This reverts commit 9e0f9464e2ab ("drm/i915/gem: Async GPU relocations only"),
and related commit 7ac2d2536dfa7 ("drm/i915/gem: Delete unused code").
Async GPU relocations are not the path forward, we want to remove
GPU accelerated relocation support eventually when userspace is fixed
to use VM_BIND, and this is the first step towards that. We will keep
async gpu relocations around for now, until userspace is fixed.
Relocation support will be disabled completely on platforms where there
was never any userspace that depends on it, as the hardware doesn't
require it from at least gen9+ onward. For older platforms, the plan
is to use cpu relocations only.
The igt side is fixed in igt commit 39e9aa1032a4e ("tests/i915: Remove
subtests that rely on async relocation behavior").
Chris Wilson [Thu, 6 Aug 2020 16:10:56 +0000 (17:10 +0100)]
drm/i915/gem: Free the fence after a fence-chain lookup failure
If dma_fence_chain_find_seqno() reports an error, it does so in its
preamble before it disposes of the input fence. On handling the
error, we need to drop the reference to the fence.
Chris Wilson [Thu, 6 Aug 2020 10:59:54 +0000 (11:59 +0100)]
drm/i915/gem: Reduce context termination list iteration guard to RCU
As we now protect the timeline list using RCU, we can drop the
timeline->mutex for guarding the list iteration during context close, as
we are searching for an inflight request. Any new request will see the
context is banned and not be submitted. In doing so, pull the checks for
a concurrent submission of the request (notably the
i915_request_completed()) under the engine spinlock, to fully serialise
with __i915_request_submit()). That is in the case of preempt-to-busy
where the request may be completed during the __i915_request_submit(),
we need to be careful that we sample the request status after
serialising so that we don't miss the request the engine is actually
submitting.
Fixes: 4a3174152147 ("drm/i915/gem: Refine occupancy test in kill_context()")
References: d22d2d073ef8 ("drm/i915: Protect i915_request_await_start from early waits") # rcu protection of timeline->requests
References: https://gitlab.freedesktop.org/drm/intel/-/issues/1622
References: https://gitlab.freedesktop.org/drm/intel/-/issues/2158 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200806105954.7766-1-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Chris Wilson [Thu, 6 Aug 2020 14:57:28 +0000 (15:57 +0100)]
drm/i915/selftests: Prevent selecting 0 for our random width/align
When igt_random_offset() is a given a range of [0, PAGE_SIZE], it is
allowed to return 0. However, attempting to use a size of 0 for the
igt_lmem_write_cpu() byte poking, leads to call igt_random_offset() with
a range of [offset, offset + 0] and ask it to find a length of 4 within
it. This triggers the bug on that the requested length should fit within
the range!
Chris Wilson [Sat, 1 Aug 2020 16:02:25 +0000 (17:02 +0100)]
drm/i915/gt: Hold context/request reference while breadcrumbs are active
Currently we hold no actual reference to the request nor context while
they are attached to a breadcrumb. To avoid freeing the request/context
too early, we serialise with cancel-breadcrumbs by taking the irq
spinlock in i915_request_retire(). The alternative is to take a
reference for a new breadcrumb and release it upon signaling; removing
the more frequently hit contention point in i915_request_retire().
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200801160225.6814-2-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
[Joonas: Rebased and reordered into drm-intel-gt-next branch] Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
kmalloc uses power-of-two slab buckets for small allocations (up to a
few pages). Since i915_page_directory is a page of pointers, plus a
couple more, this is rounded up to 8K, and we waste nearly 50% of that
allocation. Long terms this leads to poor memory utilisation, bloating
the kernel footprint, but the problem is exacerbated by our conservative
preallocation scheme for binding VMA. As we are required to allocate all
levels for each vma just in case we need to insert them upon binding,
this leads to a large multiplication factor for a single page vma. By
halving the allocation we need for the page directory structure, we
halve the impact of that factor, bringing workloads that once fitted into
memory, hopefully back to fitting into memory.
