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* [PATCH 1/2] dma-buf: Require VM_PFNMAP vma for mmap
@ 2021-02-23 10:59 Daniel Vetter
  2021-02-23 10:59 ` [PATCH 2/2] drm/vgem: use shmem helpers Daniel Vetter
                   ` (2 more replies)
  0 siblings, 3 replies; 40+ messages in thread
From: Daniel Vetter @ 2021-02-23 10:59 UTC (permalink / raw)
  To: DRI Development
  Cc: Daniel Vetter, Intel Graphics Development, Matthew Wilcox,
	linaro-mm-sig, Jason Gunthorpe, Daniel Vetter,
	Suren Baghdasaryan, Christian König, linux-media

tldr; DMA buffers aren't normal memory, expecting that you can use
them like that (like calling get_user_pages works, or that they're
accounting like any other normal memory) cannot be guaranteed.

Since some userspace only runs on integrated devices, where all
buffers are actually all resident system memory, there's a huge
temptation to assume that a struct page is always present and useable
like for any more pagecache backed mmap. This has the potential to
result in a uapi nightmare.

To stop this gap require that DMA buffer mmaps are VM_PFNMAP, which
blocks get_user_pages and all the other struct page based
infrastructure for everyone. In spirit this is the uapi counterpart to
the kernel-internal CONFIG_DMABUF_DEBUG.

Motivated by a recent patch which wanted to swich the system dma-buf
heap to vm_insert_page instead of vm_insert_pfn.

v2:

Jason brought up that we also want to guarantee that all ptes have the
pte_special flag set, to catch fast get_user_pages (on architectures
that support this). Allowing VM_MIXEDMAP (like VM_SPECIAL does) would
still allow vm_insert_page, but limiting to VM_PFNMAP will catch that.

From auditing the various functions to insert pfn pte entires
(vm_insert_pfn_prot, remap_pfn_range and all it's callers like
dma_mmap_wc) it looks like VM_PFNMAP is already required anyway, so
this should be the correct flag to check for.

References: https://lore.kernel.org/lkml/CAKMK7uHi+mG0z0HUmNt13QCCvutuRVjpcR0NjRL12k-WbWzkRg@mail.gmail.com/
Acked-by: Christian König <christian.koenig@amd.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
---
 drivers/dma-buf/dma-buf.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index f264b70c383e..06cb1d2e9fdc 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -127,6 +127,7 @@ static struct file_system_type dma_buf_fs_type = {
 static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
 {
 	struct dma_buf *dmabuf;
+	int ret;
 
 	if (!is_dma_buf_file(file))
 		return -EINVAL;
@@ -142,7 +143,11 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
 	    dmabuf->size >> PAGE_SHIFT)
 		return -EINVAL;
 
-	return dmabuf->ops->mmap(dmabuf, vma);
+	ret = dmabuf->ops->mmap(dmabuf, vma);
+
+	WARN_ON(!(vma->vm_flags & VM_PFNMAP));
+
+	return ret;
 }
 
 static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
@@ -1244,6 +1249,8 @@ EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
 int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
 		 unsigned long pgoff)
 {
+	int ret;
+
 	if (WARN_ON(!dmabuf || !vma))
 		return -EINVAL;
 
@@ -1264,7 +1271,11 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
 	vma_set_file(vma, dmabuf->file);
 	vma->vm_pgoff = pgoff;
 
-	return dmabuf->ops->mmap(dmabuf, vma);
+	ret = dmabuf->ops->mmap(dmabuf, vma);
+
+	WARN_ON(!(vma->vm_flags & VM_PFNMAP));
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(dma_buf_mmap);
 
-- 
2.30.0

_______________________________________________
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dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

^ permalink raw reply related	[flat|nested] 40+ messages in thread
* [PATCH v3 4/4] drm/vgem: use shmem helpers
@ 2021-06-03 16:41 Daniel Vetter
  2021-06-03 21:09 ` [PATCH] " Daniel Vetter
  0 siblings, 1 reply; 40+ messages in thread
From: Daniel Vetter @ 2021-06-03 16:41 UTC (permalink / raw)
  To: Intel Graphics Development
  Cc: Daniel Vetter, DRI Development, Melissa Wen, Thomas Zimmermann,
	Daniel Vetter, Chris Wilson, Christian König

Aside from deleting lots of code the real motivation here is to switch
the mmap over to VM_PFNMAP, to be more consistent with what real gpu
drivers do. They're all VM_PFNMP, which means get_user_pages doesn't
work, and even if you try and there's a struct page behind that,
touching it and mucking around with its refcount can upset drivers
real bad.

v2: Review from Thomas:
- sort #include
- drop more dead code that I didn't spot somehow

v3: select DRM_GEM_SHMEM_HELPER to make it build (intel-gfx-ci)

v4: I got tricked by 0cf2ef46c6c0 ("drm/shmem-helper: Use cached
mappings by default"), and we need WC in vgem because vgem doesn't
have explicit begin/end cpu access ioctls.

