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>