We maintain the split between i915_page_directory and i915_page_table as
we only need half the allocation for the lowest, most populous, level.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Cc: Matthew Auld <matthew.auld@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200729164219.5737-3-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Chris Wilson [Wed, 29 Jul 2020 16:42:18 +0000 (17:42 +0100)]
drm/i915/gt: Switch to object allocations for page directories
The GEM object is grossly overweight for the practicality of tracking
large numbers of individual pages, yet it is currently our only
abstraction for tracking DMA allocations. Since those allocations need
to be reserved upfront before an operation, and that we need to break
away from simple system memory, we need to ditch using plain struct page
wrappers.
In the process, we drop the WC mapping as we ended up clflushing
everything anyway due to various issues across a wider range of
platforms. Though in a future step, we need to drop the kmap_atomic
approach which suggests we need to pre-map all the pages and keep them
mapped.
v2: Verify our large scratch page is suitably DMA aligned; and manually
clear the scratch since we are allocating plain struct pages full of
prior content.
Chris Wilson [Wed, 29 Jul 2020 16:42:17 +0000 (17:42 +0100)]
drm/i915: Preallocate stashes for vma page-directories
We need to make the DMA allocations used for page directories to be
performed up front so that we can include those allocations in our
memory reservation pass. The downside is that we have to assume the
worst case, even before we know the final layout, and always allocate
enough page directories for this object, even when there will be overlap.
This unfortunately can be quite expensive, especially as we have to
clear/reset the page directories and DMA pages, but it should only be
required during early phases of a workload when new objects are being
discovered, or after memory/eviction pressure when we need to rebind.
Once we reach steady state, the objects should not be moved and we no
longer need to preallocating the pages tables.
It should be noted that the lifetime for the page directories DMA is
more or less decoupled from individual fences as they will be shared
across objects across timelines.
v2: Only allocate enough PD space for the PTE we may use, we do not need
to allocate PD that will be left as scratch.
v3: Store the shift unto the first PD level to encapsulate the different
PTE counts for gen6/gen8.
Chris Wilson [Fri, 31 Jul 2020 15:48:34 +0000 (16:48 +0100)]
drm/i915/gt: Distinguish the virtual breadcrumbs from the irq breadcrumbs
On the virtual engines, we only use the intel_breadcrumbs for tracking
signaling of stale breadcrumbs from the irq_workers. They do not have
any associated interrupt handling, active requests are passed to a
physical engine and associated breadcrumb interrupt handler. This causes
issues for us as we need to ensure that we do not actually try and
enable interrupts and the powermanagement required for them on the
virtual engine, as they will never be disabled. Instead, let's
specify the physical engine used for interrupt handler on a particular
breadcrumb.
v2: Drop b->irq_armed = true mocking for no interrupt HW
Fixes: 4fe6abb8f513 ("drm/i915/gt: Ignore irq enabling on the virtual engines") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200731154834.8378-4-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Chris Wilson [Fri, 31 Jul 2020 15:48:33 +0000 (16:48 +0100)]
drm/i915/gt: Only transfer the virtual context to the new engine if active
One more complication of preempt-to-busy with respect to the virtual
engine is that we may have retired the last request along the virtual
engine at the same time as preparing to submit the completed request to
a new engine. That submit will be shortcircuited, but not before we have
updated the context with the new register offsets and marked the virtual
engine as bound to the new engine (by calling swap on ve->siblings[]).
As we may have just retired the completed request, we may also be in the
middle of calling virtual_context_exit() to turn off the power management
associated with the virtual engine, and that in turn walks the
ve->siblings[]. If we happen to call swap() on the array as we walk, we
will call intel_engine_pm_put() twice on the same engine.
In this patch, we prevent this by only updating the bound engine after a
successful submission which weeds out the already completed requests.
Alternatively, we could walk a non-volatile array for the pm, such as
using the engine->mask. The small advantage to performing the update
after the submit is that we then only have to do a swap for active
requests.
