TTM takes full control over TTM_PL_SYSTEM placed buffers. This makes
driver internal usage of TTM_PL_SYSTEM prone to errors because it
requires the drivers to manually handle all interactions between TTM
which can swap out those buffers whenever it thinks it's the right
thing to do and driver.
CPU buffers which need to be fenced and shared with accelerators should
be placed in driver specific placements that can explicitly handle
CPU/accelerator buffer fencing.
Currently, apart, from things silently failing nothing is enforcing
that requirement which means that it's easy for drivers and new
developers to get this wrong. To avoid the confusion we can document
this requirement and clarify the solution.
This came up during a discussion on dri-devel:
https://lore.kernel.org/dri-devel/232f45e9-8748-1243-09bf-56763e6668b3@amd.com
Signed-off-by: Zack Rusin <zackr@vmware.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211110145034.487512-1-zackr@vmware.com
The huge page functionality in TTM does not work safely because PUD and
PMD entries do not have a special bit.
get_user_pages_fast() considers any page that passed pmd_huge() as
usable:
if (unlikely(pmd_trans_huge(pmd) || pmd_huge(pmd) ||
pmd_devmap(pmd))) {
And vmf_insert_pfn_pmd_prot() unconditionally sets
entry = pmd_mkhuge(pfn_t_pmd(pfn, prot));
eg on x86 the page will be _PAGE_PRESENT | PAGE_PSE.
As such gup_huge_pmd() will try to deref a struct page:
head = try_grab_compound_head(pmd_page(orig), refs, flags);
and thus crash.
Thomas further notices that the drivers are not expecting the struct page
to be used by anything - in particular the refcount incr above will cause
them to malfunction.
Thus everything about this is not able to fully work correctly considering
GUP_fast. Delete it entirely. It can return someday along with a proper
PMD/PUD_SPECIAL bit in the page table itself to gate GUP_fast.
Fixes: 314b6580ad ("drm/ttm, drm/vmwgfx: Support huge TTM pagefaults")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Thomas Hellström <thomas.helllstrom@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
[danvet: Update subject per Thomas' &Christian's review]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/0-v2-a44694790652+4ac-ttm_pmd_jgg@nvidia.com
UAPI Changes:
- Add uAPI for using PXP protected objects
Mesa changes: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8064
- Add PCI IDs and LMEM discovery/placement uAPI for DG1
Mesa changes: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11584
- Disable engine bonding on Gen12+ except TGL, RKL and ADL-S
Cross-subsystem Changes:
- Merges 'tip/locking/wwmutex' branch (core kernel tip)
- "mei: pxp: export pavp client to me client bus"
Core Changes:
- Update ttm_move_memcpy for async use (Thomas)
Driver Changes:
- Enable GuC submission by default on DG1 (Matt B)
- Add PXP (Protected Xe Path) support for Gen12 integrated (Daniele,
Sean, Anshuman)
See "drm/i915/pxp: add PXP documentation" for details!
