kernel.git/drivers/gpu/drm/i915/gem, branch linux-5.3.y

drm/i915/userptr: Try to acquire the page lock around set_page_dirty()

2019-11-29T09:07:51Z

commit 2d691aeca4aecbb8d0414a777a46981a8e142b05 upstream. set_page_dirty says: For pages with a mapping this should be done under the page lock for the benefit of asynchronous memory errors who prefer a consistent dirty state. This rule can be broken in some special cases, but should be better not to. Under those rules, it is only safe for us to use the plain set_page_dirty calls for shmemfs/anonymous memory. Userptr may be used with real mappings and so needs to use the locked version (set_page_dirty_lock). However, following a try_to_unmap() we may want to remove the userptr and so call put_pages(). However, try_to_unmap() acquires the page lock and so we must avoid recursively locking the pages ourselves -- which means that we cannot safely acquire the lock around set_page_dirty(). Since we can't be sure of the lock, we have to risk skip dirtying the page, or else risk calling set_page_dirty() without a lock and so risk fs corruption. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203317 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=112012 Fixes: 5cc9ed4b9a7a ("drm/i915: Introduce mapping of user pages into video memory (userptr) ioctl") References: cb6d7c7dc7ff ("drm/i915/userptr: Acquire the page lock around set_page_dirty()") References: 505a8ec7e11a ("Revert "drm/i915/userptr: Acquire the page lock around set_page_dirty()"") References: 6dcc693bc57f ("ext4: warn when page is dirtied without buffers") Signed-off-by: Chris Wilson Cc: Lionel Landwerlin Cc: Tvrtko Ursulin Cc: Joonas Lahtinen Cc: stable@vger.kernel.org Reviewed-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20191111133205.11590-1-chris@chris-wilson.co.uk (cherry picked from commit 0d4bbe3d407f79438dc4f87943db21f7134cfc65) Signed-off-by: Joonas Lahtinen (cherry picked from commit cee7fb437edcdb2f9f8affa959e274997f5dca4d) Signed-off-by: Rodrigo Vivi Signed-off-by: Greg Kroah-Hartman

drm/i915/cmdparser: Add support for backward jumps

2019-11-12T18:28:25Z

commit f8c08d8faee5567803c8c533865296ca30286bbf upstream. To keep things manageable, the pre-gen9 cmdparser does not attempt to track any form of nested BB_START's. This did not prevent usermode from using nested starts, or even chained batches because the cmdparser is not strictly enforced pre gen9. Instead, the existence of a nested BB_START would cause the batch to be emitted in insecure mode, and any privileged capabilities would not be available. For Gen9, the cmdparser becomes mandatory (for BCS at least), and so not providing any form of nested BB_START support becomes overly restrictive. Any such batch will simply not run. We make heavy use of backward jumps in igt, and it is much easier to add support for this restricted subset of nested jumps, than to rewrite the whole of our test suite to avoid them. Add the required logic to support limited backward jumps, to instructions that have already been validated by the parser. Note that it's not sufficient to simply approve any BB_START that jumps backwards in the buffer because this would allow an attacker to embed a rogue instruction sequence within the operand words of a harmless instruction (say LRI) and jump to that. We introduce a bit array to track every instr offset successfully validated, and test the target of BB_START against this. If the target offset hits, it is re-written to the same offset in the shadow buffer and the BB_START cmd is allowed. Note: This patch deliberately ignores checkpatch issues in the cmdtables, in order to match the style of the surrounding code. We'll correct the entire file in one go in a later patch. v2: set dispatch secure late (Mika) v3: rebase (Mika) v4: Clear whitelist on each parse Minor review updates (Chris) v5: Correct backward jump batching v6: fix compilation error due to struct eb shuffle (Mika) Cc: Tony Luck Cc: Dave Airlie Cc: Takashi Iwai Cc: Tyler Hicks Signed-off-by: Jon Bloomfield Signed-off-by: Mika Kuoppala Reviewed-by: Chris Wilson Signed-off-by: Greg Kroah-Hartman

drm/i915: Allow parsing of unsized batches

2019-11-12T18:28:24Z

commit 435e8fc059dbe0eec823a75c22da2972390ba9e0 upstream. In "drm/i915: Add support for mandatory cmdparsing" we introduced the concept of mandatory parsing. This allows the cmdparser to be invoked even when user passes batch_len=0 to the execbuf ioctl's. However, the cmdparser needs to know the extents of the buffer being scanned. Refactor the code to ensure the cmdparser uses the actual object size, instead of the incoming length, if user passes 0. Signed-off-by: Jon Bloomfield Cc: Tony Luck Cc: Dave Airlie Cc: Takashi Iwai Cc: Tyler Hicks Reviewed-by: Chris Wilson Signed-off-by: Greg Kroah-Hartman

