// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
* Xen para-virtual DRM device
*
* Copyright (C) 2016-2018 EPAM Systems Inc.
*
* Author: Oleksandr Andrushchenko <[email protected]>
*/
#include <linux/dma-buf.h>
#include <linux/scatterlist.h>
#include <linux/shmem_fs.h>
#include <linux/vmalloc.h>
#include <drm/drm_gem.h>
#include <drm/drm_prime.h>
#include <drm/drm_probe_helper.h>
#include <xen/balloon.h>
#include <xen/xen.h>
#include "xen_drm_front.h"
#include "xen_drm_front_gem.h"
struct xen_gem_object {
struct drm_gem_object base;
size_t num_pages;
struct page **pages;
/* set for buffers allocated by the backend */
bool be_alloc;
/* this is for imported PRIME buffer */
struct sg_table *sgt_imported;
};
static inline struct xen_gem_object *
to_xen_gem_obj(struct drm_gem_object *gem_obj)
{
return container_of(gem_obj, struct xen_gem_object, base);
}
static int gem_alloc_pages_array(struct xen_gem_object *xen_obj,
size_t buf_size)
{
xen_obj->num_pages = DIV_ROUND_UP(buf_size, PAGE_SIZE);
xen_obj->pages = kvmalloc_array(xen_obj->num_pages,
sizeof(struct page *), GFP_KERNEL);
return !xen_obj->pages ? -ENOMEM : 0;
}
static void gem_free_pages_array(struct xen_gem_object *xen_obj)
{
kvfree(xen_obj->pages);
xen_obj->pages = NULL;
}
static int xen_drm_front_gem_object_mmap(struct drm_gem_object *gem_obj,
struct vm_area_struct *vma)
{
struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
int ret;
vma->vm_ops = gem_obj->funcs->vm_ops;
/*
* Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
* vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
* the whole buffer.
*/
vm_flags_mod(vma, VM_MIXEDMAP | VM_DONTEXPAND, VM_PFNMAP);
vma->vm_pgoff = 0;
/*
* According to Xen on ARM ABI (xen/include/public/arch-arm.h):
* all memory which is shared with other entities in the system
* (including the hypervisor and other guests) must reside in memory
* which is mapped as Normal Inner Write-Back Outer Write-Back
* Inner-Shareable.
*/
vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
/*
* vm_operations_struct.fault handler will be called if CPU access
* to VM is here. For GPUs this isn't the case, because CPU doesn't
* touch the memory. Insert pages now, so both CPU and GPU are happy.
*
* FIXME: as we insert all the pages now then no .fault handler must
* be called, so don't provide one
*/
ret = vm_map_pages(vma, xen_obj->pages, xen_obj->num_pages);
if (ret < 0)
DRM_ERROR("Failed to map pages into vma: %d\n", ret);
return ret;
}
static const struct vm_operations_struct xen_drm_drv_vm_ops = {
.open = drm_gem_vm_open,
.close = drm_gem_vm_close,
};
static const struct drm_gem_object_funcs xen_drm_front_gem_object_funcs = {
.free = xen_drm_front_gem_object_free,
.get_sg_table = xen_drm_front_gem_get_sg_table,
.vmap = xen_drm_front_gem_prime_vmap,
.vunmap = xen_drm_front_gem_prime_vunmap,
.mmap = xen_drm_front_gem_object_mmap,
.vm_ops = &xen_drm_drv_vm_ops,
};
static struct xen_gem_object *gem_create_obj(struct drm_device *dev,
size_t size)
{
struct xen_gem_object *xen_obj;
int ret;
xen_obj = kzalloc(sizeof(*xen_obj), GFP_KERNEL);
if (!xen_obj)
return ERR_PTR(-ENOMEM);
xen_obj->base.funcs = &xen_drm_front_gem_object_funcs;
ret = drm_gem_object_init(dev, &xen_obj->base, size);
if (ret < 0) {
kfree(xen_obj);
return ERR_PTR(ret);
}
return xen_obj;
}
static struct xen_gem_object *gem_create(struct drm_device *dev, size_t size)
{
struct xen_drm_front_drm_info *drm_info = dev->dev_private;
struct xen_gem_object *xen_obj;
int ret;
size = round_up(size, PAGE_SIZE);
xen_obj = gem_create_obj(dev, size);
if (IS_ERR(xen_obj))
return xen_obj;
