[PATCH V1] accel/amdxdna: Support user space allocated buffer
Lizhi Hou
lizhi.hou at amd.com
Mon Jul 7 19:38:13 UTC 2025
Enhance DRM_IOCTL_AMDXDNA_CREATE_BO to accept user space allocated
buffer pointer. The buffer pages will be pinned in memory. Unless
the CAP_IPC_LOCK is enabled for the application process, the total
pinned memory can not beyond rlimit_memlock.
Signed-off-by: Lizhi Hou <lizhi.hou at amd.com>
---
drivers/accel/amdxdna/Makefile | 1 +
drivers/accel/amdxdna/amdxdna_gem.c | 139 +++++++++++++---
drivers/accel/amdxdna/amdxdna_ubuf.c | 232 +++++++++++++++++++++++++++
drivers/accel/amdxdna/amdxdna_ubuf.h | 19 +++
include/uapi/drm/amdxdna_accel.h | 25 +++
5 files changed, 391 insertions(+), 25 deletions(-)
create mode 100644 drivers/accel/amdxdna/amdxdna_ubuf.c
create mode 100644 drivers/accel/amdxdna/amdxdna_ubuf.h
diff --git a/drivers/accel/amdxdna/Makefile b/drivers/accel/amdxdna/Makefile
index 0e9adf6890a0..6797dac65efa 100644
--- a/drivers/accel/amdxdna/Makefile
+++ b/drivers/accel/amdxdna/Makefile
@@ -15,6 +15,7 @@ amdxdna-y := \
amdxdna_mailbox_helper.o \
amdxdna_pci_drv.o \
amdxdna_sysfs.o \
+ amdxdna_ubuf.o \
npu1_regs.o \
npu2_regs.o \
npu4_regs.o \
diff --git a/drivers/accel/amdxdna/amdxdna_gem.c b/drivers/accel/amdxdna/amdxdna_gem.c
index 0f85a0105178..d407a36eb412 100644
--- a/drivers/accel/amdxdna/amdxdna_gem.c
+++ b/drivers/accel/amdxdna/amdxdna_gem.c
@@ -18,6 +18,7 @@
#include "amdxdna_ctx.h"
#include "amdxdna_gem.h"
#include "amdxdna_pci_drv.h"
+#include "amdxdna_ubuf.h"
#define XDNA_MAX_CMD_BO_SIZE SZ_32K
@@ -296,7 +297,7 @@ static int amdxdna_insert_pages(struct amdxdna_gem_obj *abo,
vma->vm_private_data = NULL;
vma->vm_ops = NULL;
- ret = dma_buf_mmap(to_gobj(abo)->dma_buf, vma, 0);
+ ret = dma_buf_mmap(abo->dma_buf, vma, 0);
if (ret) {
XDNA_ERR(xdna, "Failed to mmap dma buf %d", ret);
return ret;
@@ -391,10 +392,47 @@ static const struct dma_buf_ops amdxdna_dmabuf_ops = {
.vunmap = drm_gem_dmabuf_vunmap,
};
+static int amdxdna_gem_obj_vmap(struct drm_gem_object *obj, struct iosys_map *map)
+{
+ struct amdxdna_gem_obj *abo = to_xdna_obj(obj);
+
+ iosys_map_clear(map);
+
+ dma_resv_assert_held(obj->resv);
+
+ if (is_import_bo(abo))
+ dma_buf_vmap(abo->dma_buf, map);
+ else
+ drm_gem_shmem_object_vmap(obj, map);
+
+ if (!map->vaddr)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void amdxdna_gem_obj_vunmap(struct drm_gem_object *obj, struct iosys_map *map)
+{
+ struct amdxdna_gem_obj *abo = to_xdna_obj(obj);
+
+ dma_resv_assert_held(obj->resv);
+
+ if (is_import_bo(abo))
+ dma_buf_vunmap(abo->dma_buf, map);
+ else
+ drm_gem_shmem_object_vunmap(obj, map);
+}
+
static struct dma_buf *amdxdna_gem_prime_export(struct drm_gem_object *gobj, int flags)
{
+ struct amdxdna_gem_obj *abo = to_xdna_obj(gobj);
DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+ if (abo->dma_buf) {
+ get_dma_buf(abo->dma_buf);
+ return abo->dma_buf;
+ }
+
exp_info.ops = &amdxdna_dmabuf_ops;
exp_info.size = gobj->size;
exp_info.flags = flags;
