The FBC hardware for these platforms doesn't have access to the
bios_reserved range, so it always assumes the maximum (8mb) is used.
So avoid this range while allocating.

This solves a bunch of FIFO underruns that happen if you end up
putting the CFB in that memory range. On my machine, with 32mb of
stolen, I need a 2560x1440 mode for that.

Testcase: igt/kms_frontbuffer_tracking/fbc-* (given the right setup)
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This stolen reserved stuff was introduced on g4x, so no need to waste
stolen on older platforms. Unfortunately configdb is no more so I can't
look up the right way to detect this stuff. I do have one hint as to
where the register might be on ctg, but I don't have a ctg to test it,
and on the elk I have here it doesn't contain sensible looking data.
For ilk grits suggegsts it might be in the same place as on snb (the
original PCI reg, not the mirror) but I can't be entirely sure about it
The register shows a round zero on my ilk.

So when there's no really good data for any of these platforms leave the
current "assume 1MiB" approach in place.

Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The gtt.stolen_size field is of type size_t, and so should be printed
using %zu to avoid build warnings on either 32-bit and 64-bit builds.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

I started digging this when I noticed that the BDW code was just
reserving 1mb by coincidence since it was reading reserved fields.
Then I noticed we didn't have any values set for SNB and earlier, and
that the HSW sizes were wrong. After that, I noticed that the reserved
area has a specific start, and may not exactly end where the stolen
memory ends. I also noticed the base pointer can be zero. So I decided
to just write a single patch fixing everything instead of 20 patches
that would be much harder to review.

This patch may solve random stolen memory corruption/problems on
almost all platforms. Notice that since this is always dealing with
the top of the stolen memory, the problems are not so easy to
reproduce - especially since FBC is still disabled by default.

One of the major differences of this patch is that we now look at both
the size and base address. By only looking at the size we were
assuming that the reserved area was always at the very top of
stolen, which is not always true.

After we merge the patch series that allows user space to allocate
stolen memory we'll be able to write IGT tests that maybe catch the
bugs fixed by this patch.

v2:
  - s/BIOS reserved/stolen reserved/g (Chris)
  - Don't DRM_ERROR if we can't do anything about it (Chris)
  - Improve debug messages (Chris).
  - Use the gen7 version instead of gen6 on HSW. Tom found some
    documentation problems, so I think with gen7 we're on the safer
    side (Tom).
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

After the previous patch this flag will check always clear, as it's
never set for shmem backed and userptr objects, so we can remove it.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
[danvet: Yeah this isn't really fixes but it's a nice cleanup to
clarify the code but not really worth the hassle of backmerging. So
just add to -fixes, we're still early in -rc.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Which should protect dev_priv->mm.stolen usage. This will allow us to
simplify the relationship between stolen memory, FBC and struct_mutex.

v2:
  - Rebase after the stolen_remove_node() dev_priv patch move.
  - I realized that after we fixed a few things related to the FBC CFB
    size checks, we're not reallocating the CFB anymore with FBC
    enabled, so we can just move all the locking to i915_gem_stolen.c
    and stop worrying about freezing all the stolen alocations while
    freeing/rellocating the CFB. This allows us to fix the "Too
    coarse" observation from Chris.
Suggested-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

With the abstractions created by the last patch, we can move this code
and the only thing inside intel_fbc.c that knows about dev_priv->mm is
the code that reads stolen_base.

We also had to move a call to i915_gem_stolen_cleanup_compression()
- now called intel_fbc_cleanup_cfb() - outside i915_gem_stolen.c.

v2:
  - Rebase after the remove_node() changes on the previous patch.
Requested-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We want to move the FBC code out of i915_gem_stolen.c, but that code
directly adds/removes stolen memory nodes. Let's create this
abstraction, so i915_gme_stolen.c is still in control of all the
stolen memory handling. The abstraction will also allow us to add
locking assertions later.

v2:
  - Add dev_priv as remove_node() argument since we'll need it later
    (Chris).
Requested-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Starting from GEN5 the FBC base register is the same on all platforms.
GEN>=5 is the same condition as HAS_PCH_SPLIT except on BXT, so make
things work on BXT as well.

Motivated by Rodrigo's request to check FBC support on BXT.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NAntti Koskipää <antti.koskipaa@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Some bios really like to joke and start the planes at an offset ...
hooray!