Also add a comment why exactly vgem has to use wc.

v5: Don't set obj->base.funcs, it will default to drm_gem_shmem_funcs
(Thomas)

Cc: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Melissa Wen <melissa.srw@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/Kconfig         |   1 +
 drivers/gpu/drm/vgem/vgem_drv.c | 342 ++------------------------------
 2 files changed, 14 insertions(+), 329 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 9c21527b791f..fb38ef7b3206 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -268,6 +268,7 @@ source "drivers/gpu/drm/kmb/Kconfig"
 config DRM_VGEM
 	tristate "Virtual GEM provider"
 	depends on DRM
+	select DRM_GEM_SHMEM_HELPER
 	help
 	  Choose this option to get a virtual graphics memory manager,
 	  as used by Mesa's software renderer for enhanced performance.
diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
index bf38a7e319d1..a87eafa89e9f 100644
--- a/drivers/gpu/drm/vgem/vgem_drv.c
+++ b/drivers/gpu/drm/vgem/vgem_drv.c
@@ -38,6 +38,7 @@
 
 #include <drm/drm_drv.h>
 #include <drm/drm_file.h>
+#include <drm/drm_gem_shmem_helper.h>
 #include <drm/drm_ioctl.h>
 #include <drm/drm_managed.h>
 #include <drm/drm_prime.h>
@@ -50,87 +51,11 @@
 #define DRIVER_MAJOR	1
 #define DRIVER_MINOR	0
 
-static const struct drm_gem_object_funcs vgem_gem_object_funcs;
-
 static struct vgem_device {
 	struct drm_device drm;
 	struct platform_device *platform;
 } *vgem_device;
 
-static void vgem_gem_free_object(struct drm_gem_object *obj)
-{
-	struct drm_vgem_gem_object *vgem_obj = to_vgem_bo(obj);
-
-	kvfree(vgem_obj->pages);
-	mutex_destroy(&vgem_obj->pages_lock);
-
-	if (obj->import_attach)
-		drm_prime_gem_destroy(obj, vgem_obj->table);
-
-	drm_gem_object_release(obj);
-	kfree(vgem_obj);
-}
-
-static vm_fault_t vgem_gem_fault(struct vm_fault *vmf)
-{
-	struct vm_area_struct *vma = vmf->vma;
-	struct drm_vgem_gem_object *obj = vma->vm_private_data;
-	/* We don't use vmf->pgoff since that has the fake offset */
-	unsigned long vaddr = vmf->address;
-	vm_fault_t ret = VM_FAULT_SIGBUS;
-	loff_t num_pages;
-	pgoff_t page_offset;
-	page_offset = (vaddr - vma->vm_start) >> PAGE_SHIFT;
-
-	num_pages = DIV_ROUND_UP(obj->base.size, PAGE_SIZE);
-
-	if (page_offset >= num_pages)
-		return VM_FAULT_SIGBUS;
-
-	mutex_lock(&obj->pages_lock);
-	if (obj->pages) {
-		get_page(obj->pages[page_offset]);
-		vmf->page = obj->pages[page_offset];
-		ret = 0;
-	}
-	mutex_unlock(&obj->pages_lock);
-	if (ret) {
-		struct page *page;
-
-		page = shmem_read_mapping_page(
-					file_inode(obj->base.filp)->i_mapping,
-					page_offset);
-		if (!IS_ERR(page)) {
-			vmf->page = page;
-			ret = 0;
-		} else switch (PTR_ERR(page)) {
-			case -ENOSPC:
-			case -ENOMEM:
-				ret = VM_FAULT_OOM;
-				break;
-			case -EBUSY:
-				ret = VM_FAULT_RETRY;
-				break;
-			case -EFAULT:
-			case -EINVAL:
-				ret = VM_FAULT_SIGBUS;
-				break;
-			default:
-				WARN_ON(PTR_ERR(page));
-				ret = VM_FAULT_SIGBUS;
-				break;
-		}
-
-	}
-	return ret;
-}
-
-static const struct vm_operations_struct vgem_gem_vm_ops = {
-	.fault = vgem_gem_fault,
-	.open = drm_gem_vm_open,
-	.close = drm_gem_vm_close,
-};
-
 static int vgem_open(struct drm_device *dev, struct drm_file *file)
 {
 	struct vgem_file *vfile;
@@ -159,266 +84,30 @@ static void vgem_postclose(struct drm_device *dev, struct drm_file *file)
 	kfree(vfile);
 }
 
