[src/trunk]: src/sys/external/bsd/drm2/dist/drm/i915/gem i915: Rearrange how ...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/0886e6977b6b
branches:  trunk
changeset: 1028905:0886e6977b6b
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Dec 19 12:26:55 2021 +0000

description:
i915: Rearrange how mmap offsets work.

Rather than use the magic offsets in each GEM object's uvm object
itself, just create a separate uvm object for each mapping type and
start at zero within each uvm object.  This should avoid problems
with things like ubc_uiomove which don't know to adjust the starting
offset.

diffstat:

 sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_mman.c         |  105 ++++-----
 sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_object_types.h |    6 +-
 2 files changed, 56 insertions(+), 55 deletions(-)

diffs (213 lines):

diff -r be692c388a2d -r 0886e6977b6b sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_mman.c
--- a/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_mman.c   Sun Dec 19 12:26:48 2021 +0000
+++ b/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_mman.c   Sun Dec 19 12:26:55 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: i915_gem_mman.c,v 1.20 2021/12/19 12:13:31 riastradh Exp $     */
+/*     $NetBSD: i915_gem_mman.c,v 1.21 2021/12/19 12:26:55 riastradh Exp $     */
 
 /*
  * SPDX-License-Identifier: MIT
@@ -7,7 +7,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: i915_gem_mman.c,v 1.20 2021/12/19 12:13:31 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: i915_gem_mman.c,v 1.21 2021/12/19 12:26:55 riastradh Exp $");
 
 #include <linux/anon_inodes.h>
 #include <linux/mman.h>
@@ -28,7 +28,9 @@
 #include "i915_user_extensions.h"
 #include "i915_vma.h"
 
-#ifndef __NetBSD__
+#ifdef __NetBSD__
+static const struct uvm_pagerops i915_mmo_gem_uvm_ops;
+#else
 static inline bool
 __vma_matches(struct vm_area_struct *vma, struct file *filp,
              unsigned long addr, unsigned long size)
@@ -338,8 +340,6 @@
        paddr_t paddr;
        int i;
 
-       startpage -= drm_vma_node_start(&mmo->vma_node);
-
        for (i = 0; i < npages; i++) {
                if ((flags & PGO_ALLPAGES) == 0 && i != centeridx)
                        continue;
@@ -411,7 +411,6 @@
 #ifdef __NetBSD__
        page_offset = (ufi->entry->offset + (vaddr - ufi->entry->start))
            >> PAGE_SHIFT;
-       page_offset -= drm_vma_node_start(&mmo->vma_node);
 #else
        /* We don't use vmf->pgoff since that has the fake offset */
        page_offset = (vmf->address - area->vm_start) >> PAGE_SHIFT;
@@ -546,14 +545,9 @@
     int npages, int centeridx, vm_prot_t access_type, int flags)
 {
        struct uvm_object *uobj = ufi->entry->object.uvm_obj;
-       voff_t uoffset;
-       unsigned long startpage;
-       struct drm_gem_object *gem =
-           container_of(uobj, struct drm_gem_object, gemo_uvmobj);
-       struct drm_i915_gem_object *obj = to_intel_bo(gem);
-       struct drm_device *dev = obj->base.dev;
-       struct drm_vma_offset_node *node;
-       struct i915_mmap_offset *mmo;
+       struct i915_mmap_offset *mmo =
+           container_of(uobj, struct i915_mmap_offset, uobj);
+       struct drm_i915_gem_object *obj = mmo->obj;
        bool pinned = false;
        int error;
 
@@ -574,44 +568,6 @@
         */
        rw_exit(obj->base.filp->vmobjlock);
 
