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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: kzoYE8GpqCeabqH8c1TBDN73YB9XHGUo4nyAuqhnfGvUB0ZHco5jQVdOpTytwAOIwvW4PYSQgQzcb9f+F+3tj68i/yDPIpmZffdzb/cYmU0r5gjWiNBskLzU6UywlfMO2bj1u2lJMOO7om89KIIpJIe9xP0T/l6AvU/+8MV1XyS6aeTEcggUQQpSWLXDgrt0DcOLsyyWBX+ckynhg2ZtLW4JFSrHSTE5p/tcejNmCWEi/dgd+df09cnp5yAPLhrpmJO7ilxhsannvOyWKiK6xoMFrK+H1HoYMJgpQbK5uRvQWQi/zu9rYDAX855UP9N1VFxovWlD4IjPcJ/+fXwAIYjbxbTup5EscCKAZkFaf26GhPsJpjy8AKerbUfFbcf2Rt+66yRWr//lYiDH+kXjpPq4kwXcY5tug4RQNCQaoXfwdhPJwIeb9USLLnwqKzuk X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Sep 2026 22:39:54.3908 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: debf4ee5-e7fd-4e74-a70f-08df0f8c6f23 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BN1PEPF00018546.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR12MB5628 On 9/10/2026 Thu 14:13, Lizhi Hou wrote: > handle_mm_fault() must not be called from the mmap callback because > the VMA has not yet been linked. The handle_mm_fault() API contract > assumes that the VMA is already linked. > > Remove the handle_mm_fault() call from the mmap callback. For imported > BOs, mark the mapping as invalid and rely on the first command submission > to fault in the pages. > > For shmem BOs, set the VM_MIXEDMAP flag and use vm_insert_pages(). > Implement amdxdna_gem_mixed_vm_ops to handle the page faults. > > Fixes: e486147c912f ("accel/amdxdna: Add BO import and export") > Signed-off-by: Lizhi Hou Reviewed-by: Max Zhen > --- > 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 > #include > #include > +#include > #include > > #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, > }; >