-static struct drm_vgem_gem_object *__vgem_gem_create(struct drm_device *dev,
-						unsigned long size)
-{
-	struct drm_vgem_gem_object *obj;
-	int ret;
-
-	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
-	if (!obj)
-		return ERR_PTR(-ENOMEM);
-
-	obj->base.funcs = &vgem_gem_object_funcs;
-
-	ret = drm_gem_object_init(dev, &obj->base, roundup(size, PAGE_SIZE));
-	if (ret) {
-		kfree(obj);
-		return ERR_PTR(ret);
-	}
-
-	mutex_init(&obj->pages_lock);
-
-	return obj;
-}
-
-static void __vgem_gem_destroy(struct drm_vgem_gem_object *obj)
-{
-	drm_gem_object_release(&obj->base);
-	kfree(obj);
-}
-
-static struct drm_gem_object *vgem_gem_create(struct drm_device *dev,
-					      struct drm_file *file,
-					      unsigned int *handle,
-					      unsigned long size)
-{
-	struct drm_vgem_gem_object *obj;
-	int ret;
-
-	obj = __vgem_gem_create(dev, size);
-	if (IS_ERR(obj))
-		return ERR_CAST(obj);
-
-	ret = drm_gem_handle_create(file, &obj->base, handle);
-	if (ret) {
-		drm_gem_object_put(&obj->base);
-		return ERR_PTR(ret);
-	}
-
-	return &obj->base;
-}
-
-static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
-				struct drm_mode_create_dumb *args)
-{
-	struct drm_gem_object *gem_object;
-	u64 pitch, size;
-
-	pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
-	size = args->height * pitch;
-	if (size == 0)
-		return -EINVAL;
-
-	gem_object = vgem_gem_create(dev, file, &args->handle, size);
-	if (IS_ERR(gem_object))
-		return PTR_ERR(gem_object);
-
-	args->size = gem_object->size;
-	args->pitch = pitch;
-
-	drm_gem_object_put(gem_object);
-
-	DRM_DEBUG("Created object of size %llu\n", args->size);
-
-	return 0;
-}
-
 static struct drm_ioctl_desc vgem_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(VGEM_FENCE_ATTACH, vgem_fence_attach_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(VGEM_FENCE_SIGNAL, vgem_fence_signal_ioctl, DRM_RENDER_ALLOW),
 };
 
-static int vgem_mmap(struct file *filp, struct vm_area_struct *vma)
-{
-	unsigned long flags = vma->vm_flags;
-	int ret;
-
-	ret = drm_gem_mmap(filp, vma);
-	if (ret)
-		return ret;
-
-	/* Keep the WC mmaping set by drm_gem_mmap() but our pages
-	 * are ordinary and not special.
-	 */
-	vma->vm_flags = flags | VM_DONTEXPAND | VM_DONTDUMP;
-	return 0;
-}
+DEFINE_DRM_GEM_FOPS(vgem_driver_fops);
 
-static const struct file_operations vgem_driver_fops = {
-	.owner		= THIS_MODULE,
-	.open		= drm_open,
-	.mmap		= vgem_mmap,
-	.poll		= drm_poll,
-	.read		= drm_read,
-	.unlocked_ioctl = drm_ioctl,
-	.compat_ioctl	= drm_compat_ioctl,
-	.release	= drm_release,
-};
-
-static struct page **vgem_pin_pages(struct drm_vgem_gem_object *bo)
-{
-	mutex_lock(&bo->pages_lock);
-	if (bo->pages_pin_count++ == 0) {
-		struct page **pages;
-
-		pages = drm_gem_get_pages(&bo->base);
-		if (IS_ERR(pages)) {
-			bo->pages_pin_count--;
-			mutex_unlock(&bo->pages_lock);
-			return pages;
-		}
-
-		bo->pages = pages;
-	}
-	mutex_unlock(&bo->pages_lock);
-
-	return bo->pages;
-}
-
-static void vgem_unpin_pages(struct drm_vgem_gem_object *bo)
-{
-	mutex_lock(&bo->pages_lock);
-	if (--bo->pages_pin_count == 0) {
-		drm_gem_put_pages(&bo->base, bo->pages, true, true);
-		bo->pages = NULL;
-	}
-	mutex_unlock(&bo->pages_lock);
-}
-
-static int vgem_prime_pin(struct drm_gem_object *obj)
+static struct drm_gem_object *vgem_gem_create_object(struct drm_device *dev, size_t size)
 {
-	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
-	long n_pages = obj->size >> PAGE_SHIFT;
-	struct page **pages;
+	struct drm_gem_shmem_object *obj;
 