drm/i915: Support ro ppgtt mapped cmdparser shadow buffers

2019-11-12T18:28:24Z

commit 4f7af1948abcb18b4772fe1bcd84d7d27d96258c upstream. For Gen7, the original cmdparser motive was to permit limited use of register read/write instructions in unprivileged BB's. This worked by copying the user supplied bb to a kmd owned bb, and running it in secure mode, from the ggtt, only if the scanner finds no unsafe commands or registers. For Gen8+ we can't use this same technique because running bb's from the ggtt also disables access to ppgtt space. But we also do not actually require 'secure' execution since we are only trying to reduce the available command/register set. Instead we will copy the user buffer to a kmd owned read-only bb in ppgtt, and run in the usual non-secure mode. Note that ro pages are only supported by ppgtt (not ggtt), but luckily that's exactly what we need. Add the required paths to map the shadow buffer to ppgtt ro for Gen8+ v2: IS_GEN7/IS_GEN (Mika) v3: rebase v4: rebase v5: rebase Signed-off-by: Jon Bloomfield Cc: Tony Luck Cc: Dave Airlie Cc: Takashi Iwai Cc: Tyler Hicks Signed-off-by: Mika Kuoppala Reviewed-by: Chris Wilson Signed-off-by: Greg Kroah-Hartman

drm/i915: Add support for mandatory cmdparsing

2019-11-12T18:28:23Z

commit 311a50e76a33d1e029563c24b2ff6db0c02b5afe upstream. The existing cmdparser for gen7 can be bypassed by specifying batch_len=0 in the execbuf call. This is safe because bypassing simply reduces the cmd-set available. In a later patch we will introduce cmdparsing for gen9, as a security measure, which must be strictly enforced since without it we are vulnerable to DoS attacks. Introduce the concept of 'required' cmd parsing that cannot be bypassed by submitting zero-length bb's. v2: rebase (Mika) v2: rebase (Mika) v3: fix conflict on engine flags (Mika) Signed-off-by: Jon Bloomfield Cc: Tony Luck Cc: Dave Airlie Cc: Takashi Iwai Cc: Tyler Hicks Signed-off-by: Mika Kuoppala Reviewed-by: Chris Wilson Signed-off-by: Greg Kroah-Hartman

drm/i915: Remove Master tables from cmdparser

2019-11-12T18:28:23Z

commit 66d8aba1cd6db34af10de465c0d52af679288cb6 upstream. The previous patch has killed support for secure batches on gen6+, and hence the cmdparsers master tables are now dead code. Remove them. Signed-off-by: Jon Bloomfield Cc: Tony Luck Cc: Dave Airlie Cc: Takashi Iwai Cc: Tyler Hicks Reviewed-by: Chris Wilson Signed-off-by: Greg Kroah-Hartman

drm/i915: Disable Secure Batches for gen6+

2019-11-12T18:28:23Z

commit 44157641d448cbc0c4b73c5231d2b911f0cb0427 upstream. Retroactively stop reporting support for secure batches through the api for gen6+ so that older binaries trigger the fallback path instead. Older binaries use secure batches pre gen6 to access resources that are not available to normal usermode processes. However, all known userspace explicitly checks for HAS_SECURE_BATCHES before relying on the secure batch feature. Since there are no known binaries relying on this for newer gens we can kill secure batches from gen6, via I915_PARAM_HAS_SECURE_BATCHES. v2: rebase (Mika) v3: rebase (Mika) Signed-off-by: Jon Bloomfield Cc: Tony Luck Cc: Dave Airlie Cc: Takashi Iwai Cc: Tyler Hicks Signed-off-by: Mika Kuoppala Reviewed-by: Chris Wilson Signed-off-by: Greg Kroah-Hartman