Align start and end to fix this.

v2: Fixup calculation of size, spotted by Chris Wilson.

v3: Fix serious fumble I've just spotted.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=86883
Cc: stable@vger.kernel.org
Cc: Johannes W <jargon@molb.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Reported-and-tested-by: NJohannes W <jargon@molb.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
[Jani: split WARN_ONs, rebase on v4.0-rc1]
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

With the current code we just reallocate the compressed FB at every
FBC update: we have X in one frame, then in the other frame we need X
again, but we check "needed < have" instead of "needed <= have".

v2: Rebase after Jani addressed the other problems described in v1.

Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The check for previously reserved stolen space size for FBC in
i915_gem_stolen_setup_compression() did not take the compression
threshold into account. Fix this by storing and comparing to
uncompressed size instead.

The bug has been introduced in

commit 5e59f717
Author: Ben Widawsky <benjamin.widawsky@intel.com>
Date:   Mon Jun 30 10:41:24 2014 -0700

    drm/i915: Try harder to get FBC

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88975Suggested-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Apparently stuff works that way on those machines.

I agree with Chris' concern that this is a bit risky but imo worth a
shot in -next just for fun. Afaics all these machines have the pci
resources allocated like that by the BIOS, so I suspect that it's all
ok.

This regression goes back to

commit eaba1b8f
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Thu Jul 4 12:28:35 2013 +0100

    drm/i915: Verify that our stolen memory doesn't conflict

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76983
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=71031Tested-by: Nlu hua <huax.lu@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: NPaul Menzel <paulepanter@users.sourceforge.net>
Cc: stable@vger.kernel.org
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

If these flags are on the object level it will be more difficult to allow
for multiple VMAs per object.

v2: Simplification and cleanup after code review comments (Chris Wilson).
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Based upon a patch from Deepak, but reworked to only apply on gen7+
and with the logic a bit clarified.

v2: Fix s/SHIFT/MASK/ fumble that Ville spotted.

Cc: Deepak S <deepak.s@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On most gen2-4 platforms the GTT can be (or maybe always is?)
inside the stolen memory region. If that's the case, reduce the
size of the stolen memory appropriately to make make sure we
don't clobber the GTT.

v2: Deal with gen4 36 bit physical address
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80151Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The GEN FBC unit provides the ability to set a low pass on frames it
attempts to compress. If a frame is less than a certain amount
compressibility (2:1, 4:1) it will not bother. This allows the driver to
reduce the size it requests out of stolen memory.

Unluckily, a few months ago, Ville actually began using this feature for
framebuffers that are 16bpp (not sure why not 8bpp). In those cases, we
are already using this mechanism for a different purpose, and so we can
only achieve one further level of compression (2:1 -> 4:1)

FBC GEN1, ie. pre-G45 is ignored.

The cleverness of the patch is Art's. The bugs are mine.

v2: Update message and including missing threshold case 3 (Spotted by Arthur).

Cc: Art Runyan <arthur.j.runyan@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Right now, there is no threshold (0 means fail, 1 means 1:1 compression
limit). This is to split the function/non-functional change of the next
patch.

The next patch will start to attempt to reduce the amount of CFB space
we need for dire situations. It will be contained within this function.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

We are already using the size to determine whether or not to free the
object, so there is no functional change there. Almost everything else
has changed to static allocations of the drm_mm_node too.

Aside from bringing this inline with much of our other code, this makes
error paths slightly simpler, which benefits the look of an upcoming
patch.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Now that we have a release hook into i915_gem_object_free, we can move
the explicit call to the internal stolen function and hook it up
throught the callback instead.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We want future generations to at least attempt to use all features, so
restrict the stolen memory disabling when vt-d is enabled to the
latest generation we have reports for. Which is a HSW per the original
report.

Also once we get a bit a hold of some of the mysterious framebuffer in
stolen memory issues that still haunt bugzilla, we should probably
drop this hack again and see what happens.