Fixes: 22b7a426bbe1 ("drm/i915/execlists: Preempt-to-busy")
References: 6d06779e8672 ("drm/i915: Load balancing across a virtual engine" Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: "Nayana, Venkata Ramana" <venkata.ramana.nayana@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200731154834.8378-3-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
After staring at the breadcrumb enabling/cancellation and coming to the
conclusion that the cause of the mysterious stale breadcrumbs must the
act of submitting a completed requests, we can then redirect those
completed requests onto a dedicated signaled_list at the time of
construction and so eliminate intel_engine_transfer_stale_breadcrumbs().
Chris Wilson [Fri, 31 Jul 2020 15:48:31 +0000 (16:48 +0100)]
drm/i915: Remove requirement for holding i915_request.lock for breadcrumbs
Since the breadcrumb enabling/cancelling itself is serialised by the
breadcrumbs.irq_lock, with a bit of care we can remove the outer
serialisation with i915_request.lock for concurrent
dma_fence_enable_signaling(). This has the important side-effect of
eliminating the nested i915_request.lock within request submission.
The challenge in serialisation is around the unsubmission where we take
an active request that wants a breadcrumb on the signaling engine and
put it to sleep. We do not want a concurrent
dma_fence_enable_signaling() to attach a breadcrumb as we unsubmit, so
we must mark the request as no longer active before serialising with the
concurrent enable-signaling.
On retire, we serialise with the concurrent enable-signaling, but
instead of clearing ACTIVE, we mark it as SIGNALED.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200731154834.8378-1-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
[Joonas: Rebased and reordered into drm-intel-gt-next branch] Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Chris Wilson [Fri, 31 Jul 2020 08:50:15 +0000 (09:50 +0100)]
drm/i915: Provide a fastpath for waiting on vma bindings
Before we can execute a request, we must wait for all of its vma to be
bound. This is a frequent operation for which we can optimise away a
few atomic operations (notably a cmpxchg) in lieu of the RCU protection.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Thomas Hellström <thomas.hellstrom@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200731085015.32368-7-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Chris Wilson [Fri, 31 Jul 2020 08:50:14 +0000 (09:50 +0100)]
drm/i915: Reduce locking around i915_active_acquire_preallocate_barrier()
As the conversion between idle-barrier and full i915_active_fence is
already serialised by explicit memory barriers, we can reduce the
spinlock in i915_active_acquire_preallocate_barrier() for finding an
idle-barrier to reuse to an RCU read lock to ensure the fence remains
valid, only taking the spinlock for the update of the rbtree itself.
Chris Wilson [Fri, 31 Jul 2020 08:50:13 +0000 (09:50 +0100)]
drm/i915: Make the stale cached active node available for any timeline
Rather than require the next timeline after idling to match the MRU
before idling, reset the index on the node and allow it to match the
first request. However, this requires cmpxchg(u64) and so is not trivial
on 32b, so for compatibility we just fallback to keeping the cached node
pointing to the MRU timeline.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Thomas Hellström <thomas.hellstrom@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200731085015.32368-5-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Chris Wilson [Fri, 31 Jul 2020 08:50:12 +0000 (09:50 +0100)]
drm/i915: Keep the most recently used active-fence upon discard
Whenever an i915_active idles, we prune its tree of old fence slots to
prevent a gradual leak should it be used to track many, many timelines.
The downside is that we then have to frequently reallocate the rbtree.
A compromise is that we keep the most recently used fence slot, and
reuse that for the next active reference as that is the most likely
timeline to be reused.
Chris Wilson [Fri, 31 Jul 2020 08:50:11 +0000 (09:50 +0100)]
drm/i915: Export a preallocate variant of i915_active_acquire()
Sometimes we have to be very careful not to allocate underneath a mutex
(or spinlock) and yet still want to track activity. Enter
i915_active_acquire_for_context(). This raises the activity counter on
i915_active prior to use and ensures that the fence-tree contains a slot
for the context.
v2: Refactor active_lookup() so it can be called again before/after
locking to resolve contention. Since we protect the rbtree until we
idle, we can do a lockfree lookup, with the caveat that if another
thread performs a concurrent insertion, the rotations from the insert
may cause us to not find our target. A second pass holding the treelock
will find the target if it exists, or the place to perform our
insertion.