-	pages = vgem_pin_pages(bo);
-	if (IS_ERR(pages))
-		return PTR_ERR(pages);
+	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
+	if (!obj)
+		return NULL;
 
-	/* Flush the object from the CPU cache so that importers can rely
-	 * on coherent indirect access via the exported dma-address.
+	/*
+	 * vgem doesn't have any begin/end cpu access ioctls, therefore must use
+	 * coherent memory or dma-buf sharing just wont work.
 	 */
-	drm_clflush_pages(pages, n_pages);
-
-	return 0;
-}
-
-static void vgem_prime_unpin(struct drm_gem_object *obj)
-{
-	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
-
-	vgem_unpin_pages(bo);
-}
-
-static struct sg_table *vgem_prime_get_sg_table(struct drm_gem_object *obj)
-{
-	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
-
-	return drm_prime_pages_to_sg(obj->dev, bo->pages, bo->base.size >> PAGE_SHIFT);
-}
-
-static struct drm_gem_object* vgem_prime_import(struct drm_device *dev,
-						struct dma_buf *dma_buf)
-{
-	struct vgem_device *vgem = container_of(dev, typeof(*vgem), drm);
-
-	return drm_gem_prime_import_dev(dev, dma_buf, &vgem->platform->dev);
-}
-
-static struct drm_gem_object *vgem_prime_import_sg_table(struct drm_device *dev,
-			struct dma_buf_attachment *attach, struct sg_table *sg)
-{
-	struct drm_vgem_gem_object *obj;
-	int npages;
-
-	obj = __vgem_gem_create(dev, attach->dmabuf->size);
-	if (IS_ERR(obj))
-		return ERR_CAST(obj);
+	obj->map_wc = true;
 
-	npages = PAGE_ALIGN(attach->dmabuf->size) / PAGE_SIZE;
-
-	obj->table = sg;
-	obj->pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
-	if (!obj->pages) {
-		__vgem_gem_destroy(obj);
-		return ERR_PTR(-ENOMEM);
-	}
-
-	obj->pages_pin_count++; /* perma-pinned */
-	drm_prime_sg_to_page_array(obj->table, obj->pages, npages);
 	return &obj->base;
 }
 
-static int vgem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
-{
-	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
-	long n_pages = obj->size >> PAGE_SHIFT;
-	struct page **pages;
-	void *vaddr;
-
-	pages = vgem_pin_pages(bo);
-	if (IS_ERR(pages))
-		return PTR_ERR(pages);
-
-	vaddr = vmap(pages, n_pages, 0, pgprot_writecombine(PAGE_KERNEL));
-	if (!vaddr)
-		return -ENOMEM;
-	dma_buf_map_set_vaddr(map, vaddr);
-
-	return 0;
-}
-
-static void vgem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map)
-{
-	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
-
-	vunmap(map->vaddr);
-	vgem_unpin_pages(bo);
-}
-
-static int vgem_prime_mmap(struct drm_gem_object *obj,
-			   struct vm_area_struct *vma)
-{
-	int ret;
-
-	if (obj->size < vma->vm_end - vma->vm_start)
-		return -EINVAL;
-
-	if (!obj->filp)
-		return -ENODEV;
-
-	ret = call_mmap(obj->filp, vma);
-	if (ret)
-		return ret;
-
-	vma_set_file(vma, obj->filp);
-	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
-	vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
-
-	return 0;
-}
-
-static const struct drm_gem_object_funcs vgem_gem_object_funcs = {
-	.free = vgem_gem_free_object,
-	.pin = vgem_prime_pin,
-	.unpin = vgem_prime_unpin,
-	.get_sg_table = vgem_prime_get_sg_table,
-	.vmap = vgem_prime_vmap,
-	.vunmap = vgem_prime_vunmap,
-	.vm_ops = &vgem_gem_vm_ops,
-};
-
 static const struct drm_driver vgem_driver = {
 	.driver_features		= DRIVER_GEM | DRIVER_RENDER,
 	.open				= vgem_open,
@@ -427,13 +116,8 @@ static const struct drm_driver vgem_driver = {
 	.num_ioctls 			= ARRAY_SIZE(vgem_ioctls),
 	.fops				= &vgem_driver_fops,
 