drm/i915/userptr: Never allow userptr into the mappable GGTT

2019-10-29T08:22:25Z

commit 4f2a572eda67aecb1e7e4fc26cc985fb8158f6e8 upstream. Daniel Vetter uncovered a nasty cycle in using the mmu-notifiers to invalidate userptr objects which also happen to be pulled into GGTT mmaps. That is when we unbind the userptr object (on mmu invalidation), we revoke all CPU mmaps, which may then recurse into mmu invalidation. We looked for ways of breaking the cycle, but the revocation on invalidation is required and cannot be avoided. The only solution we could see was to not allow such GGTT bindings of userptr objects in the first place. In practice, no one really wants to use a GGTT mmapping of a CPU pointer... Just before Daniel's explosive lockdep patches land in v5.4-rc1, we got a genuine blip from CI: <4>[ 246.793958] ====================================================== <4>[ 246.793972] WARNING: possible circular locking dependency detected <4>[ 246.793989] 5.3.0-gbd6c56f50d15-drmtip_372+ #1 Tainted: G U <4>[ 246.794003] ------------------------------------------------------ <4>[ 246.794017] kswapd0/145 is trying to acquire lock: <4>[ 246.794030] 000000003f565be6 (&dev->struct_mutex/1){+.+.}, at: userptr_mn_invalidate_range_start+0x18f/0x220 [i915] <4>[ 246.794250] but task is already holding lock: <4>[ 246.794263] 000000001799cef9 (&anon_vma->rwsem){++++}, at: page_lock_anon_vma_read+0xe6/0x2a0 <4>[ 246.794291] which lock already depends on the new lock. <4>[ 246.794307] the existing dependency chain (in reverse order) is: <4>[ 246.794322] -> #3 (&anon_vma->rwsem){++++}: <4>[ 246.794344] down_write+0x33/0x70 <4>[ 246.794357] __vma_adjust+0x3d9/0x7b0 <4>[ 246.794370] __split_vma+0x16a/0x180 <4>[ 246.794385] mprotect_fixup+0x2a5/0x320 <4>[ 246.794399] do_mprotect_pkey+0x208/0x2e0 <4>[ 246.794413] __x64_sys_mprotect+0x16/0x20 <4>[ 246.794429] do_syscall_64+0x55/0x1c0 <4>[ 246.794443] entry_SYSCALL_64_after_hwframe+0x49/0xbe <4>[ 246.794456] -> #2 (&mapping->i_mmap_rwsem){++++}: <4>[ 246.794478] down_write+0x33/0x70 <4>[ 246.794493] unmap_mapping_pages+0x48/0x130 <4>[ 246.794519] i915_vma_revoke_mmap+0x81/0x1b0 [i915] <4>[ 246.794519] i915_vma_unbind+0x11d/0x4a0 [i915] <4>[ 246.794519] i915_vma_destroy+0x31/0x300 [i915] <4>[ 246.794519] __i915_gem_free_objects+0xb8/0x4b0 [i915] <4>[ 246.794519] drm_file_free.part.0+0x1e6/0x290 <4>[ 246.794519] drm_release+0xa6/0xe0 <4>[ 246.794519] __fput+0xc2/0x250 <4>[ 246.794519] task_work_run+0x82/0xb0 <4>[ 246.794519] do_exit+0x35b/0xdb0 <4>[ 246.794519] do_group_exit+0x34/0xb0 <4>[ 246.794519] __x64_sys_exit_group+0xf/0x10 <4>[ 246.794519] do_syscall_64+0x55/0x1c0 <4>[ 246.794519] entry_SYSCALL_64_after_hwframe+0x49/0xbe <4>[ 246.794519] -> #1 (&vm->mutex){+.+.}: <4>[ 246.794519] i915_gem_shrinker_taints_mutex+0x6d/0xe0 [i915] <4>[ 246.794519] i915_address_space_init+0x9f/0x160 [i915] <4>[ 246.794519] i915_ggtt_init_hw+0x55/0x170 [i915] <4>[ 246.794519] i915_driver_probe+0xc9f/0x1620 [i915] <4>[ 246.794519] i915_pci_probe+0x43/0x1b0 [i915] <4>[ 246.794519] pci_device_probe+0x9e/0x120 <4>[ 246.794519] really_probe+0xea/0x3d0 <4>[ 246.794519] driver_probe_device+0x10b/0x120 <4>[ 246.794519] device_driver_attach+0x4a/0x50 <4>[ 246.794519] __driver_attach+0x97/0x130 <4>[ 246.794519] bus_for_each_dev+0x74/0xc0 <4>[ 246.794519] bus_add_driver+0x13f/0x210 <4>[ 246.794519] driver_register+0x56/0xe0 <4>[ 246.794519] do_one_initcall+0x58/0x300 <4>[ 246.794519] do_init_module+0x56/0x1f6 <4>[ 246.794519] load_module+0x25bd/0x2a40 <4>[ 246.794519] __se_sys_finit_module+0xd3/0xf0 <4>[ 246.794519] do_syscall_64+0x55/0x1c0 <4>[ 246.794519] entry_SYSCALL_64_after_hwframe+0x49/0xbe <4>[ 246.794519] -> #0 (&dev->struct_mutex/1){+.+.}: <4>[ 246.794519] __lock_acquire+0x15d8/0x1e90 <4>[ 246.794519] lock_acquire+0xa6/0x1c0 <4>[ 246.794519] __mutex_lock+0x9d/0x9b0 <4>[ 246.794519] userptr_mn_invalidate_range_start+0x18f/0x220 [i915] <4>[ 246.794519] __mmu_notifier_invalidate_range_start+0x85/0x110 <4>[ 246.794519] try_to_unmap_one+0x76b/0x860 <4>[ 246.794519] rmap_walk_anon+0x104/0x280 <4>[ 246.794519] try_to_unmap+0xc0/0xf0 <4>[ 246.794519] shrink_page_list+0x561/0xc10 <4>[ 246.794519] shrink_inactive_list+0x220/0x440 <4>[ 246.794519] shrink_node_memcg+0x36e/0x740 <4>[ 246.794519] shrink_node+0xcb/0x490 <4>[ 246.794519] balance_pgdat+0x241/0x580 <4>[ 246.794519] kswapd+0x16c/0x530 <4>[ 246.794519] kthread+0x119/0x130 <4>[ 246.794519] ret_from_fork+0x24/0x50 <4>[ 246.794519] other info that might help us debug this: <4>[ 246.794519] Chain exists of: &dev->struct_mutex/1 --> &mapping->i_mmap_rwsem --> &anon_vma->rwsem <4>[ 246.794519] Possible unsafe locking scenario: <4>[ 246.794519] CPU0 CPU1 <4>[ 246.794519] ---- ---- <4>[ 246.794519] lock(&anon_vma->rwsem); <4>[ 246.794519] lock(&mapping->i_mmap_rwsem); <4>[ 246.794519] lock(&anon_vma->rwsem); <4>[ 246.794519] lock(&dev->struct_mutex/1); <4>[ 246.794519] *** DEADLOCK *** v2: Say no to mmap_ioctl Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111744 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111870 Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Cc: Daniel Vetter Cc: stable@vger.kernel.org Reviewed-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20190928082546.3473-1-chris@chris-wilson.co.uk (cherry picked from commit a4311745bba9763e3c965643d4531bd5765b0513) Signed-off-by: Rodrigo Vivi Signed-off-by: Greg Kroah-Hartman