Chris Wilson [Fri, 31 Jul 2020 08:50:10 +0000 (09:50 +0100)]
drm/i915: Skip taking acquire mutex for no ref->active callback
If no active callback is defined for i915_active, we do not need to
serialise its enabling with the mutex. We still do only want to call the
debug activate once, and must still serialise with a concurrent retire.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Thomas Hellström <thomas.hellstrom@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200731085015.32368-2-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Chris Wilson [Fri, 31 Jul 2020 10:22:06 +0000 (11:22 +0100)]
drm/i915/selftests: Drop stale timeline constructor assert
Since we pass around encoded parameters to the kernel context
constructor using the ce->timeline pointer, we can no longer assert that
it should be zero for mock timeline construction.
Fixes: d1bf5dd8f6d5 ("drm/i915/gt: Support multiple pinned timelines") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200731102206.6793-1-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
[Joonas: Updated Fixes: link after rebasing and reordering into drm-intel-gt-next branch] Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Chris Wilson [Thu, 30 Jul 2020 13:40:49 +0000 (14:40 +0100)]
drm/i915/gt: Pull release of node->age under the spinlock
We need to ensure that the list is valid prior to marking the node as
retrievable, otherwise we may see two threads compete over the same node
in intel_gt_get_buffer_pool(). If the first thread acquires and releases
the node in the same jiffie, the second thread may then acquire it (as
the jiffie now again matches the expected value) and claim the node
before it is put back into the list.
Chris Wilson [Thu, 30 Jul 2020 18:39:06 +0000 (19:39 +0100)]
drm/i915/gt: Support multiple pinned timelines
We may need to allocate more than one pinned context/timeline for each
engine which can utilise the per-engine HWSP, so we need to give each
a different offset within it.
Chris Wilson [Thu, 30 Jul 2020 09:28:56 +0000 (10:28 +0100)]
drm/i915/gem: Delay tracking the GEM context until it is registered
Avoid exposing a partially constructed context by deferring the
list_add() from the initial construction to the end of registration.
Otherwise, if we peek into the list of contexts from inside debugfs, we
may see the partially constructed context and chase down some dangling
incomplete pointers.
Reported-by: CQ Tang <cq.tang@intel.com> Fixes: 3aa9945a528e ("drm/i915: Separate GEM context construction and registration to userspace")
References: f6e8aa387171 ("drm/i915: Report the number of closed vma held by each context in debugfs") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: CQ Tang <cq.tang@intel.com> Cc: <stable@vger.kernel.org> # v5.2+ Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200730092856.23615-1-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Chris Wilson [Wed, 29 Jul 2020 11:07:56 +0000 (12:07 +0100)]
drm/i915/gt: Fix termination condition for freeing all buffer objects
A last minute change, that unfortunately broke CI so badly it declared
SUCCESS, was to refactor the debug free all buffer pool code to reuse
the normal worker, inverted the termination condition so that it instead
of discarding the nodes, they were all declared young enough and
eligible for reuse.
Fixes: 06b73c2d0b65 ("drm/i915/gt: Delay taking the spinlock for grabbing from the buffer pool") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200729110756.2344-1-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
[Joonas: Updating Fixes: link after rebasing and reordering into drm-intel-gt-next] Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Chris Wilson [Wed, 29 Jul 2020 08:02:45 +0000 (09:02 +0100)]
drm/i915/gt: Delay taking the spinlock for grabbing from the buffer pool
Some very low hanging fruit, but contention on the pool->lock is
noticeable between intel_gt_get_buffer_pool() and pool_retire(), with
the majority of the hold time due to the locked list iteration. If we
make the node itself RCU protected, we can perform the search for an
suitable node just under RCU, reserving taking the lock itself for
claiming the node and manipulating the list.
