[PATCH v6 5/6] drm/i915/gvt: Dmabuf support for GVT-g
Chris Wilson
chris at chris-wilson.co.uk
Thu Jun 1 09:15:47 UTC 2017
On Sat, May 27, 2017 at 04:38:51PM +0800, Xiaoguang Chen wrote:
> dmabuf for GVT-g can be exported to users who can use the dmabuf to show
> the desktop of vm which use intel vgpu.
>
> Currently we provide query and create new dmabuf operations.
>
> Users of dmabuf can cache some created dmabufs and related information
> such as the framebuffer's address, size, tiling mode, width, height etc.
> When refresh the screen first query the currnet vgpu's frambuffer and
> compare with the cached ones(address, size, tiling, width, height etc)
> if found one then reuse the found dmabuf to gain performance improvment.
>
> If there is no dmabuf created yet or not found in the cached dmabufs then
> need to create a new dmabuf. To create a dmabuf first a gem object will
> be created and the backing storage of this gem object is the vgpu's
> framebuffer(primary/cursor).
> Set caching mode, change tiling mode and set domains of this gem object
> is not supported.
> Then associate this gem object to a dmabuf and export this dmabuf.
> A file descriptor will be generated for this dmabuf and this file
> descriptor can be sent to user space to do display.
>
> Signed-off-by: Xiaoguang Chen <xiaoguang.chen at intel.com>
> ---
> drivers/gpu/drm/i915/gvt/Makefile | 2 +-
> drivers/gpu/drm/i915/gvt/dmabuf.c | 269 +++++++++++++++++++++++++++++++++
> drivers/gpu/drm/i915/gvt/dmabuf.h | 37 +++++
> drivers/gpu/drm/i915/gvt/gvt.h | 1 +
> drivers/gpu/drm/i915/i915_gem.c | 26 +++-
> drivers/gpu/drm/i915/i915_gem_object.h | 9 ++
> 6 files changed, 342 insertions(+), 2 deletions(-)
> create mode 100644 drivers/gpu/drm/i915/gvt/dmabuf.c
> create mode 100644 drivers/gpu/drm/i915/gvt/dmabuf.h
>
> diff --git a/drivers/gpu/drm/i915/gvt/Makefile b/drivers/gpu/drm/i915/gvt/Makefile
> index 192ca26..e480f7d 100644
> --- a/drivers/gpu/drm/i915/gvt/Makefile
> +++ b/drivers/gpu/drm/i915/gvt/Makefile
> @@ -2,7 +2,7 @@ GVT_DIR := gvt
> GVT_SOURCE := gvt.o aperture_gm.o handlers.o vgpu.o trace_points.o firmware.o \
> interrupt.o gtt.o cfg_space.o opregion.o mmio.o display.o edid.o \
> execlist.o scheduler.o sched_policy.o render.o cmd_parser.o \
> - fb_decoder.o
> + fb_decoder.o dmabuf.o
>
> ccflags-y += -I$(src) -I$(src)/$(GVT_DIR) -Wall
> i915-y += $(addprefix $(GVT_DIR)/, $(GVT_SOURCE))
> diff --git a/drivers/gpu/drm/i915/gvt/dmabuf.c b/drivers/gpu/drm/i915/gvt/dmabuf.c
> new file mode 100644
> index 0000000..c831e91
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gvt/dmabuf.c
> @@ -0,0 +1,269 @@
> +/*
> + * Copyright 2017 Intel Corporation. All rights reserved.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> + * DEALINGS IN THE SOFTWARE.
> + *
> + * Authors:
> + * Zhiyuan Lv <zhiyuan.lv at intel.com>
> + *
> + * Contributors:
> + * Xiaoguang Chen <xiaoguang.chen at intel.com>
> + */
> +
> +#include <linux/dma-buf.h>
> +#include <drm/drmP.h>
> +#include <linux/vfio.h>
> +
> +#include "i915_drv.h"
> +#include "gvt.h"
> +
> +#define GEN8_DECODE_PTE(pte) (pte & GENMASK_ULL(63, 12))
> +
> +static struct sg_table *intel_vgpu_gem_get_pages(
> + struct drm_i915_gem_object *obj)
> +{
> + struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
> + struct sg_table *st;
> + struct scatterlist *sg;
> + int i, ret;
> + gen8_pte_t __iomem *gtt_entries;
> + struct intel_vgpu_fb_info *fb_info;
> +
> + fb_info = (struct intel_vgpu_fb_info *)obj->gvt_info;
> + if (WARN_ON(!fb_info))
> + return ERR_PTR(-ENODEV);
> +
> + st = kmalloc(sizeof(*st), GFP_KERNEL);
> + if (!st) {
> + ret = -ENOMEM;
> + return ERR_PTR(ret);
Tidier.