@@ -451,8 +489,8 @@ static const struct drm_gem_object_funcs amdxdna_gem_shmem_funcs = {
.pin = drm_gem_shmem_object_pin,
.unpin = drm_gem_shmem_object_unpin,
.get_sg_table = drm_gem_shmem_object_get_sg_table,
- .vmap = drm_gem_shmem_object_vmap,
- .vunmap = drm_gem_shmem_object_vunmap,
+ .vmap = amdxdna_gem_obj_vmap,
+ .vunmap = amdxdna_gem_obj_vunmap,
.mmap = amdxdna_gem_obj_mmap,
.vm_ops = &drm_gem_shmem_vm_ops,
.export = amdxdna_gem_prime_export,
@@ -494,6 +532,68 @@ amdxdna_gem_create_object_cb(struct drm_device *dev, size_t size)
return to_gobj(abo);
}
+static struct amdxdna_gem_obj *
+amdxdna_gem_create_shmem_object(struct drm_device *dev, size_t size)
+{
+ struct drm_gem_shmem_object *shmem = drm_gem_shmem_create(dev, size);
+
+ if (IS_ERR(shmem))
+ return ERR_CAST(shmem);
+
+ shmem->map_wc = false;
+ return to_xdna_obj(&shmem->base);
+}
+
+static struct amdxdna_gem_obj *
+amdxdna_gem_create_ubuf_object(struct drm_device *dev, struct amdxdna_drm_create_bo *args)
+{
+ struct amdxdna_dev *xdna = to_xdna_dev(dev);
+ enum amdxdna_ubuf_flag flags = 0;
+ struct amdxdna_drm_va_tbl va_tbl;
+ struct drm_gem_object *gobj;
+ struct dma_buf *dma_buf;
+
+ if (copy_from_user(&va_tbl, u64_to_user_ptr(args->vaddr), sizeof(va_tbl))) {
+ XDNA_DBG(xdna, "Access va table failed");
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (va_tbl.num_entries) {
+ if (args->type == AMDXDNA_BO_CMD)
+ flags |= AMDXDNA_UBUF_FLAG_MAP_DMA;
+
+ dma_buf = amdxdna_get_ubuf(dev, flags, va_tbl.num_entries,
+ u64_to_user_ptr(args->vaddr + sizeof(va_tbl)));
+ } else {
+ dma_buf = dma_buf_get(va_tbl.dmabuf_fd);
+ }
+
+ if (IS_ERR(dma_buf))
+ return ERR_CAST(dma_buf);
+
+ gobj = amdxdna_gem_prime_import(dev, dma_buf);
+ if (IS_ERR(gobj)) {
+ dma_buf_put(dma_buf);
+ return ERR_CAST(gobj);
+ }
+
+ dma_buf_put(dma_buf);
+
+ return to_xdna_obj(gobj);
+}
+
+static struct amdxdna_gem_obj *
+amdxdna_gem_create_object(struct drm_device *dev,
+ struct amdxdna_drm_create_bo *args)
+{
+ size_t aligned_sz = PAGE_ALIGN(args->size);
+
+ if (args->vaddr)
+ return amdxdna_gem_create_ubuf_object(dev, args);
+
+ return amdxdna_gem_create_shmem_object(dev, aligned_sz);
+}
+
struct drm_gem_object *
amdxdna_gem_prime_import(struct drm_device *dev, struct dma_buf *dma_buf)
{
@@ -545,16 +645,12 @@ amdxdna_drm_alloc_shmem(struct drm_device *dev,
struct drm_file *filp)
{
struct amdxdna_client *client = filp->driver_priv;
- struct drm_gem_shmem_object *shmem;
struct amdxdna_gem_obj *abo;
- shmem = drm_gem_shmem_create(dev, args->size);
- if (IS_ERR(shmem))
- return ERR_CAST(shmem);
-
- shmem->map_wc = false;
+ abo = amdxdna_gem_create_object(dev, args);
+ if (IS_ERR(abo))
+ return ERR_CAST(abo);
- abo = to_xdna_obj(&shmem->base);
abo->client = client;
abo->type = AMDXDNA_BO_SHMEM;
@@ -569,7 +665,6 @@ amdxdna_drm_create_dev_heap(struct drm_device *dev,
struct amdxdna_client *client = filp->driver_priv;
struct iosys_map map = IOSYS_MAP_INIT_VADDR(NULL);
struct amdxdna_dev *xdna = to_xdna_dev(dev);
- struct drm_gem_shmem_object *shmem;
struct amdxdna_gem_obj *abo;