Chris Wilson [Tue, 28 Jul 2020 15:21:09 +0000 (16:21 +0100)]
drm/i915/gt: Disable preparser around xcs invalidations on tgl
Unlike rcs where we have conclusive evidence from our selftesting that
disabling the preparser before performing the TLB invalidate and
relocations does impact upon the GPU execution, the evidence for the
same requirement on xcs is much more circumstantial. Let's apply the
preparser disable between batches as we invalidate the TLB as a dose of
healthy paranoia, just in case.
References: https://gitlab.freedesktop.org/drm/intel/-/issues/2169 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200728152110.830-1-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Chris Wilson [Tue, 28 Jul 2020 15:20:10 +0000 (16:20 +0100)]
drm/i915/gem: Remove disordered per-file request list for throttling
I915_GEM_THROTTLE dates back to the time before contexts where there was
just a single engine, and therefore a single timeline and request list
globally. That request list was in execution/retirement order, and so
walking it to find a particular aged request made sense and could be
split per file.
That is no more. We now have many timelines with a file, as many as the
user wants to construct (essentially per-engine, per-context). Each of
those run independently and so make the single list futile. Remove the
disordered list, and iterate over all the timelines to find a request to
wait on in each to satisfy the criteria that the CPU is no more than 20ms
ahead of its oldest request.
It should go without saying that the I915_GEM_THROTTLE ioctl is no
longer used as the primary means of throttling, so it makes sense to push
the complication into the ioctl where it only impacts upon its few
irregular users, rather than the execbuf/retire where everybody has to
pay the cost. Fortunately, the few users do not create vast amount of
contexts, so the loops over contexts/engines should be concise.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200728152010.30701-1-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Chris Wilson [Wed, 15 Jul 2020 11:50:51 +0000 (12:50 +0100)]
drm/i915: Soften the tasklet flush frequency before waits
We include a tasklet flush before waiting on a request as a precaution
against the HW being lax in event signaling. We now have a precautionary
flush in the engine's heartbeat and so do not need to be quite so
zealous on every request wait. If we focus on the request, the only
tasklet flush that matters is if there is a delay in submitting this
request to HW, so if the request is not ready to be executed, no
advantage in reducing this wait can be gained by running the tasklet.
And there is little point in doing busy work for no result.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200715115147.11866-10-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Chris Wilson [Thu, 16 Jul 2020 10:07:54 +0000 (11:07 +0100)]
drm/i915: Reduce i915_request.lock contention for i915_request_wait
Currently, we use i915_request_completed() directly in
i915_request_wait() and follow up with a manual invocation of
dma_fence_signal(). This appears to cause a large number of contentions
on i915_request.lock as when the process is woken up after the fence is
signaled by an interrupt, we will then try and call dma_fence_signal()
ourselves while the signaler is still holding the lock.
dma_fence_is_signaled() has the benefit of checking the
DMA_FENCE_FLAG_SIGNALED_BIT prior to calling dma_fence_signal() and so
avoids most of that contention.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Matthew Auld <matthew.auld@intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200716100754.5670-1-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Dave Airlie [Fri, 28 Aug 2020 03:51:30 +0000 (13:51 +1000)]
Merge tag 'drm-intel-next-2020-08-24-1' of git://anongit.freedesktop.org/drm/drm-intel into drm-next
UAPI Changes:
- Introduce a mechanism to extend execbuf2 (Lionel)
- Add syncobj timeline support (Lionel)
Driver Changes:
- Limit stolen mem usage on the compressed frame buffer (Ville)
- Some clean-up around display's cdclk (Ville)
- Some DDI changes for better DP link training according
to spec (Imre)
- Provide the perf pmu.module (Chris)
- Remove dobious Valleyview PCI IDs (Alexei)
- Add new display power saving feature for gen12+ called
HOBL (Jose)
- Move SKL's clock gating w/a to skl_init_clock_gating() (Ville)
- Rocket Lake display additions (Matt)
- Selftest: temporarily downgrade on severity of frequency
scaling tests (Chris)
- Introduce a new display workaround for fixing FLR related
issues on new PCH. (Jose)
- Temporarily disable FBC on TGL. It was the culprit of random
underruns. (Uma).
