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drm/vgem: use shmem helpers

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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_PFNMAP, 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 0cf2ef46c6 ("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

v7: I absolutely butchered the rebases over the vgem mmap change and
revert and broke the patch. Actually go back to v6 from before the
vgem mmap changes.

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>
Link: https://patchwork.freedesktop.org/patch/msgid/20210812131412.2487363-4-daniel.vetter@ffwll.ch
This commit is contained in:
Daniel Vetter 2021-08-12 15:14:12 +02:00
parent 804b6e5ee6
commit 45d9c8dde4
2 changed files with 17 additions and 332 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
drivers/gpu/drm/Kconfig
View file

@ -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

344
drivers/gpu/drm/vgem/vgem_drv.c
View file

@ -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)
DEFINE_DRM_GEM_FOPS(vgem_driver_fops);
static struct drm_gem_object *vgem_gem_create_object(struct drm_device *dev, size_t size)
{
unsigned long flags = vma->vm_flags;
int ret;
struct drm_gem_shmem_object *obj;
ret = drm_gem_mmap(filp, vma);
if (ret)
return ret;
obj = kzalloc(sizeof(*obj), GFP_KERNEL);
if (!obj)
return NULL;
/* Keep the WC mmaping set by drm_gem_mmap() but our pages
* are ordinary and not special.
/*
* vgem doesn't have any begin/end cpu access ioctls, therefore must use
* coherent memory or dma-buf sharing just wont work.
*/
vma->vm_flags = flags | VM_DONTEXPAND | VM_DONTDUMP;
return 0;
}
obj->map_wc = true;
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)
{
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);
/* Flush the object from the CPU cache so that importers can rely
* on coherent indirect access via the exported dma-address.
*/
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->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,