-	.dumb_create			= vgem_gem_dumb_create,
-
-	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
-	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
-	.gem_prime_import = vgem_prime_import,
-	.gem_prime_import_sg_table = vgem_prime_import_sg_table,
-	.gem_prime_mmap = vgem_prime_mmap,
+	DRM_GEM_SHMEM_DRIVER_OPS,
+	.gem_create_object		= vgem_gem_create_object,
 
 	.name	= DRIVER_NAME,
 	.desc	= DRIVER_DESC,
-- 
2.31.0


^ permalink raw reply related	[flat|nested] 40+ messages in thread
* [PATCH v4 4/4] drm/vgem: use shmem helpers
@ 2021-07-13 20:51 Daniel Vetter
  2021-07-14 12:45 ` [PATCH] " Daniel Vetter
  0 siblings, 1 reply; 40+ messages in thread
From: Daniel Vetter @ 2021-07-13 20:51 UTC (permalink / raw)
  To: Intel Graphics Development
  Cc: Daniel Vetter, DRI Development, Melissa Wen, Thomas Zimmermann,
	Daniel Vetter, Chris Wilson, Christian König

Aside from deleting lots of code the real motivation here is to switch
the mmap over to VM_PFNMAP, to be more consistent with what real gpu
drivers do. They're all VM_PFNMP, which means get_user_pages doesn't
work, and even if you try and there's a struct page behind that,
touching it and mucking around with its refcount can upset drivers
real bad.

v2: Review from Thomas:
- sort #include
- drop more dead code that I didn't spot somehow

v3: select DRM_GEM_SHMEM_HELPER to make it build (intel-gfx-ci)

v4: I got tricked by 0cf2ef46c6c0 ("drm/shmem-helper: Use cached
mappings by default"), and we need WC in vgem because vgem doesn't
have explicit begin/end cpu access ioctls.

Also add a comment why exactly vgem has to use wc.

v5: Don't set obj->base.funcs, it will default to drm_gem_shmem_funcs
(Thomas)

v6: vgem also needs an MMU for remapping

Cc: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Melissa Wen <melissa.srw@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/Kconfig         |   5 +-
 drivers/gpu/drm/vgem/vgem_drv.c | 315 ++------------------------------
 2 files changed, 15 insertions(+), 305 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 314eefa39892..28f7d2006e8b 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -272,7 +272,8 @@ source "drivers/gpu/drm/kmb/Kconfig"
 
 config DRM_VGEM
 	tristate "Virtual GEM provider"
-	depends on DRM
+	depends on DRM && MMU
+	select DRM_GEM_SHMEM_HELPER
 	help
 	  Choose this option to get a virtual graphics memory manager,
 	  as used by Mesa's software renderer for enhanced performance.
@@ -280,7 +281,7 @@ config DRM_VGEM
 
 config DRM_VKMS
 	tristate "Virtual KMS (EXPERIMENTAL)"
-	depends on DRM
+	depends on DRM && MMU
 	select DRM_KMS_HELPER
 	select DRM_GEM_SHMEM_HELPER
 	select CRC32
diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
index bf38a7e319d1..ba410ba6b7f7 100644
--- a/drivers/gpu/drm/vgem/vgem_drv.c
+++ b/drivers/gpu/drm/vgem/vgem_drv.c
@@ -38,6 +38,7 @@
 
 #include <drm/drm_drv.h>
 #include <drm/drm_file.h>
+#include <drm/drm_gem_shmem_helper.h>
 #include <drm/drm_ioctl.h>
 #include <drm/drm_managed.h>
 #include <drm/drm_prime.h>
@@ -50,87 +51,11 @@
 #define DRIVER_MAJOR	1
 #define DRIVER_MINOR	0
 
-static const struct drm_gem_object_funcs vgem_gem_object_funcs;
-
 static struct vgem_device {
 	struct drm_device drm;
 	struct platform_device *platform;
 } *vgem_device;
 