- Copy default modparams to mock i915_device (Chris)
- Add compiler paranoia for checking HWSP values (Chris)
- Remove useless gen check before calling intel_rps_boost (Chris)
- Fix a null pointer dereference (Chris)
- Add a couple of missing i915_active_fini() (Chris)
- Update TGL display power's bw_buddy table according to
update spec (Matt)
- Fix couple wrong return values (Tianjia)
- Selftest: Avoid passing random 0 into ilog2 (George)
- Many Tiger Lake display fixes and improvements for Type-C and
DP compliance (Imre, Jose)
- Start the addition of PSR2 selective fetch (Jose)
- Update a few DMC and HuC firmware versions (Jose)
- Add gen11+ w/a to fix underuns (Matt)
- Fix cmd parser desc matching with mask (Mika)
Dave Airlie [Fri, 28 Aug 2020 02:37:46 +0000 (12:37 +1000)]
Merge tag 'drm-misc-next-2020-08-27' of git://anongit.freedesktop.org/drm/drm-misc into drm-next
drm-misc-next for 5.10:
UAPI Changes:
Cross-subsystem Changes:
Core Changes:
- ttm: various cleanups and reworks of the API
Driver Changes:
- ast: various cleanups
- gma500: A few fixes, conversion to GPIOd API
- hisilicon: Change of maintainer, various reworks
- ingenic: Clock handling and formats support improvements
- mcde: improvements to the DSI support
- mgag200: Support G200 desktop cards
- mxsfb: Support the i.MX7 and i.MX8M and the alpha plane
- panfrost: support devfreq
- ps8640: Retrieve the EDID from eDP control, misc improvements
- tidss: Add a workaround for AM65xx YUV formats handling
- virtio: a few cleanups, support for virtio-gpu exported resources
- bridges: Support the chained bridges on more drivers,
new bridges: Toshiba TC358762, Toshiba TC358775, Lontium LT9611
- panels: Convert to dev_ based logging, read orientation from the DT,
various fixes, new panels: Mantix MLAF057WE51-X, Chefree CH101OLHLWH-002,
Powertip PH800480T013, KingDisplay KD116N21-30NV-A010
drm/bridge: ps8640: Print an error if VDO control fails
Print an error message inside ps8640_bridge_vdo_control() function when
it fails so we can simplify a bit the callers, they will only need to
check the error code.
drm/bridge: ps8640: Return an error for incorrect attach flags
Bridge drivers that implement the new model only shall return an error
from their attach() handler when the DRM_BRIDGE_ATTACH_NO_CONNECTOR flag
is not set. So make sure we return an error because only the new
drm_bridge model is supported.
drm/bridge_connector: Set default status connected for eDP connectors
In an eDP application, HPD is not required and on most bridge chips
useless. If HPD is not used, we need to set initial status as connected,
otherwise the connector created by the drm_bridge_connector API remains
in an unknown state.
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> Reviewed-by: Bilal Wasim <bwasim.lkml@gmail.com> Tested-by: Bilal Wasim <bwasim.lkml@gmail.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20200826081526.674866-2-enric.balletbo@collabora.com
Linus Torvalds [Sun, 23 Aug 2020 18:37:23 +0000 (11:37 -0700)]
Merge tag 'powerpc-5.9-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
- Add perf support for emitting extended registers for power10.
- A fix for CPU hotplug on pseries, where on large/loaded systems we
may not wait long enough for the CPU to be offlined, leading to
crashes.
- Addition of a raw cputable entry for Power10, which is not required
to boot, but is required to make our PMU setup work correctly in
guests.
- Three fixes for the recent changes on 32-bit Book3S to move modules
into their own segment for strict RWX.
- A fix for a recent change in our powernv PCI code that could lead to
crashes.
- A change to our perf interrupt accounting to avoid soft lockups when
using some events, found by syzkaller.
- A change in the way we handle power loss events from the hypervisor
on pseries. We no longer immediately shut down if we're told we're
running on a UPS.
- A few other minor fixes.