-       KASSERT(ufi->entry->start <= vaddr);
-       KASSERT((ufi->entry->offset & (PAGE_SIZE - 1)) == 0);
-       uoffset = ufi->entry->offset + (vaddr - ufi->entry->start);
-       startpage = uoffset >> PAGE_SHIFT;
-
-       /*
-        * Look up the mmo again because we can't conveniently store it
-        * alongside the mapping unless we create a separate uvm object
-        * for it.  XXX Consider creating a separate uvm object as a
-        * kind of subobject of the main object.
-        *
-        * We use drm_vma_offset_lookup_locked because the number of
-        * pages we're faulting in here may be different from the
-        * number of pages that were mapped.
-        */
-       rcu_read_lock();
-       drm_vma_offset_lock_lookup(dev->vma_offset_manager);
-       node = drm_vma_offset_lookup_locked(dev->vma_offset_manager,
-           startpage, npages);
-       drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
-       rcu_read_unlock();
-
-       /*
-        * The mmo had better be there -- hope we can't remove the mmo
-        * without unmapping first!
-        */
-       KASSERT(node);
-       KASSERTMSG((ufi->entry->offset >> PAGE_SHIFT ==
-               drm_vma_node_start(node)),
-           /*
-            * Always provided by i915_gem_mmap_object, but in
-            * principle we could relax this.
-            */
-           "map startpage=%lx =/= node startpage=%lx",
-           ufi->entry->offset >> PAGE_SHIFT, drm_vma_node_start(node));
-       mmo = container_of(node, struct i915_mmap_offset, vma_node);
-       KASSERT(obj == mmo->obj);
-
        /* XXX errno Linux->NetBSD */
        error = -i915_gem_object_pin_pages(obj);
        if (error)
@@ -814,6 +770,7 @@
        if (to_free) {
                drm_vma_offset_remove(obj->base.dev->vma_offset_manager,
                    &to_free->vma_node);
+               uvm_obj_destroy(&to_free->uobj, /*free lock*/true);
                drm_vma_node_destroy(&to_free->vma_node);
                kfree(to_free);
        }
@@ -873,6 +830,9 @@
        mmo->mmap_type = mmap_type;
 #ifdef __NetBSD__
        drm_vma_node_init(&mmo->vma_node);
+       uvm_obj_init(&mmo->uobj, &i915_mmo_gem_uvm_ops, /*allocate lock*/false,
+           /*nrefs*/1);
+       uvm_obj_setlock(&mmo->uobj, obj->base.filp->vmobjlock);
 #else
        drm_vma_node_reset(&mmo->vma_node);
 #endif
@@ -902,6 +862,9 @@
        return mmo;
 
 err:
+#ifdef __NetBSD__
+       uvm_obj_destroy(&mmo->uobj, /*free lock*/true);
+#endif
        drm_vma_node_destroy(&mmo->vma_node);
        kfree(mmo);
        return ERR_PTR(err);
@@ -1036,9 +999,43 @@
 
 #ifdef __NetBSD__
 
+static int
+i915_gem_nofault(struct uvm_faultinfo *ufi, vaddr_t vaddr,
+    struct vm_page **pps, int npages, int centeridx, vm_prot_t access_type,
+    int flags)
+{
+       panic("i915 main gem object should not be mmapped directly");
+}
+
 const struct uvm_pagerops i915_gem_uvm_ops = {
        .pgo_reference = drm_gem_pager_reference,
        .pgo_detach = drm_gem_pager_detach,
+       .pgo_fault = i915_gem_nofault,
+};
+
+static void
+i915_mmo_reference(struct uvm_object *uobj)
+{
+       struct i915_mmap_offset *mmo =
+           container_of(uobj, struct i915_mmap_offset, uobj);
+       struct drm_i915_gem_object *obj = mmo->obj;
+
+       drm_gem_object_get(&obj->base);
+}
+
+static void
+i915_mmo_detach(struct uvm_object *uobj)
+{
+       struct i915_mmap_offset *mmo =
+           container_of(uobj, struct i915_mmap_offset, uobj);
+       struct drm_i915_gem_object *obj = mmo->obj;
+
+       drm_gem_object_put_unlocked(&obj->base);
+}
+
+static const struct uvm_pagerops i915_mmo_gem_uvm_ops = {
+       .pgo_reference = i915_mmo_reference,
+       .pgo_detach = i915_mmo_detach,
        .pgo_fault = i915_gem_fault,
 };
 
@@ -1082,8 +1079,8 @@
        }
 
        /* Success!  */
-       *uobjp = &obj->base.gemo_uvmobj;
-       *uoffsetp = (voff_t)startpage << PAGE_SHIFT;
+       *uobjp = &mmo->uobj;
+       *uoffsetp = 0;
        return 0;
 }
 
diff -r be692c388a2d -r 0886e6977b6b sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_object_types.h
--- a/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_object_types.h   Sun Dec 19 12:26:48 2021 +0000
+++ b/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_object_types.h   Sun Dec 19 12:26:55 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: i915_gem_object_types.h,v 1.6 2021/12/19 11:33:30 riastradh Exp $      */
+/*     $NetBSD: i915_gem_object_types.h,v 1.7 2021/12/19 12:26:55 riastradh Exp $      */
 
 /*
  * SPDX-License-Identifier: MIT
@@ -78,7 +78,11 @@
        struct drm_i915_gem_object *obj;
        enum i915_mmap_type mmap_type;
 
+#ifdef __NetBSD__
+       struct uvm_object uobj;
+#else
        struct rb_node offset;
+#endif
 };
 
 struct drm_i915_gem_object {