This was introduced in

commit 0f4706d2
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Tue Mar 18 14:50:50 2014 +0200

    drm/i915: Disable stolen memory when DMAR is active

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
References: https://bugs.freedesktop.org/show_bug.cgi?id=68535Acked-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We have reports of heavy screen corruption if we try to use the stolen
memory reserved by the BIOS whilst the DMA-Remapper is active. This
quirk may be only specific to a few machines or BIOSes, but first lets
apply the big hammer and always disable use of stolen memory when DMAR
is active.

v2 by Jani: Rebase on -fixes, only look at intel_iommu_gfx_mapped.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=68535Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

There is a conflict seen when requesting the kernel to reserve
the physical space used for the stolen area. This is because
some BIOS are wrapping the stolen area in the root PCI bus, but have
an off-by-one error. As a workaround we retry the reservation with an
offset of 1 instead of 0.

v2: updated commit message & the comment in source file (Daniel)
Signed-off-by: NAkash Goel <akash.goel@intel.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

The 'offset' field of the 'scatterlist' structure was wrongly
programmed with the offset value from the base of stolen area,
whereas this field indicates the offset from where the interested
data starts within the first PAGE pointed to by 'scattterlist'
structure. As a result when a new GEM object allocated from stolen
area is mapped to GTT, it could lead to an overwrite of GTT entries
as the page count calculation will go wrong, refer the function
'sg_page_count'.

v2: Modified the commit message. (Chris)
Signed-off-by: NAkash Goel <akash.goel@intel.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Cc: stable@vger.kernel.org
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=71908
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=69104Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

But only when we indeed set up a gtt mapping. We need this since the
vma also holds a pages_pin_count, on top of the unconditional
pages_pin_count we grab for all stolen objects (to avoid swap-out).

This should avoid a pages_pin_count underrun when cleaning up
framebuffers objects taken over from the BIOS.

Chris mentioned in his review that this bug even predates the vma
conversion.
Reported-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Paulo reported that if he set the amount of reserved memory to 0, then
we emitted a warning about a conflict before disabling our use of stolen
memory. This was introduced with

commit eaba1b8f
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Thu Jul 4 12:28:35 2013 +0100

    drm/i915: Verify that our stolen memory doesn't conflict

and is simply fixed by checking for a no reservation first.
Reported-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In the execbuf code we don't clean up any vmas which ended up not
getting bound for code simplicity. To make sure that we don't end up
creating multiple vma for the same vm kill the somewhat dangerous
vma_create function and inline it into lookup_or_create.

This is just a safety measure to prevent surprises in the future.

Also update the somewhat confused comment in the execbuf code and
clarify what kind of magic is going on with a new one.

v2: Keep the function separate as requested by Chris. But give it a __
prefix for paranoia and move it tighter together with the other vma
stuff.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Widawsky <ben@bwidawsk.net>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Use the standard inversely ordered goto label stack for everything.
Spotted while reviewing place where we might need to to call
vma_destroy but failed to do so.

Cc: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

As a corollary to reviewing the interaction between LLC and our cache
domains, the GPU PTE bits are independent of the CPU PAT bits. As such
we can set the cache level on stolen memory based on how we wish the GPU
to cache accesses to it. So we are free to set the same default cache
levels as for normal bo, i.e. enable LLC cacheing by default where
appropriate.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

formerly: "drm/i915: Create VMAs (part 5) - move mm_list"

The mm_list is used for the active/inactive LRUs. Since those LRUs are
per address space, the link should be per VMx .

Because we'll only ever have 1 VMA before this point, it's not incorrect
to defer this change until this point in the patch series, and doing it
here makes the change much easier to understand.

Shamelessly manipulated out of Daniel:
"active/inactive stuff is used by eviction when we run out of address
space, so needs to be per-vma and per-address space. Bound/unbound otoh
is used by the shrinker which only cares about the amount of memory used
and not one bit about in which address space this memory is all used in.
Of course to actual kick out an object we need to unbind it from every
address space, but for that we have the per-object list of vmas."

v2: only bump GGTT LRU in i915_gem_object_set_to_gtt_domain (Chris)

v3: Moved earlier in the series

v4: Add dropped message from v3
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
[danvet: Frob patch to apply and use vma->node.size directly as
discused with Ben. Also drop a needles BUG_ON before move_to_inactive,
the function itself has the same check.]
[danvet 2nd: Rebase on top of the lost "drm/i915: Cleanup more of VMA
in destroy", specifically unlink the vma from the mm_list in
vma_unbind (to keep it symmetric with bind_to_vm) instead of
vma_destroy.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

i915 is the last user of the weird search+get_block drm_mm API. Convert it
to an explicit kmalloc()+insert_node(). This drops the last user of the
node-cache in drm_mm. We can remove it now in a follow-up patch.

v2:
 - simplify error path in i915_setup_compression()
v3:
 - simplify error path even more

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Add a "best_match" flag similar to the drm_mm_search_*() helpers so we
can convert TTM to use them in follow up patches. We can also inline the
non-generic helpers and move them into the header to allow compile-time
optimizations.

