drm/i915/ttm: only fault WILLNEED objects

Don't attempt to fault and re-populate purged objects. By some fluke
this passes the dontneed-after-mmap IGT, but for the wrong reasons.

Fixes: cf3e3e86d779 ("drm/i915: Use ttm mmap handling for ttm bo's.")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220106174910.280616-2-matthew.auld@intel.com

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 21277f3..f2af765 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -881,6 +881,11 @@ static vm_fault_t vm_fault_ttm(struct vm_fault *vmf)
        if (ret)
                return ret;
 
+       if (obj->mm.madv != I915_MADV_WILLNEED) {
+               dma_resv_unlock(bo->base.resv);
+               return VM_FAULT_SIGBUS;
+       }
+
        if (drm_dev_enter(dev, &idx)) {
                ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot,
                                               TTM_BO_VM_NUM_PREFAULT);