- Remove force_probe protection for ADL-S (Raviteja)
- Add base support for XeHP/XeHP SDV (Matt R, Stuart, Lucas)
- Handle DRI_PRIME=1 on Intel igfx + Intel dgfx hybrid graphics setup (Tvrtko)
- Use Transparent Hugepages when IOMMU is enabled (Tvrtko, Chris)
- Implement LMEM backup and restore for suspend / resume (Thomas)
- Report INSTDONE_GEOM values in error state for DG2 (Matt R)
- Add DG2-specific shadow register table (Matt R)
- Update Gen11/Gen12/XeHP shadow register tables (Matt R)
- Maintain backward-compatible nested batch behavior on TGL+ (Matt R)
- Add new LRI reg offsets for DG2 (Akeem)
- Initialize unused MOCS entries to device specific values (Ayaz)
- Track and use the correct UC MOCS index on Gen12 (Ayaz)
- Add separate MOCS table for Gen12 devices other than TGL/RKL (Ayaz)
- Simplify the locking and eliminate some RCU usage (Daniel)
- Add some flushing for the 64K GTT path (Matt A)
- Mark GPU wedging on driver unregister unrecoverable (Janusz)
- Major rework in the GuC codebase, simplify locking and add docs (Matt B)
- Add DG1 GuC/HuC firmwares (Daniele, Matt B)
- Remember to call i915_sw_fence_fini on guc_state.blocked (Matt A)
- Use "gt" forcewake domain name for error messages instead of "blitter" (Matt R)
- Drop now duplicate LMEM uAPI RFC kerneldoc section (Daniel)
- Fix early tracepoints for requests (Matt A)
- Use locked access to ctx->engines in set_priority (Daniel)
- Convert gen6/gen7/gen8 read operations to fwtable (Matt R)
- Drop gen11/gen12 specific mmio write handlers (Matt R)
- Drop gen11 specific mmio read handlers (Matt R)
- Use designated initializers for init/exit table (Kees)
- Fix syncmap memory leak (Matt B)
- Add pretty printing for buddy allocator state debug (Matt A)
- Fix potential error pointer dereference in pinned_context() (Dan)
- Remove IS_ACTIVE macro (Lucas)
- Static code checker fixes (Nathan)
- Clean up disabled warnings (Nathan)
- Increase timeout in i915_gem_contexts selftests 5x for GuC submission (Matt B)
- Ensure wa_init_finish() is called for ctx workaround list (Matt R)
- Initialize L3CC table in mocs init (Sreedhar, Ayaz, Ram)
- Get PM ref before accessing HW register (Vinay)
- Move __i915_gem_free_object to ttm_bo_destroy (Maarten)
- Deduplicate frequency dump on debugfs (Lucas)
- Make wa list per-gt (Venkata)
- Do not define dummy vma in stack (Venkata)
- Take pinning into account in __i915_gem_object_is_lmem (Matt B, Thomas)
- Do not report currently active engine when describing objects (Tvrtko)
- Fix pdfdocs build error by removing nested grid from GuC docs (Akira)
- Remove false warning from the rps worker (Tejas)
- Flush buffer pools on driver remove (Janusz)
- Fix runtime pm handling in i915_gem_shrink (Maarten)
- Rework TTM object initialization slightly (Thomas)
- Use fixed offset for PTEs location (Michal Wa)
- Verify result from CTB (de)register action and improve error messages (Michal Wa)
- Fix bug in user proto-context creation that leaked contexts (Matt B)
- Re-use Gen11 forcewake read functions on Gen12 (Matt R)
- Make shadow tables range-based (Matt R)
- Ditch the i915_gem_ww_ctx loop member (Thomas, Maarten)
- Use NULL instead of 0 where appropriate (Ville)
- Rename pci/debugfs functions to respect file prefix (Jani, Lucas)
- Drop guc_communication_enabled (Daniele)
- Selftest fixes (Thomas, Daniel, Matt A, Maarten)
- Clean up inconsistent indenting (Colin)
- Use direction definition DMA_BIDIRECTIONAL instead of
PCI_DMA_BIDIRECTIONAL (Cai)
- Add "intel_" as prefix in set_mocs_index() (Ayaz)
From: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/YWAO80MB2eyToYoy@jlahtine-mobl.ger.corp.intel.com
Signed-off-by: Dave Airlie <airlied@redhat.com>
In commit:
commit 667a50db04
Author: Thomas Hellstrom <thellstrom@vmware.com>
Date: Fri Jan 3 11:17:18 2014 +0100
drm/ttm: Refuse to fault (prime-) imported pages
we introduced the restriction that imported pages should not be directly
mappable through TTM(this also extends to userptr). In the next patch we
want to introduce a shmem_tt backend, which should follow all the
existing rules with TTM_PAGE_FLAG_EXTERNAL, since it will need to handle
swapping itself, but with the above mapping restriction lifted.
v2(Christian):
- Don't OR together EXTERNAL and EXTERNAL_MAPPABLE in the definition
of EXTERNAL_MAPPABLE, just leave it the caller to handle this
correctly, otherwise we might encounter subtle issues.