> + }
> +
> + ret = sg_alloc_table(st, fb_info->fb_size, GFP_KERNEL);
> + if (ret) {
> + kfree(st);
> + return ERR_PTR(ret);
> + }
> + gtt_entries = (gen8_pte_t __iomem *)dev_priv->ggtt.gsm +
> + (fb_info->fb_addr >> PAGE_SHIFT);
> + for_each_sg(st->sgl, sg, fb_info->fb_size, i) {
> + sg->offset = 0;
> + sg->length = PAGE_SIZE;
> + sg_dma_address(sg) =
> + GEN8_DECODE_PTE(readq(>t_entries[i]));
> + sg_dma_len(sg) = PAGE_SIZE;
> + }
> +
> + return st;
> +}
> +
> +static void intel_vgpu_gem_put_pages(struct drm_i915_gem_object *obj,
> + struct sg_table *pages)
> +{
> + sg_free_table(pages);
> + kfree(pages);
> +}
> +
> +static const struct drm_i915_gem_object_ops intel_vgpu_gem_ops = {
> + .flags = I915_GEM_OBJECT_IS_PROXY,
> + .get_pages = intel_vgpu_gem_get_pages,
> + .put_pages = intel_vgpu_gem_put_pages,
> +};
> +
> +static struct drm_i915_gem_object *intel_vgpu_create_gem(struct drm_device *dev,
> + struct vfio_vgpu_plane_info *info)
> +{
> + struct drm_i915_private *dev_priv = to_i915(dev);
> + struct drm_i915_gem_object *obj;
> +
> + obj = i915_gem_object_alloc(dev_priv);
> + if (obj == NULL)
> + return NULL;
> +
> + drm_gem_private_object_init(dev, &obj->base,
> + info->size << PAGE_SHIFT);
> + i915_gem_object_init(obj, &intel_vgpu_gem_ops);
> +
> + obj->base.read_domains = I915_GEM_DOMAIN_GTT;
> + obj->base.write_domain = 0;
> + /* Change tiling mode from user space is not supported to a GVT-g's
> + * dma-buf gem object.
> + * We increase the obj's framebuffer_references to disable this kind
> + * of operation.
> + */
> + obj->framebuffer_references++;
If it is only for that, don't. Just use the is_proxy: return -EPERM. So
that you don't make the mistake of leaving the counter dangling and the
error code is consistent.
What you probably should consider though is setting obj->pin_display.
That will fix up coherency along a few more paths.
> + if (IS_SKYLAKE(dev_priv)) {
> + unsigned int tiling_mode = 0;
> + unsigned int stride = 0;
> +
> + switch (info->drm_format_mod << 10) {
> + case PLANE_CTL_TILED_LINEAR:
> + tiling_mode = I915_TILING_NONE;
> + break;
> + case PLANE_CTL_TILED_X:
> + tiling_mode = I915_TILING_X;
> + stride = info->stride;
> + break;
> + case PLANE_CTL_TILED_Y:
> + tiling_mode = I915_TILING_Y;
> + stride = info->stride;
> + break;
> + default:
> + gvt_dbg_core("not supported tiling mode\n");
> + }
> + obj->tiling_and_stride = tiling_mode | stride;
> + } else {
> + obj->tiling_and_stride = info->drm_format_mod ?