if (drm_info->front_info->cfg.be_alloc) {
/*
* backend will allocate space for this buffer, so
* only allocate array of pointers to pages
*/
ret = gem_alloc_pages_array(xen_obj, size);
if (ret < 0)
goto fail;
/*
* allocate ballooned pages which will be used to map
* grant references provided by the backend
*/
ret = xen_alloc_unpopulated_pages(xen_obj->num_pages,
xen_obj->pages);
if (ret < 0) {
DRM_ERROR("Cannot allocate %zu ballooned pages: %d\n",
xen_obj->num_pages, ret);
gem_free_pages_array(xen_obj);
goto fail;
}
xen_obj->be_alloc = true;
return xen_obj;
}
/*
* need to allocate backing pages now, so we can share those
* with the backend
*/
xen_obj->num_pages = DIV_ROUND_UP(size, PAGE_SIZE);
xen_obj->pages = drm_gem_get_pages(&xen_obj->base);
if (IS_ERR(xen_obj->pages)) {
ret = PTR_ERR(xen_obj->pages);
xen_obj->pages = NULL;
goto fail;
}
return xen_obj;
fail:
DRM_ERROR("Failed to allocate buffer with size %zu\n", size);
return ERR_PTR(ret);
}
struct drm_gem_object *xen_drm_front_gem_create(struct drm_device *dev,
size_t size)
{
struct xen_gem_object *xen_obj;
xen_obj = gem_create(dev, size);
if (IS_ERR(xen_obj))
return ERR_CAST(xen_obj);
return &xen_obj->base;
}
void xen_drm_front_gem_free_object_unlocked(struct drm_gem_object *gem_obj)
{
struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
if (xen_obj->base.import_attach) {
drm_prime_gem_destroy(&xen_obj->base, xen_obj->sgt_imported);
gem_free_pages_array(xen_obj);
} else {
if (xen_obj->pages) {
if (xen_obj->be_alloc) {
xen_free_unpopulated_pages(xen_obj->num_pages,
xen_obj->pages);
gem_free_pages_array(xen_obj);
} else {
drm_gem_put_pages(&xen_obj->base,
xen_obj->pages, true, false);
}
}
}
drm_gem_object_release(gem_obj);
kfree(xen_obj);
}
struct page **xen_drm_front_gem_get_pages(struct drm_gem_object *gem_obj)
{
struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
return xen_obj->pages;
}
struct sg_table *xen_drm_front_gem_get_sg_table(struct drm_gem_object *gem_obj)
{
struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
if (!xen_obj->pages)
return ERR_PTR(-ENOMEM);
return drm_prime_pages_to_sg(gem_obj->dev,
xen_obj->pages, xen_obj->num_pages);
}
struct drm_gem_object *
xen_drm_front_gem_import_sg_table(struct drm_device *dev,
struct dma_buf_attachment *attach,
struct sg_table *sgt)
{
struct xen_drm_front_drm_info *drm_info = dev->dev_private;
struct xen_gem_object *xen_obj;
size_t size;
int ret;
size = attach->dmabuf->size;
xen_obj = gem_create_obj(dev, size);
if (IS_ERR(xen_obj))
return ERR_CAST(xen_obj);
ret = gem_alloc_pages_array(xen_obj, size);
if (ret < 0)
return ERR_PTR(ret);
xen_obj->sgt_imported = sgt;
ret = drm_prime_sg_to_page_array(sgt, xen_obj->pages,
xen_obj->num_pages);
if (ret < 0)
return ERR_PTR(ret);
ret = xen_drm_front_dbuf_create(drm_info->front_info,
xen_drm_front_dbuf_to_cookie(&xen_obj->base),
0, 0, 0, size, sgt->sgl->offset,
xen_obj->pages);
if (ret < 0)
return ERR_PTR(ret);
DRM_DEBUG("Imported buffer of size %zu with nents %u\n",
size, sgt->orig_nents);
return &xen_obj->base;
}
int xen_drm_front_gem_prime_vmap(struct drm_gem_object *gem_obj,
struct iosys_map *map)
{
struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
void *vaddr;
if (!xen_obj->pages)
return -ENOMEM;
/* Please see comment in gem_mmap_obj on mapping and attributes. */
vaddr = vmap(xen_obj->pages, xen_obj->num_pages,
VM_MAP, PAGE_KERNEL);
if (!vaddr)
return -ENOMEM;
iosys_map_set_vaddr(map, vaddr);
return 0;
}
void xen_drm_front_gem_prime_vunmap(struct drm_gem_object *gem_obj,
struct iosys_map *map)
{
vunmap(map->vaddr);
}
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