On Wed, Jun 11, 2014 at 12:59:51PM +0100, Chris Wilson wrote:
> Currently objects for which the hardware needs a contiguous physical
> address are allocated a shadow backing storage to satisfy the contraint.
> This shadow buffer is not wired into the normal obj->pages and so the
> physical object is incoherent with accesses via the GPU, GTT and CPU. By
> setting up the appropriate scatter-gather table, we can allow userspace
> to access the physical object via either a GTT mmaping of or by rendering
> into the GEM bo. However, keeping the CPU mmap of the shmemfs backing
> storage coherent with the contiguous shadow is not yet possible.
> Fortuituously, CPU mmaps of objects requiring physical addresses are not
> expected to be coherent anyway.
>
> This allows the physical constraint of the GEM object to be transparent
> to userspace and allow it to efficiently render into or update them via
> the GTT and GPU.
>
> v2: Fix leak of pci handle spotted by Ville
> v3: Remove the now duplicate call to detach_phys_object during free.
> v4: Wait for rendering before pwrite. As this patch makes it possible to
> render into the phys object, we should make it correct as well!
>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
So for the record I'd like to see a test for the wait_rendering in
phys_pwrite:
a) show black screen with black cursor
b) throw busy load on blitter
c) upload white cursor with blitter
d) pwrite black cursor
e) wait for blitter to finish
grab crc for a&e and compare
-Daniel
> ---
> drivers/gpu/drm/i915/i915_dma.c | 3 +
> drivers/gpu/drm/i915/i915_drv.h | 6 +-
> drivers/gpu/drm/i915/i915_gem.c | 206 +++++++++++++++++++++++++++-------------
> include/uapi/drm/i915_drm.h | 1 +
> 4 files changed, 149 insertions(+), 67 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index 59e8ffe230a7..b1f072039865 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -1025,6 +1025,9 @@ static int i915_getparam(struct drm_device *dev, void *data,
> case I915_PARAM_CMD_PARSER_VERSION:
> value = i915_cmd_parser_get_version();
> break;
> + case I915_PARAM_HAS_COHERENT_PHYS_GTT:
> + value = 1;
> + break;
> default:
> DRM_DEBUG("Unknown parameter %d\n", param->param);
> return -EINVAL;
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 0a9d1b85d529..c80ddcf8aa6f 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1715,10 +1715,10 @@ struct drm_i915_gem_object {
> unsigned long user_pin_count;
> struct drm_file *pin_filp;
>
> - /** for phy allocated objects */
> - drm_dma_handle_t *phys_handle;
> -
> union {
> + /** for phy allocated objects */
> + drm_dma_handle_t *phys_handle;
> +
> struct i915_gem_userptr {
> uintptr_t ptr;
> unsigned read_only :1;
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 25b5063388b2..f9e158261c42 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -209,40 +209,137 @@ i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,
> return 0;
> }
>
> -static void i915_gem_object_detach_phys(struct drm_i915_gem_object *obj)
> +static int
> +i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
> {
> - drm_dma_handle_t *phys = obj->phys_handle;
> + struct address_space *mapping = file_inode(obj->base.filp)->i_mapping;
> + char *vaddr = obj->phys_handle->vaddr;
> + struct sg_table *st;
> + struct scatterlist *sg;
> + int i;
>
> - if (!phys)
> - return;
> + if (WARN_ON(i915_gem_object_needs_bit17_swizzle(obj)))
> + return -EINVAL;
> +
> + for (i = 0; i < obj->base.size / PAGE_SIZE; i++) {
> + struct page *page;
> + char *src;
> +
> + page = shmem_read_mapping_page(mapping, i);
> + if (IS_ERR(page))
> + return PTR_ERR(page);
> +
> + src = kmap_atomic(page);
> + memcpy(vaddr, src, PAGE_SIZE);
> + drm_clflush_virt_range(vaddr, PAGE_SIZE);
> + kunmap_atomic(src);
> +
> + page_cache_release(page);
> + vaddr += PAGE_SIZE;
> + }
> +
> + i915_gem_chipset_flush(obj->base.dev);
> +
> + st = kmalloc(sizeof(*st), GFP_KERNEL);
> + if (st == NULL)
> + return -ENOMEM;
> +
> + if (sg_alloc_table(st, 1, GFP_KERNEL)) {
> + kfree(st);
> + return -ENOMEM;
> + }
> +
> + sg = st->sgl;
> + sg->offset = 0;
> + sg->length = obj->base.size;
>
> - if (obj->madv == I915_MADV_WILLNEED) {
> + sg_dma_address(sg) = obj->phys_handle->busaddr;
> + sg_dma_len(sg) = obj->base.size;
> +
> + obj->pages = st;
> + obj->has_dma_mapping = true;
> + return 0;
> +}
> +
> +static void
> +i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj)
> +{
> + int ret;
> +
> + BUG_ON(obj->madv == __I915_MADV_PURGED);
> +
> + ret = i915_gem_object_set_to_cpu_domain(obj, true);
> + if (ret) {
> + /* In the event of a disaster, abandon all caches and
> + * hope for the best.