-static void vgem_gem_free_object(struct drm_gem_object *obj)
-{
-	struct drm_vgem_gem_object *vgem_obj = to_vgem_bo(obj);
-
-	kvfree(vgem_obj->pages);
-	mutex_destroy(&vgem_obj->pages_lock);
-
-	if (obj->import_attach)
-		drm_prime_gem_destroy(obj, vgem_obj->table);
-
-	drm_gem_object_release(obj);
-	kfree(vgem_obj);
-}
-
-static vm_fault_t vgem_gem_fault(struct vm_fault *vmf)
-{
-	struct vm_area_struct *vma = vmf->vma;
-	struct drm_vgem_gem_object *obj = vma->vm_private_data;
-	/* We don't use vmf->pgoff since that has the fake offset */
-	unsigned long vaddr = vmf->address;
-	vm_fault_t ret = VM_FAULT_SIGBUS;
-	loff_t num_pages;
-	pgoff_t page_offset;
-	page_offset = (vaddr - vma->vm_start) >> PAGE_SHIFT;
-
-	num_pages = DIV_ROUND_UP(obj->base.size, PAGE_SIZE);
-
-	if (page_offset >= num_pages)
-		return VM_FAULT_SIGBUS;
-
-	mutex_lock(&obj->pages_lock);
-	if (obj->pages) {
-		get_page(obj->pages[page_offset]);
-		vmf->page = obj->pages[page_offset];
-		ret = 0;
-	}
-	mutex_unlock(&obj->pages_lock);
-	if (ret) {
-		struct page *page;
-
-		page = shmem_read_mapping_page(
-					file_inode(obj->base.filp)->i_mapping,
-					page_offset);
-		if (!IS_ERR(page)) {
-			vmf->page = page;
-			ret = 0;
-		} else switch (PTR_ERR(page)) {
-			case -ENOSPC:
-			case -ENOMEM:
-				ret = VM_FAULT_OOM;
-				break;
-			case -EBUSY:
-				ret = VM_FAULT_RETRY;
-				break;
-			case -EFAULT:
-			case -EINVAL:
-				ret = VM_FAULT_SIGBUS;
-				break;
-			default:
-				WARN_ON(PTR_ERR(page));
-				ret = VM_FAULT_SIGBUS;
-				break;
-		}
-
-	}
-	return ret;
-}
-
-static const struct vm_operations_struct vgem_gem_vm_ops = {
-	.fault = vgem_gem_fault,
-	.open = drm_gem_vm_open,
-	.close = drm_gem_vm_close,
-};
-
 static int vgem_open(struct drm_device *dev, struct drm_file *file)
 {
 	struct vgem_file *vfile;
@@ -159,81 +84,6 @@ static void vgem_postclose(struct drm_device *dev, struct drm_file *file)
 	kfree(vfile);
 }
 
-static struct drm_vgem_gem_object *__vgem_gem_create(struct drm_device *dev,
-						unsigned long size)
-{
-	struct drm_vgem_gem_object *obj;
-	int ret;
-
-	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
-	if (!obj)
-		return ERR_PTR(-ENOMEM);
-
-	obj->base.funcs = &vgem_gem_object_funcs;
-
-	ret = drm_gem_object_init(dev, &obj->base, roundup(size, PAGE_SIZE));
-	if (ret) {
-		kfree(obj);
-		return ERR_PTR(ret);
-	}
-
-	mutex_init(&obj->pages_lock);
-
-	return obj;
-}
-
-static void __vgem_gem_destroy(struct drm_vgem_gem_object *obj)
-{
-	drm_gem_object_release(&obj->base);
-	kfree(obj);
-}
-
-static struct drm_gem_object *vgem_gem_create(struct drm_device *dev,
-					      struct drm_file *file,
-					      unsigned int *handle,
-					      unsigned long size)
-{
-	struct drm_vgem_gem_object *obj;
-	int ret;
-
-	obj = __vgem_gem_create(dev, size);
-	if (IS_ERR(obj))
-		return ERR_CAST(obj);
-
-	ret = drm_gem_handle_create(file, &obj->base, handle);
-	if (ret) {
-		drm_gem_object_put(&obj->base);
-		return ERR_PTR(ret);
-	}
-
-	return &obj->base;
-}
-
-static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
-				struct drm_mode_create_dumb *args)
-{
-	struct drm_gem_object *gem_object;
-	u64 pitch, size;
-
-	pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
-	size = args->height * pitch;
-	if (size == 0)
-		return -EINVAL;
-
-	gem_object = vgem_gem_create(dev, file, &args->handle, size);
-	if (IS_ERR(gem_object))
-		return PTR_ERR(gem_object);
-
-	args->size = gem_object->size;
-	args->pitch = pitch;
-
-	drm_gem_object_put(gem_object);
-
-	DRM_DEBUG("Created object of size %llu\n", args->size);
-
-	return 0;
-}
-
 static struct drm_ioctl_desc vgem_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(VGEM_FENCE_ATTACH, vgem_fence_attach_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(VGEM_FENCE_SIGNAL, vgem_fence_signal_ioctl, DRM_RENDER_ALLOW),
@@ -266,159 +116,23 @@ static const struct file_operations vgem_driver_fops = {
 	.release	= drm_release,
 };
 
