XE_MIGRATE_COPY_TO_SRAM);
> > + if (IS_ERR(__fence)) {
> > + if (fence)
> > + dma_fence_wait(fence, false);
> > + fence = __fence;
> > + goto out_err;
> > + }
> > + fence = __fence;
> > +
> > + buf += current_bytes;
> > + offset += current_bytes;
> > + current_page += DIV_ROUND_UP(current_bytes,
> > PAGE_SIZE);
> > + bytes_left -= current_bytes;
> > + if (bytes_left)
> > + xe_res_next(&cursor, current_bytes);
> > + } while (bytes_left);
> > +
> > + dma_fence_wait(fence, false);
> > + xe_migrate_dma_unmap(xe, dma_addr, len + page_offset,
> > write);
> > +
> > + return 0;
> > +
> > +out_err:
> > + xe_migrate_dma_unmap(xe, dma_addr, len + page_offset,
> > write);
> > + return PTR_ERR(fence);
> > +}
> > +
> > #if IS_ENABLED(CONFIG_DRM_XE_KUNIT_TEST)
> > #include "tests/xe_migrate.c"
> > #endif
> > diff --git a/drivers/gpu/drm/xe/xe_migrate.h
> > b/drivers/gpu/drm/xe/xe_migrate.h
> > index 0109866e398a..94197d262178 100644
> > --- a/drivers/gpu/drm/xe/xe_migrate.h
> > +++ b/drivers/gpu/drm/xe/xe_migrate.h
> > @@ -102,6 +102,10 @@ struct dma_fence *xe_migrate_copy(struct
> > xe_migrate *m,
> > struct ttm_resource *dst,
> > bool copy_only_ccs);
> >
> > +int xe_migrate_access_memory(struct xe_migrate *m, struct xe_bo
> > *bo,
> > + unsigned long offset, void *buf, int
> > len,
> > + int write);
> > +
> > #define XE_MIGRATE_CLEAR_FLAG_BO_DATA BIT(0)
> > #define XE_MIGRATE_CLEAR_FLAG_CCS_DATA BIT(1)
> > #define
> > XE_MIGRATE_CLEAR_FLAG_FULL (XE_MIGRATE_CLEAR_FLAG_BO_DATA | \
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