---
v2 & v3:
Fix sashiko comment.
drivers/accel/amdxdna/amdxdna_gem.c | 151 ++++++++++++++++++++++------
1 file changed, 118 insertions(+), 33 deletions(-)
diff --git a/drivers/accel/amdxdna/amdxdna_gem.c
b/drivers/accel/amdxdna/amdxdna_gem.c
index 0d165b66c1fc..a12a762b3a6b 100644
--- a/drivers/accel/amdxdna/amdxdna_gem.c
+++ b/drivers/accel/amdxdna/amdxdna_gem.c
@@ -14,6 +14,7 @@
#include <linux/dma-direct.h>
#include <linux/iosys-map.h>
#include <linux/pagemap.h>
+#include <linux/swap.h>
#include <linux/vmalloc.h>
#include "amdxdna_cbuf.h"
@@ -490,16 +491,16 @@ static int amdxdna_insert_pages(struct
amdxdna_gem_obj *abo,
{
struct amdxdna_dev *xdna = to_xdna_dev(to_gobj(abo)->dev);
unsigned long num_pages = vma_pages(vma);
- unsigned long offset = 0;
int ret;
- if (!is_import_bo(abo)) {
- ret = drm_gem_shmem_mmap(&abo->base, vma);
- if (ret) {
- XDNA_ERR(xdna, "Failed shmem mmap %d", ret);
- return ret;
- }
- } else {
+ /*
+ * Until today there is not any use case to mmap with non-zero
+ * offset. Put an explicit check here.
+ */
+ if (vma->vm_pgoff - drm_vma_node_start(&to_gobj(abo)->vma_node))
+ return -EINVAL;
+
+ if (is_import_bo(abo)) {
vma->vm_private_data = NULL;
vma->vm_ops = NULL;
ret = dma_buf_mmap(abo->dma_buf, vma, 0);
@@ -508,23 +509,28 @@ static int amdxdna_insert_pages(struct
amdxdna_gem_obj *abo,
return ret;
}
+ amdxdna_mark_mapp_invalid(abo, vma);
+
/* Drop the reference drm_gem_mmap_obj() acquired.*/
drm_gem_object_put(to_gobj(abo));
+ return 0;
}
- do {
- vm_fault_t fault_ret;
-
- fault_ret = handle_mm_fault(vma, vma->vm_start + offset,
- FAULT_FLAG_WRITE, NULL);
- if (fault_ret & VM_FAULT_ERROR) {
- XDNA_ERR(xdna, "Fault in page failed");
- amdxdna_mark_mapp_invalid(abo, vma);
- break;
- }
+ ret = drm_gem_shmem_mmap(&abo->base, vma);
+ if (ret) {
+ XDNA_ERR(xdna, "Failed shmem mmap %d", ret);
+ return ret;
+ }
- offset += PAGE_SIZE;
- } while (--num_pages);
+ vm_flags_mod(vma, VM_MIXEDMAP, VM_PFNMAP);
+ ret = vm_insert_pages(vma, vma->vm_start, abo->base.pages,
&num_pages);
+ if (ret) {
+ XDNA_ERR(xdna, "Failed to insert pages %d", ret);
+ dma_resv_lock(to_gobj(abo)->resv, NULL);
+ drm_gem_shmem_put_pages_locked(&abo->base);
+ dma_resv_unlock(to_gobj(abo)->resv);
+ return ret;
+ }
return 0;
}
@@ -536,6 +542,10 @@ static int amdxdna_gem_obj_mmap(struct
drm_gem_object *gobj,
struct amdxdna_gem_obj *abo = to_xdna_obj(gobj);
int ret;
+ XDNA_DBG(xdna, "BO map_offset 0x%llx type %d userptr 0x%lx
size 0x%lx",
+ drm_vma_node_offset_addr(&gobj->vma_node), abo->type,
+ vma->vm_start, gobj->size);
+
ret = amdxdna_hmm_register(abo, vma);
if (ret)
return ret;
@@ -546,9 +556,6 @@ static int amdxdna_gem_obj_mmap(struct
drm_gem_object *gobj,
goto hmm_unreg;
}
- XDNA_DBG(xdna, "BO map_offset 0x%llx type %d userptr 0x%lx
size 0x%lx",
- drm_vma_node_offset_addr(&gobj->vma_node), abo->type,
- vma->vm_start, gobj->size);
return 0;
hmm_unreg:
@@ -556,14 +563,99 @@ static int amdxdna_gem_obj_mmap(struct
drm_gem_object *gobj,
return ret;
}
+/*
+ * VM operations for amdxdna shmem VMAs that use VM_MIXEDMAP.
+ *
+ * drm_gem_shmem_vm_ops cannot be used on VM_MIXEDMAP VMAs because
its fault
+ * handler calls vmf_insert_pfn() → vmf_insert_pfn_prot() which
contains:
+ * BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn))
+ * All amdxdna shmem pages are ordinary struct pages so pfn_valid()
is always
+ * true, making the combination fatal.