> + I915_TILING_X : 0;
> + }
> +
> + return obj;
> +}
> +
> +int intel_vgpu_query_plane(struct intel_vgpu *vgpu, void *args)
> +{
> + struct drm_device *dev = &vgpu->gvt->dev_priv->drm;
> + struct vfio_vgpu_plane_info *info = args;
> +
> + return intel_vgpu_get_plane_info(dev, vgpu, info);
> +}
> +
> +int intel_vgpu_create_dmabuf(struct intel_vgpu *vgpu, void *args)
> +{
> + struct dma_buf *dmabuf;
> + struct drm_i915_gem_object *obj;
> + struct drm_device *dev = &vgpu->gvt->dev_priv->drm;
> + struct vfio_vgpu_dmabuf_info *gvt_dmabuf = args;
> + struct intel_vgpu_fb_info *fb_info;
> + int ret;
> +
> + ret = intel_vgpu_get_plane_info(dev, vgpu, &gvt_dmabuf->plane_info);
> + if (ret != 0)
> + return ret;
> +
> + obj = intel_vgpu_create_gem(dev, &gvt_dmabuf->plane_info);
> + if (obj == NULL) {
> + gvt_vgpu_err("create gvt gem obj failed:%d\n", vgpu->id);
> + return -ENOMEM;
> + }
> + fb_info = kmalloc(sizeof(*fb_info), GFP_KERNEL);
> + if (!fb_info) {
> + i915_gem_object_put(obj);
> + gvt_vgpu_err("allocate intel vgpu fb info failed\n");
> + return -ENOMEM;
> + }
> + fb_info->fb_addr = gvt_dmabuf->plane_info.start;
> + fb_info->fb_size = gvt_dmabuf->plane_info.size;
> + fb_info->vgpu = vgpu;
> + obj->gvt_info = fb_info;
> +
> + dmabuf = i915_gem_prime_export(dev, &obj->base, DRM_CLOEXEC | DRM_RDWR);
> +
> + if (IS_ERR(dmabuf)) {
> + kfree(fb_info);
> + i915_gem_object_free(obj);
> + gvt_vgpu_err("export dma-buf failed\n");
Develop a habit for using onion unwind for errors.
> + return PTR_ERR(dmabuf);
> + }
> +
> + ret = dma_buf_fd(dmabuf, DRM_CLOEXEC | DRM_RDWR);
> + if (ret < 0) {
> + kfree(fb_info);
> + i915_gem_object_free(obj);
> + gvt_vgpu_err("create dma-buf fd failed ret:%d\n", ret);
> + return ret;
> + }
> + gvt_dmabuf->fd = ret;
> +
> + return 0;
> +}
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 0c1cbe9..14be3b0 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1609,6 +1609,12 @@ i915_gem_set_domain_ioctl(struct drm_device *dev, void *data,
> if (!obj)
> return -ENOENT;
>
> + /* proxy gem object does not support setting domain */
> + if (i915_gem_object_is_proxy(obj)) {
> + i915_gem_object_put(obj);
> + return -EPERM;
Hook into the onion.
> + }
> +
> /* Try to flush the object off the GPU without holding the lock.
> * We will repeat the flush holding the lock in the normal manner
> * to catch cases where we are gazumped.
> @@ -1677,6 +1683,12 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
> if (!obj)
> return -ENOENT;
>
> + /* proxy gem obj does not support this operation */
> + if (i915_gem_object_is_proxy(obj)) {
> + i915_gem_object_put(obj);
> + return -EPERM;
> + }
> +
> /* Pinned buffers may be scanout, so flush the cache */
> i915_gem_object_flush_if_display(obj);
> i915_gem_object_put(obj);
> @@ -1727,7 +1739,7 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
> */
> if (!obj->base.filp) {
> i915_gem_object_put(obj);
> - return -EINVAL;
> + return -EPERM;
> }
>
> addr = vm_mmap(obj->base.filp, 0, args->size,
> @@ -3717,6 +3729,12 @@ int i915_gem_set_caching_ioctl(struct drm_device *dev, void *data,
> if (!obj)
> return -ENOENT;
>
> + /* proxy gem obj does not support setting caching mode */
> + if (i915_gem_object_is_proxy(obj)) {
> + i915_gem_object_put(obj);
> + return -EPERM;
Use the onion.
> + }
> +
> if (obj->cache_level == level)
> goto out;
>
> @@ -4168,6 +4186,12 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
> if (!obj)
> return -ENOENT;
>
> + /* proxy gem obj does not support changing backding storage */
> + if (i915_gem_object_is_proxy(obj)) {
> + i915_gem_object_put(obj);
More onion.
> + return -EPERM;
> + }
> +
> err = mutex_lock_interruptible(&obj->mm.lock);
> if (err)
> goto out;
--
Chris Wilson, Intel Open Source Technology Centre
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