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210929132629.353541-3-matthew.auld@intel.com
Signed-off-by: Christian König <christian.koenig@amd.com>
Close the divergence which has caused patches not to apply and
have a solid baseline for the PXP patches that Rodrigo will send
a topic branch PR for.
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
The internal ttm_bo_util memcpy uses ioremap functionality, and while it
probably might be possible to use it for copying in- and out of
sglist represented io memory, using io_mem_reserve() / io_mem_free()
callbacks, that would cause problems with fault().
Instead, implement a method mapping page-by-page using kmap_local()
semantics. As an additional benefit we then avoid the occasional global
TLB flushes of ioremap() and consuming ioremap space, elimination of a
critical point of failure and with a slight change of semantics we could
also push the memcpy out async for testing and async driver development
purposes.
A special linear iomem iterator is introduced internally to mimic the
old ioremap behaviour for code-paths that can't immediately be ported
over. This adds to the code size and should be considered a temporary
solution.
Looking at the code we have a lot of checks for iomap tagged pointers.
Ideally we should extend the core memremap functions to also accept
uncached memory and kmap_local functionality. Then we could strip a
lot of code.
Cc: Christian König <christian.koenig@amd.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20210602083818.241793-4-thomas.hellstrom@linux.intel.com
On device removal reroute all CPU mappings to dummy page.
v3:
Remove loop to find DRM file and instead access it
by vma->vm_file->private_data. Move dummy page installation
into a separate function.
v4:
Map the entire BOs VA space into on demand allocated dummy page
on the first fault for that BO.
v5: Remove duplicate return.
v6: Polish ttm_bo_vm_dummy_page, remove superfluous code.
Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210512142648.666476-2-andrey.grodzovsky@amd.com
msm-next pull request has a baseline with stuff from -fixes, roll
forward first.
Some simple conflicts in amdgpu, ttm and one in i915 where git gets
confused and tries to add the same function twice.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
TTM implements a rather extensive accounting of allocated memory.
There are two reasons for this:
1. It tries to block userspace allocating a huge number of very small
BOs without accounting for the kmalloced memory.
2. Make sure we don't over allocate and run into an OOM situation
during swapout while trying to handle the memory shortage.
This is only partially a good idea. First of all it is perfectly
valid for an application to use all of system memory, limiting it to
50% is not really acceptable.
What we need to take care of is that the application is held
accountable for the memory it allocated. This is what control
mechanisms like memcg and the normal Linux page accounting already do.
Making sure that we don't run into an OOM situation while trying to
cope with a memory shortage is still a good idea, but this is also
not very well implemented since it means another opportunity of
recursion from the driver back into TTM.
So start to rework all of this by implementing a shrinker callback which
allows for TT object to be swapped out if necessary.
v2: Switch from limit to shrinker callback.
v3: fix gfp mask handling, use atomic for swapable_pages, add debugfs
v4: drop the extra gfp_mask checks
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210208133226.36955-1-christian.koenig@amd.com
ttm_resource_manager->use_type is only used for runtime changes by
vmwgfx. I think ideally we'd push this functionality into drivers -
ttm itself does not provide any locking to guarantee this is safe, so
the only way this can work at runtime is if the driver does provide
additional guarantees. vwmgfx does that through the
vmw_private->reservation_sem. Therefore supporting this feature in
shared code feels a bit misplaced.
As a first step add a WARN_ON to make sure the resource manager is
empty. This is just to make sure I actually understand correctly what
vmwgfx is doing, and to make sure an eventual subsequent refactor
doesn't break anything.
This check should also be useful for other drivers, to make sure they
haven't leaked anything.
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Huang Rui <ray.huang@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201211162942.3399050-3-daniel.vetter@ffwll.ch