int ret;
@@ -586,14 +681,12 @@ amdxdna_drm_create_dev_heap(struct drm_device *dev,
goto mm_unlock;
}
- shmem = drm_gem_shmem_create(dev, args->size);
- if (IS_ERR(shmem)) {
- ret = PTR_ERR(shmem);
+ abo = amdxdna_gem_create_object(dev, args);
+ if (IS_ERR(abo)) {
+ ret = PTR_ERR(abo);
goto mm_unlock;
}
- shmem->map_wc = false;
- abo = to_xdna_obj(&shmem->base);
abo->type = AMDXDNA_BO_DEV_HEAP;
abo->client = client;
abo->mem.dev_addr = client->xdna->dev_info->dev_mem_base;
@@ -657,7 +750,6 @@ amdxdna_drm_create_cmd_bo(struct drm_device *dev,
{
struct iosys_map map = IOSYS_MAP_INIT_VADDR(NULL);
struct amdxdna_dev *xdna = to_xdna_dev(dev);
- struct drm_gem_shmem_object *shmem;
struct amdxdna_gem_obj *abo;
int ret;
@@ -671,12 +763,9 @@ amdxdna_drm_create_cmd_bo(struct drm_device *dev,
return ERR_PTR(-EINVAL);
}
- shmem = drm_gem_shmem_create(dev, args->size);
- if (IS_ERR(shmem))
- return ERR_CAST(shmem);
-
- shmem->map_wc = false;
- abo = to_xdna_obj(&shmem->base);
+ abo = amdxdna_gem_create_object(dev, args);
+ if (IS_ERR(abo))
+ return ERR_CAST(abo);
abo->type = AMDXDNA_BO_CMD;
abo->client = filp->driver_priv;
@@ -691,7 +780,7 @@ amdxdna_drm_create_cmd_bo(struct drm_device *dev,
return abo;
release_obj:
- drm_gem_shmem_free(shmem);
+ drm_gem_object_put(to_gobj(abo));
return ERR_PTR(ret);
}
@@ -702,7 +791,7 @@ int amdxdna_drm_create_bo_ioctl(struct drm_device *dev, void *data, struct drm_f
struct amdxdna_gem_obj *abo;
int ret;
- if (args->flags || args->vaddr || !args->size)
+ if (args->flags)
return -EINVAL;
XDNA_DBG(xdna, "BO arg type %d vaddr 0x%llx size 0x%llx flags 0x%llx",
diff --git a/drivers/accel/amdxdna/amdxdna_ubuf.c b/drivers/accel/amdxdna/amdxdna_ubuf.c
new file mode 100644
index 000000000000..c19167ecd963
--- /dev/null
+++ b/drivers/accel/amdxdna/amdxdna_ubuf.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2025, Advanced Micro Devices, Inc.
+ */
+
+#include <drm/amdxdna_accel.h>
+#include <drm/drm_device.h>
+#include <drm/drm_print.h>
+#include <linux/dma-buf.h>
+#include <linux/pagemap.h>
+#include <linux/vmalloc.h>
+
+#include "amdxdna_pci_drv.h"
+#include "amdxdna_ubuf.h"
+
+struct amdxdna_ubuf_priv {
+ struct page **pages;
+ u64 nr_pages;
+ enum amdxdna_ubuf_flag flags;
+ struct mm_struct *mm;
+};
+
+static struct sg_table *amdxdna_ubuf_map(struct dma_buf_attachment *attach,
+ enum dma_data_direction direction)
+{
+ struct amdxdna_ubuf_priv *ubuf = attach->dmabuf->priv;
+ struct sg_table *sg;
+ int ret;
+
+ sg = kzalloc(sizeof(*sg), GFP_KERNEL);
+ if (!sg)
+ return ERR_PTR(-ENOMEM);
+
+ ret = sg_alloc_table_from_pages(sg, ubuf->pages, ubuf->nr_pages, 0,
+ ubuf->nr_pages << PAGE_SHIFT, GFP_KERNEL);
+ if (ret)
+ return ERR_PTR(ret);
+
+ if (ubuf->flags & AMDXDNA_UBUF_FLAG_MAP_DMA) {
+ ret = dma_map_sgtable(attach->dev, sg, direction, 0);
+ if (ret)
+ return ERR_PTR(ret);
+ }
+
+ return sg;
+}
+
+static void amdxdna_ubuf_unmap(struct dma_buf_attachment *attach,
+ struct sg_table *sg,
+ enum dma_data_direction direction)
+{
+ struct amdxdna_ubuf_priv *ubuf = attach->dmabuf->priv;