> + */
> + WARN_ON(ret != -EIO);
> + obj->base.read_domains = obj->base.write_domain = I915_GEM_DOMAIN_CPU;
> + }
> +
> + if (obj->madv == I915_MADV_DONTNEED)
> + obj->dirty = 0;
> +
> + if (obj->dirty) {
> struct address_space *mapping = file_inode(obj->base.filp)->i_mapping;
> - char *vaddr = phys->vaddr;
> + char *vaddr = obj->phys_handle->vaddr;
> int i;
>
> for (i = 0; i < obj->base.size / PAGE_SIZE; i++) {
> - struct page *page = shmem_read_mapping_page(mapping, i);
> - if (!IS_ERR(page)) {
> - char *dst = kmap_atomic(page);
> - memcpy(dst, vaddr, PAGE_SIZE);
> - drm_clflush_virt_range(dst, PAGE_SIZE);
> - kunmap_atomic(dst);
> -
> - set_page_dirty(page);
> + struct page *page;
> + char *dst;
> +
> + page = shmem_read_mapping_page(mapping, i);
> + if (IS_ERR(page))
> + continue;
> +
> + dst = kmap_atomic(page);
> + drm_clflush_virt_range(vaddr, PAGE_SIZE);
> + memcpy(dst, vaddr, PAGE_SIZE);
> + kunmap_atomic(dst);
> +
> + set_page_dirty(page);
> + if (obj->madv == I915_MADV_WILLNEED)
> mark_page_accessed(page);
> - page_cache_release(page);
> - }
> + page_cache_release(page);
> vaddr += PAGE_SIZE;
> }
> - i915_gem_chipset_flush(obj->base.dev);
> + obj->dirty = 0;
> }
>
> -#ifdef CONFIG_X86
> - set_memory_wb((unsigned long)phys->vaddr, phys->size / PAGE_SIZE);
> -#endif
> - drm_pci_free(obj->base.dev, phys);
> - obj->phys_handle = NULL;
> + sg_free_table(obj->pages);
> + kfree(obj->pages);
> +
> + obj->has_dma_mapping = false;
> +}
> +
> +static void
> +i915_gem_object_release_phys(struct drm_i915_gem_object *obj)
> +{
> + drm_pci_free(obj->base.dev, obj->phys_handle);
> +}
> +
> +static const struct drm_i915_gem_object_ops i915_gem_phys_ops = {
> + .get_pages = i915_gem_object_get_pages_phys,
> + .put_pages = i915_gem_object_put_pages_phys,
> + .release = i915_gem_object_release_phys,
> +};
> +
> +static int
> +drop_pages(struct drm_i915_gem_object *obj)
> +{
> + struct i915_vma *vma, *next;
> + int ret;
> +
> + drm_gem_object_reference(&obj->base);
> + list_for_each_entry_safe(vma, next, &obj->vma_list, vma_link)
> + if (i915_vma_unbind(vma))
> + break;
> +
> + ret = i915_gem_object_put_pages(obj);
> + drm_gem_object_unreference(&obj->base);
> +
> + return ret;
> }
>
> int
> @@ -250,9 +347,7 @@ i915_gem_object_attach_phys(struct drm_i915_gem_object *obj,
> int align)
> {
> drm_dma_handle_t *phys;
> - struct address_space *mapping;
> - char *vaddr;
> - int i;
> + int ret;
>
> if (obj->phys_handle) {
> if ((unsigned long)obj->phys_handle->vaddr & (align -1))
> @@ -267,41 +362,19 @@ i915_gem_object_attach_phys(struct drm_i915_gem_object *obj,
> if (obj->base.filp == NULL)
> return -EINVAL;
>
> + ret = drop_pages(obj);
> + if (ret)
> + return ret;
> +
> /* create a new object */
> phys = drm_pci_alloc(obj->base.dev, obj->base.size, align);
> if (!phys)
> return -ENOMEM;
>
> - vaddr = phys->vaddr;
> -#ifdef CONFIG_X86
> - set_memory_wc((unsigned long)vaddr, phys->size / PAGE_SIZE);
> -#endif
> - mapping = file_inode(obj->base.filp)->i_mapping;
> - for (i = 0; i < obj->base.size / PAGE_SIZE; i++) {
> - struct page *page;
> - char *src;
> -
> - page = shmem_read_mapping_page(mapping, i);
> - if (IS_ERR(page)) {
> -#ifdef CONFIG_X86
> - set_memory_wb((unsigned long)phys->vaddr, phys->size / PAGE_SIZE);
> -#endif