To make calls to drm_mm_{search,insert}_node() more readable, this
converts the boolean argument to a flagset. There are pending patches that
add additional flags for top-down allocators and more.

v2:
 - use flag parameter instead of boolean "best_match"
 - convert *_search_free() helpers to also use flags argument
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Just some small cleanups, and a rename of vm->ggtt_vm requested by
Daniel.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

So I made the mistake of missing that the desktop and mobile chipsets
have different layouts in their PCI configurations, and we were
incorrectly setting the wrong physical address for stolen memory on
mobile chipsets.

Since all gen3+ are actually consistent in the location of the GBSM
register in the PCI configuration space on device 2 (the GPU), use it.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
[danvet: Drop cc: stable and fudge conflicts.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drm_gem_object_init() and drm_gem_private_object_init() do exactly the
same (except for shmem alloc) so make the first use the latter to reduce
code duplication.

Also drop the return code from drm_gem_private_object_init(). It seems
unlikely that we will extend it any time soon so no reason to keep it
around. This simplifies code paths in drivers, too.

Last but not least, fix gma500 to call drm_gem_object_release() before
freeing objects that were allocated via drm_gem_private_object_init().
That isn't actually necessary for now, but might be in the future.
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NPatrik Jakobsson <patrik.r.jakobsson@gmail.com>
Acked-by: NRob Clark <robdclark@gmail.com>
Signed-off-by: NDave Airlie <airlied@gmail.com>

i915_gem_vma_create() returns and ERR_PTR() or a valid pointer, it never
returns NULL.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Formerly: "drm/i915: Create VMAs (part 1)"

In a previous patch, the notion of a VM was introduced. A VMA describes
an area of part of the VM address space. A VMA is similar to the concept
in the linux mm. However, instead of representing regular memory, a VMA
is backed by a GEM BO. There may be many VMAs for a given object, one
for each VM the object is to be used in. This may occur through flink,
dma-buf, or a number of other transient states.

Currently the code depends on only 1 VMA per object, for the global GTT
(and aliasing PPGTT). The following patches will address this and make
the rest of the infrastructure more suited

v2: s/i915_obj/i915_gem_obj (Chris)

v3: Only move an object to the now global unbound list if there are no
more VMAs for the object which are bound into a VM (ie. the list is
empty).

v4: killed obj->gtt_space
some reworks due to rebase

v5: Free vma on error path (Imre)

v6: Another missed vma free in i915_gem_object_bind_to_gtt error path
(Imre)
Fixed vma freeing in stolen preallocation (Imre)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NImre Deak <imre.deak@intel.com>
[danvet: Squash in fixup from Ben to not deref a non-existing vma in
set_cache_level, reported by Chris.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The odds of this happening are *extremely* unlikely.
Reported-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Shamelessly manipulated out of Daniel :-)
"When moving the lists around explain that the active/inactive stuff is
used by eviction when we run out of address space, so needs to be
per-vma and per-address space. Bound/unbound otoh is used by the
shrinker which only cares about the amount of memory used and not one
bit about in which address space this memory is all used in. Of course
to actual kick out an object we need to unbind it from every address
space, but for that we have the per-object list of vmas."

v2: Leave the bound list as a global one. (Chris, indirectly)

v3: Rebased with no i915_gtt_vm. In most places I added a new *vm local,
since it will eventually be replaces by a vm argument.
Put comment back inline, since it no longer makes sense to do otherwise.

v4: Rebased on hangcheck/error state movement
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Every address space should support object allocation. It therefore makes
sense to have the allocator be part of the "superclass" which GGTT and
PPGTT will derive.

Since our maximum address space size is only 2GB we're not yet able to
avoid doing allocation/eviction; but we'd hope one day this becomes
almost irrelvant.

v2: Rebased
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>