+
+ if (ubuf->flags & AMDXDNA_UBUF_FLAG_MAP_DMA)
+ dma_unmap_sgtable(attach->dev, sg, direction, 0);
+
+ sg_free_table(sg);
+ kfree(sg);
+}
+
+static void amdxdna_ubuf_release(struct dma_buf *dbuf)
+{
+ struct amdxdna_ubuf_priv *ubuf = dbuf->priv;
+
+ unpin_user_pages(ubuf->pages, ubuf->nr_pages);
+ kvfree(ubuf->pages);
+ atomic64_sub(ubuf->nr_pages, &ubuf->mm->pinned_vm);
+ mmdrop(ubuf->mm);
+ kfree(ubuf);
+}
+
+static vm_fault_t amdxdna_ubuf_vm_fault(struct vm_fault *vmf)
+{
+ struct vm_area_struct *vma = vmf->vma;
+ struct amdxdna_ubuf_priv *ubuf;
+ unsigned long pfn;
+ pgoff_t pgoff;
+
+ ubuf = vma->vm_private_data;
+ pgoff = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
+
+ pfn = page_to_pfn(ubuf->pages[pgoff]);
+ return vmf_insert_pfn(vma, vmf->address, pfn);
+}
+
+static const struct vm_operations_struct amdxdna_ubuf_vm_ops = {
+ .fault = amdxdna_ubuf_vm_fault,
+};
+
+static int amdxdna_ubuf_mmap(struct dma_buf *dbuf, struct vm_area_struct *vma)
+{
+ struct amdxdna_ubuf_priv *ubuf = dbuf->priv;
+
+ vma->vm_ops = &amdxdna_ubuf_vm_ops;
+ vma->vm_private_data = ubuf;
+ vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP);
+
+ return 0;
+}
+
+static int amdxdna_ubuf_vmap(struct dma_buf *dbuf, struct iosys_map *map)
+{
+ struct amdxdna_ubuf_priv *ubuf = dbuf->priv;
+ void *kva;
+
+ kva = vmap(ubuf->pages, ubuf->nr_pages, VM_MAP, PAGE_KERNEL);
+ if (!kva)
+ return -EINVAL;
+
+ iosys_map_set_vaddr(map, kva);
+ return 0;
+}
+
+static void amdxdna_ubuf_vunmap(struct dma_buf *dbuf, struct iosys_map *map)
+{
+ vunmap(map->vaddr);
+}
+
+static const struct dma_buf_ops amdxdna_ubuf_dmabuf_ops = {
+ .map_dma_buf = amdxdna_ubuf_map,
+ .unmap_dma_buf = amdxdna_ubuf_unmap,
+ .release = amdxdna_ubuf_release,
+ .mmap = amdxdna_ubuf_mmap,
+ .vmap = amdxdna_ubuf_vmap,
+ .vunmap = amdxdna_ubuf_vunmap,
+};
+
+struct dma_buf *amdxdna_get_ubuf(struct drm_device *dev,
+ enum amdxdna_ubuf_flag flags,
+ u32 num_entries, void __user *va_entries)
+{
+ struct amdxdna_dev *xdna = to_xdna_dev(dev);
+ unsigned long lock_limit, new_pinned;
+ struct amdxdna_drm_va_entry *va_ent;
+ struct amdxdna_ubuf_priv *ubuf;
+ u32 npages, start = 0;
+ struct dma_buf *dbuf;
+ int i, ret;
+ DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+ if (!can_do_mlock())
+ return ERR_PTR(-EPERM);
+
+ ubuf = kzalloc(sizeof(*ubuf), GFP_KERNEL);
+ if (!ubuf)
+ return ERR_PTR(-ENOMEM);
+
+ ubuf->flags = flags;
+ ubuf->mm = current->mm;
+ mmgrab(ubuf->mm);
+
+ va_ent = kvcalloc(num_entries, sizeof(*va_ent), GFP_KERNEL);
+ if (!va_ent) {
+ ret = -ENOMEM;
+ goto free_ubuf;
+ }
+
+ if (copy_from_user(va_ent, va_entries, sizeof(*va_ent) * num_entries)) {
+ XDNA_DBG(xdna, "Access va entries failed");
+ ret = -EINVAL;
+ goto free_ent;
+ }
+
+ for (i = 0, exp_info.size = 0; i < num_entries; i++) {
+ if ((va_ent[i].vaddr & (PAGE_SIZE - 1)) ||
+ (va_ent[i].len & (PAGE_SIZE - 1))) {
+ XDNA_ERR(xdna, "Invalid address or len %llx, %llx",
+ va_ent[i].vaddr, va_ent[i].len);
+ ret = -EINVAL;
+ goto free_ent;
+ }