-static struct page **vgem_pin_pages(struct drm_vgem_gem_object *bo)
-{
-	mutex_lock(&bo->pages_lock);
-	if (bo->pages_pin_count++ == 0) {
-		struct page **pages;
-
-		pages = drm_gem_get_pages(&bo->base);
-		if (IS_ERR(pages)) {
-			bo->pages_pin_count--;
-			mutex_unlock(&bo->pages_lock);
-			return pages;
-		}
-
-		bo->pages = pages;
-	}
-	mutex_unlock(&bo->pages_lock);
-
-	return bo->pages;
-}
-
-static void vgem_unpin_pages(struct drm_vgem_gem_object *bo)
+static struct drm_gem_object *vgem_gem_create_object(struct drm_device *dev, size_t size)
 {
-	mutex_lock(&bo->pages_lock);
-	if (--bo->pages_pin_count == 0) {
-		drm_gem_put_pages(&bo->base, bo->pages, true, true);
-		bo->pages = NULL;
-	}
-	mutex_unlock(&bo->pages_lock);
-}
+	struct drm_gem_shmem_object *obj;
 
-static int vgem_prime_pin(struct drm_gem_object *obj)
-{
-	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
-	long n_pages = obj->size >> PAGE_SHIFT;
-	struct page **pages;
-
-	pages = vgem_pin_pages(bo);
-	if (IS_ERR(pages))
-		return PTR_ERR(pages);
+	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
+	if (!obj)
+		return NULL;
 
-	/* Flush the object from the CPU cache so that importers can rely
-	 * on coherent indirect access via the exported dma-address.
+	/*
+	 * vgem doesn't have any begin/end cpu access ioctls, therefore must use
+	 * coherent memory or dma-buf sharing just wont work.
 	 */
-	drm_clflush_pages(pages, n_pages);
-
-	return 0;
-}
-
-static void vgem_prime_unpin(struct drm_gem_object *obj)
-{
-	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
-
-	vgem_unpin_pages(bo);
-}
-
-static struct sg_table *vgem_prime_get_sg_table(struct drm_gem_object *obj)
-{
-	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
-
-	return drm_prime_pages_to_sg(obj->dev, bo->pages, bo->base.size >> PAGE_SHIFT);
-}
-
-static struct drm_gem_object* vgem_prime_import(struct drm_device *dev,
-						struct dma_buf *dma_buf)
-{
-	struct vgem_device *vgem = container_of(dev, typeof(*vgem), drm);
-
-	return drm_gem_prime_import_dev(dev, dma_buf, &vgem->platform->dev);
-}
-
-static struct drm_gem_object *vgem_prime_import_sg_table(struct drm_device *dev,
-			struct dma_buf_attachment *attach, struct sg_table *sg)
-{
-	struct drm_vgem_gem_object *obj;
-	int npages;
-
-	obj = __vgem_gem_create(dev, attach->dmabuf->size);
-	if (IS_ERR(obj))
-		return ERR_CAST(obj);
-
-	npages = PAGE_ALIGN(attach->dmabuf->size) / PAGE_SIZE;
-
-	obj->table = sg;
-	obj->pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
-	if (!obj->pages) {
-		__vgem_gem_destroy(obj);
-		return ERR_PTR(-ENOMEM);
-	}
+	obj->map_wc = true;
 
-	obj->pages_pin_count++; /* perma-pinned */
-	drm_prime_sg_to_page_array(obj->table, obj->pages, npages);
 	return &obj->base;
 }
 
-static int vgem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
-{
-	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
-	long n_pages = obj->size >> PAGE_SHIFT;
-	struct page **pages;
-	void *vaddr;
-
-	pages = vgem_pin_pages(bo);
-	if (IS_ERR(pages))
-		return PTR_ERR(pages);
-
-	vaddr = vmap(pages, n_pages, 0, pgprot_writecombine(PAGE_KERNEL));
-	if (!vaddr)
-		return -ENOMEM;
-	dma_buf_map_set_vaddr(map, vaddr);
-
-	return 0;
-}
-
-static void vgem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map)
-{
-	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
-
-	vunmap(map->vaddr);
-	vgem_unpin_pages(bo);
-}
-
-static int vgem_prime_mmap(struct drm_gem_object *obj,
-			   struct vm_area_struct *vma)
-{
-	int ret;
-
-	if (obj->size < vma->vm_end - vma->vm_start)
-		return -EINVAL;
-
-	if (!obj->filp)
-		return -ENODEV;
-
-	ret = call_mmap(obj->filp, vma);
-	if (ret)
-		return ret;
-
-	vma_set_file(vma, obj->filp);
-	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
-	vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
-
-	return 0;
-}
-
-static const struct drm_gem_object_funcs vgem_gem_object_funcs = {
-	.free = vgem_gem_free_object,
-	.pin = vgem_prime_pin,
-	.unpin = vgem_prime_unpin,
-	.get_sg_table = vgem_prime_get_sg_table,
-	.vmap = vgem_prime_vmap,
-	.vunmap = vgem_prime_vunmap,
-	.vm_ops = &vgem_gem_vm_ops,
-};
-
 static const struct drm_driver vgem_driver = {
 	.driver_features		= DRIVER_GEM | DRIVER_RENDER,
 	.open				= vgem_open,
@@ -427,13 +141,8 @@ static const struct drm_driver vgem_driver = {
 	.num_ioctls 			= ARRAY_SIZE(vgem_ioctls),
 	.fops				= &vgem_driver_fops,
 