+ *
+ * These ops use vmf_insert_page() (struct-page based) instead,
which is the
+ * correct API for VM_MIXEDMAP VMAs backed by real struct pages.
The open and
+ * close handlers replicate drm_gem_shmem_vm_open/close using only
exported
+ * symbols.
+ */
+static vm_fault_t amdxdna_gem_mixedmap_fault(struct vm_fault *vmf)
+{
+ struct vm_area_struct *vma = vmf->vma;
+ struct drm_gem_object *gobj = vma->vm_private_data;
+ struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(gobj);
+ loff_t num_pages = gobj->size >> PAGE_SHIFT;
+ vm_fault_t ret = VM_FAULT_SIGBUS;
+ pgoff_t page_offset;
+ struct page *page;
+
+ /*
+ * Partial free of vma is unexpected. Otherwise, the wrong page
+ * will be faulted in and the user application may crash itself.
+ */
+ page_offset = vmf->pgoff - vma->vm_pgoff;
+
+ dma_resv_lock(gobj->resv, NULL);
+
+ if (!shmem->pages || shmem->madv < 0 || page_offset >= num_pages)
+ goto out;
+
+ page = shmem->pages[page_offset];
+ if (WARN_ON_ONCE(!page))
+ goto out;
+
+ /*
+ * Use vmf_insert_page() (struct-page path) not vmf_insert_pfn()
+ * (PFN path) because this VMA carries VM_MIXEDMAP.
+ */
+ ret = vmf_insert_page(vma, vmf->address, page);
+ if (ret == VM_FAULT_NOPAGE)
+ folio_mark_accessed(page_folio(page));
+
+out:
+ dma_resv_unlock(gobj->resv);
+ return ret;
+}
+
+static void amdxdna_gem_mixedmap_vm_open(struct vm_area_struct *vma)
+{
+ struct drm_gem_object *gobj = vma->vm_private_data;
+ struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(gobj);
+
+ /*
+ * Bump pages_use_count so the page array stays alive for the new
+ * mapping copy created by fork(). Mirrors
drm_gem_shmem_vm_open().
+ */
+ dma_resv_lock(gobj->resv, NULL);
+ drm_WARN_ON_ONCE(gobj->dev,
!refcount_inc_not_zero(&shmem->pages_use_count));
+ dma_resv_unlock(gobj->resv);
+
+ drm_gem_vm_open(vma);
+}
+
+static void amdxdna_gem_mixedmap_vm_close(struct vm_area_struct *vma)
+{
+ struct drm_gem_object *gobj = vma->vm_private_data;
+ struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(gobj);
+
+ dma_resv_lock(gobj->resv, NULL);
+ drm_gem_shmem_put_pages_locked(shmem);
+ dma_resv_unlock(gobj->resv);
+
+ drm_gem_vm_close(vma);
+}
+
+static const struct vm_operations_struct amdxdna_gem_mixedmap_vm_ops
= {
+ .fault = amdxdna_gem_mixedmap_fault,
+ .open = amdxdna_gem_mixedmap_vm_open,
+ .close = amdxdna_gem_mixedmap_vm_close,
+};
+
static int amdxdna_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct
vm_area_struct *vma)
{
struct drm_gem_object *gobj = dma_buf->priv;
struct amdxdna_gem_obj *abo = to_xdna_obj(gobj);
- unsigned long num_pages = vma_pages(vma);
int ret;
- vma->vm_ops = &drm_gem_shmem_vm_ops;
+ vma->vm_ops = &amdxdna_gem_mixedmap_vm_ops;
vma->vm_private_data = gobj;
drm_gem_object_get(gobj);
@@ -573,16 +665,9 @@ static int amdxdna_gem_dmabuf_mmap(struct
dma_buf *dma_buf, struct vm_area_struc
/* The buffer is based on memory pages. Fix the flag. */
vm_flags_mod(vma, VM_MIXEDMAP, VM_PFNMAP);
- ret = vm_insert_pages(vma, vma->vm_start, abo->base.pages,
- &num_pages);
- if (ret)
- goto close_vma;
return 0;
-close_vma:
- vma->vm_ops->close(vma);
- return ret;
put_obj:
drm_gem_object_put(gobj);
return ret;
@@ -878,7 +963,7 @@ static const struct drm_gem_object_funcs
amdxdna_gem_shmem_funcs = {
.vmap = amdxdna_gem_obj_vmap,
.vunmap = amdxdna_gem_obj_vunmap,
.mmap = amdxdna_gem_obj_mmap,
- .vm_ops = &drm_gem_shmem_vm_ops,
+ .vm_ops = &amdxdna_gem_mixedmap_vm_ops,
.export = amdxdna_gem_prime_export,
};