+
+ exp_info.size += va_ent[i].len;
+ }
+
+ ubuf->nr_pages = exp_info.size >> PAGE_SHIFT;
+ lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+ new_pinned = atomic64_add_return(ubuf->nr_pages, &ubuf->mm->pinned_vm);
+ if (new_pinned > lock_limit && !capable(CAP_IPC_LOCK)) {
+ XDNA_DBG(xdna, "New pin %ld, limit %ld, cap %d",
+ new_pinned, lock_limit, capable(CAP_IPC_LOCK));
+ ret = -ENOMEM;
+ goto sub_pin_cnt;
+ }
+
+ ubuf->pages = kvmalloc_array(ubuf->nr_pages, sizeof(*ubuf->pages), GFP_KERNEL);
+ if (!ubuf->pages) {
+ ret = -ENOMEM;
+ goto sub_pin_cnt;
+ }
+
+ for (i = 0; i < num_entries; i++) {
+ npages = va_ent[i].len >> PAGE_SHIFT;
+
+ ret = pin_user_pages_fast(va_ent[i].vaddr, npages,
+ FOLL_WRITE | FOLL_LONGTERM,
+ &ubuf->pages[start]);
+ if (ret < 0 || ret != npages) {
+ ret = -ENOMEM;
+ XDNA_ERR(xdna, "Failed to pin pages ret %d", ret);
+ goto destroy_pages;
+ }
+
+ start += ret;
+ }
+
+ exp_info.ops = &amdxdna_ubuf_dmabuf_ops;
+ exp_info.priv = ubuf;
+ exp_info.flags = O_RDWR;
+
+ dbuf = dma_buf_export(&exp_info);
+ if (IS_ERR(dbuf)) {
+ ret = PTR_ERR(dbuf);
+ goto destroy_pages;
+ }
+ kvfree(va_ent);
+
+ return dbuf;
+
+destroy_pages:
+ if (start)
+ unpin_user_pages(ubuf->pages, start);
+ kvfree(ubuf->pages);
+sub_pin_cnt:
+ atomic64_sub(ubuf->nr_pages, &ubuf->mm->pinned_vm);
+free_ent:
+ kvfree(va_ent);
+free_ubuf:
+ mmdrop(ubuf->mm);
+ kfree(ubuf);
+ return ERR_PTR(ret);
+}
diff --git a/drivers/accel/amdxdna/amdxdna_ubuf.h b/drivers/accel/amdxdna/amdxdna_ubuf.h
new file mode 100644
index 000000000000..e5cb3bdb3ec9
--- /dev/null
+++ b/drivers/accel/amdxdna/amdxdna_ubuf.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2025, Advanced Micro Devices, Inc.
+ */
+#ifndef _AMDXDNA_UBUF_H_
+#define _AMDXDNA_UBUF_H_
+
+#include <drm/drm_device.h>
+#include <linux/dma-buf.h>
+
+enum amdxdna_ubuf_flag {
+ AMDXDNA_UBUF_FLAG_MAP_DMA = 1,
+};
+
+struct dma_buf *amdxdna_get_ubuf(struct drm_device *dev,
+ enum amdxdna_ubuf_flag flags,
+ u32 num_entries, void __user *va_entries);
+
+#endif /* _AMDXDNA_UBUF_H_ */
diff --git a/include/uapi/drm/amdxdna_accel.h b/include/uapi/drm/amdxdna_accel.h
index a706ead39082..ce523e9ccc52 100644
--- a/include/uapi/drm/amdxdna_accel.h
+++ b/include/uapi/drm/amdxdna_accel.h
@@ -153,6 +153,31 @@ enum amdxdna_bo_type {
AMDXDNA_BO_CMD,
};
+/**
+ * struct amdxdna_drm_va_entry
+ * @vaddr: Virtual address.
+ * @len: Size of entry.
+ */
+struct amdxdna_drm_va_entry {
+ __u64 vaddr;
+ __u64 len;
+};
+
+/**
+ * struct amdxdna_drm_va_tbl
+ * @dmabuf_fd: The fd of dmabuf.
+ * @num_entries: Number of va entries.
+ * @va_entries: Array of va entries.
+ *
+ * The input can be either a dmabuf fd or a virtual address entry table.
+ * When dmabuf_fd is used, num_entries must be zero.
+ */
+struct amdxdna_drm_va_tbl {
+ __s32 dmabuf_fd;
+ __u32 num_entries;
+ struct amdxdna_drm_va_entry va_entries[];
+};
+
/**
* struct amdxdna_drm_create_bo - Create a buffer object.
* @flags: Buffer flags. MBZ.
--
2.34.1
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