-	.dumb_create			= vgem_gem_dumb_create,
-
-	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
-	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
-	.gem_prime_import = vgem_prime_import,
-	.gem_prime_import_sg_table = vgem_prime_import_sg_table,
-	.gem_prime_mmap = vgem_prime_mmap,
+	DRM_GEM_SHMEM_DRIVER_OPS,
+	.gem_create_object		= vgem_gem_create_object,
 
 	.name	= DRIVER_NAME,
 	.desc	= DRIVER_DESC,
-- 
2.32.0


^ permalink raw reply related	[flat|nested] 40+ messages in thread
end of thread, other threads:[~2021-07-14 12:45 UTC | newest]

Thread overview: 40+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-23 10:59 [PATCH 1/2] dma-buf: Require VM_PFNMAP vma for mmap Daniel Vetter
2021-02-23 10:59 ` [PATCH 2/2] drm/vgem: use shmem helpers Daniel Vetter
2021-02-23 11:19   ` Thomas Zimmermann
2021-02-23 11:51   ` [PATCH] " Daniel Vetter
2021-02-23 14:21   ` [PATCH 2/2] " kernel test robot
2021-02-23 15:07   ` kernel test robot
2021-02-25 10:23   ` [PATCH] " Daniel Vetter
2021-02-26  9:19     ` Thomas Zimmermann
2021-02-26 13:30       ` Daniel Vetter
2021-02-26 13:51         ` Thomas Zimmermann
2021-02-26 14:04           ` Daniel Vetter
2021-02-24  7:46 ` [Linaro-mm-sig] [PATCH 1/2] dma-buf: Require VM_PFNMAP vma for mmap Thomas Hellström (Intel)
2021-02-24  8:45   ` Daniel Vetter
2021-02-24  9:15     ` Thomas Hellström (Intel)
2021-02-24  9:31       ` Daniel Vetter
2021-02-25 10:28         ` Christian König
2021-02-25 10:44           ` Daniel Vetter
2021-02-25 15:49             ` Daniel Vetter
2021-02-25 16:53               ` Christian König
2021-02-26  9:41               ` Thomas Hellström (Intel)
2021-02-26 13:28                 ` Daniel Vetter
2021-02-27  8:06                   ` Thomas Hellström (Intel)
2021-03-01  8:28                     ` Daniel Vetter
2021-03-01  8:39                       ` Thomas Hellström (Intel)
2021-03-01  9:05                         ` Daniel Vetter
2021-03-01  9:21                           ` Thomas Hellström (Intel)
2021-03-01 10:17                             ` Christian König
2021-03-01 14:09                               ` Daniel Vetter
2021-03-11 10:22                                 ` Thomas Hellström (Intel)
2021-03-11 13:00                                   ` Daniel Vetter
2021-03-11 13:12                                     ` Thomas Hellström (Intel)
2021-03-11 13:17                                       ` Daniel Vetter
2021-03-11 15:37                                         ` Thomas Hellström (Intel)
2021-03-12  7:51                                         ` Christian König
2021-02-24 18:46     ` Jason Gunthorpe
2021-02-25 10:30       ` Christian König
2021-02-25 10:45         ` Daniel Vetter
2021-02-26  3:57 ` John Stultz
2021-06-03 16:41 [PATCH v3 4/4] drm/vgem: use shmem helpers Daniel Vetter
2021-06-03 21:09 ` [PATCH] " Daniel Vetter
2021-07-13 20:51 [PATCH v4 4/4] " Daniel Vetter
2021-07-14 12:45 ` [PATCH] " Daniel Vetter

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