> - drm_pci_free(obj->base.dev, phys);
> - return PTR_ERR(page);
> - }
> -
> - src = kmap_atomic(page);
> - memcpy(vaddr, src, PAGE_SIZE);
> - kunmap_atomic(src);
> -
> - mark_page_accessed(page);
> - page_cache_release(page);
> -
> - vaddr += PAGE_SIZE;
> - }
> -
> obj->phys_handle = phys;
> - return 0;
> + obj->ops = &i915_gem_phys_ops;
> +
> + return i915_gem_object_get_pages(obj);
> }
>
> static int
> @@ -313,6 +386,13 @@ i915_gem_phys_pwrite(struct drm_i915_gem_object *obj,
> void *vaddr = obj->phys_handle->vaddr + args->offset;
> char __user *user_data = to_user_ptr(args->data_ptr);
>
> + /* We manually control the domain here and pretend that it
> + * remains coherent i.e. in the GTT domain, like shmem_pwrite.
> + */
> + ret = i915_gem_object_wait_rendering(obj, false);
> + if (ret)
> + return ret;
> +
> if (__copy_from_user_inatomic_nocache(vaddr, user_data, args->size)) {
> unsigned long unwritten;
>
> @@ -327,6 +407,7 @@ i915_gem_phys_pwrite(struct drm_i915_gem_object *obj,
> return -EFAULT;
> }
>
> + drm_clflush_virt_range(vaddr, args->size);
> i915_gem_chipset_flush(dev);
> return 0;
> }
> @@ -1190,11 +1271,6 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
> * pread/pwrite currently are reading and writing from the CPU
> * perspective, requiring manual detiling by the client.
> */
> - if (obj->phys_handle) {
> - ret = i915_gem_phys_pwrite(obj, args, file);
> - goto out;
> - }
> -
> if (obj->tiling_mode == I915_TILING_NONE &&
> (obj->base.filp == NULL ||
> (obj->base.write_domain != I915_GEM_DOMAIN_CPU &&
> @@ -1205,8 +1281,12 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
> * textures). Fallback to the shmem path in that case. */
> }
>
> - if (ret == -EFAULT || ret == -ENOSPC)
> - ret = i915_gem_shmem_pwrite(dev, obj, args, file);
> + if (ret == -EFAULT || ret == -ENOSPC) {
> + if (obj->phys_handle)
> + ret = i915_gem_phys_pwrite(obj, args, file);
> + else
> + ret = i915_gem_shmem_pwrite(dev, obj, args, file);
> + }
>
> out:
> drm_gem_object_unreference(&obj->base);
> @@ -3646,7 +3726,7 @@ i915_gem_clflush_object(struct drm_i915_gem_object *obj,
> * Stolen memory is always coherent with the GPU as it is explicitly
> * marked as wc by the system, or the system is cache-coherent.
> */
> - if (obj->stolen)
> + if (obj->stolen || obj->phys_handle)
> return false;
>
> /* If the GPU is snooping the contents of the CPU cache,
> @@ -4579,8 +4659,6 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj)
> }
> }
>
> - i915_gem_object_detach_phys(obj);
> -
> /* Stolen objects don't hold a ref, but do hold pin count. Fix that up
> * before progressing. */
> if (obj->stolen)
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index b6498a43497e..50d905483d8b 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -390,6 +390,7 @@ typedef struct drm_i915_irq_wait {
> #define I915_PARAM_HAS_EXEC_HANDLE_LUT 26
> #define I915_PARAM_HAS_WT 27
> #define I915_PARAM_CMD_PARSER_VERSION 28
> +#define I915_PARAM_HAS_COHERENT_PHYS_GTT 29
>
> typedef struct drm_i915_getparam {
> int param;
> --
> 2.0.0
>
> _______________________________________________
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> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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