drm/i915: Mark contents as dirty on a write fault

2019-10-17T20:47:29Z

commit b925708f28c2b7a3a362d709bd7f77bc75c1daac upstream. Since dropping the set-to-gtt-domain in commit a679f58d0510 ("drm/i915: Flush pages on acquisition"), we no longer mark the contents as dirty on a write fault. This has the issue of us then not marking the pages as dirty on releasing the buffer, which means the contents are not written out to the swap device (should we ever pick that buffer as a victim). Notably, this is visible in the dumb buffer interface used for cursors. Having updated the cursor contents via mmap, and swapped away, if the shrinker should evict the old cursor, upon next reuse, the cursor would be invisible. E.g. echo 80 > /proc/sys/kernel/sysrq ; echo f > /proc/sysrq-trigger Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111541 Fixes: a679f58d0510 ("drm/i915: Flush pages on acquisition") Signed-off-by: Chris Wilson Cc: Matthew Auld Cc: Ville Syrjälä Cc: # v5.2+ Reviewed-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20190920121821.7223-1-chris@chris-wilson.co.uk (cherry picked from commit 5028851cdfdf78dc22eacbc44a0ab0b3f599ee4a) Signed-off-by: Rodrigo Vivi Signed-off-by: Greg Kroah-Hartman

drm/i915: Perform GGTT restore much earlier during resume

2019-10-17T20:47:11Z

commit 6c76a93c453643e11a1063906c7c39168dd8d163 upstream. As soon as we re-enable the various functions within the HW, they may go off and read data via a GGTT offset. Hence, if we have not yet restored the GGTT PTE before then, they may read and even *write* random locations in memory. Detected by DMAR faults during resume. Signed-off-by: Chris Wilson Cc: Mika Kuoppala Cc: Martin Peres Cc: Joonas Lahtinen Cc: stable@vger.kernel.org Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20190909110011.8958-4-chris@chris-wilson.co.uk (cherry picked from commit cec5ca08e36fd18d2939b98055346b3b06f56c6c) Signed-off-by: Rodrigo Vivi Signed-off-by: Greg Kroah-Hartman