Thanks to Alexey Kardashevskiy, Andreas Schwab, Aneesh Kumar K.V, Anju T
Sudhakar, Athira Rajeev, Christophe Leroy, Frederic Barrat, Greg Kurz,
Kajol Jain, Madhavan Srinivasan, Michael Neuling, Michael Roth,
Nageswara R Sastry, Oliver O'Halloran, Thiago Jung Bauermann,
Vaidyanathan Srinivasan, Vasant Hegde.
* tag 'powerpc-5.9-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/perf/hv-24x7: Move cpumask file to top folder of hv-24x7 driver
powerpc/32s: Fix module loading failure when VMALLOC_END is over 0xf0000000
powerpc/pseries: Do not initiate shutdown when system is running on UPS
powerpc/perf: Fix soft lockups due to missed interrupt accounting
powerpc/powernv/pci: Fix possible crash when releasing DMA resources
powerpc/pseries/hotplug-cpu: wait indefinitely for vCPU death
powerpc/32s: Fix is_module_segment() when MODULES_VADDR is defined
powerpc/kasan: Fix KASAN_SHADOW_START on BOOK3S_32
powerpc/fixmap: Fix the size of the early debug area
powerpc/pkeys: Fix build error with PPC_MEM_KEYS disabled
powerpc/kernel: Cleanup machine check function declarations
powerpc: Add POWER10 raw mode cputable entry
powerpc/perf: Add extended regs support for power10 platform
powerpc/perf: Add support for outputting extended regs in perf intr_regs
powerpc: Fix P10 PVR revision in /proc/cpuinfo for SMT4 cores
Linus Torvalds [Sun, 23 Aug 2020 18:21:16 +0000 (11:21 -0700)]
Merge tag 'x86-urgent-2020-08-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fix from Thomas Gleixner:
"A single fix for x86 which removes the RDPID usage from the paranoid
entry path and unconditionally uses LSL to retrieve the CPU number.
RDPID depends on MSR_TSX_AUX. KVM has an optmization to avoid
expensive MRS read/writes on VMENTER/EXIT. It caches the MSR values
and restores them either when leaving the run loop, on preemption or
when going out to user space. MSR_TSX_AUX is part of that lazy MSR
set, so after writing the guest value and before the lazy restore any
exception using the paranoid entry will read the guest value and use
it as CPU number to retrieve the GSBASE value for the current CPU when
FSGSBASE is enabled. As RDPID is only used in that particular entry
path, there is no reason to burden VMENTER/EXIT with two extra MSR
writes. Remove the RDPID optimization, which is not even backed by
numbers from the paranoid entry path instead"
* tag 'x86-urgent-2020-08-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/entry/64: Do not use RDPID in paranoid entry to accomodate KVM
Linus Torvalds [Sun, 23 Aug 2020 18:15:14 +0000 (11:15 -0700)]
Merge tag 'perf-urgent-2020-08-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 perf fix from Thomas Gleixner:
"A single update for perf on x86 which has support for the broken down
bandwith counters"
* tag 'perf-urgent-2020-08-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel/uncore: Add BW counters for GT, IA and IO breakdown
Linus Torvalds [Sun, 23 Aug 2020 18:05:47 +0000 (11:05 -0700)]
Merge tag 'core-urgent-2020-08-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull entry fix from Thomas Gleixner:
"A single bug fix for the common entry code.
The transcription of the x86 version messed up the reload of the
syscall number from pt_regs after ptrace and seccomp which breaks
syscall number rewriting"
* tag 'core-urgent-2020-08-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
core/entry: Respect syscall number rewrites
Linus Torvalds [Sun, 23 Aug 2020 17:57:19 +0000 (10:57 -0700)]
Merge tag 'edac_urgent_for_v5.9_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras
Pull EDAC fix from Borislav Petkov:
"A single fix correcting a reversed error severity determination check
which lead to a recoverable error getting marked as fatal, by Tony
Luck"
* tag 'edac_urgent_for_v5.9_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras:
EDAC/{i7core,sb,pnd2,skx}: Fix error event severity
Pull networking fixes from David Miller:
"Nothing earth shattering here, lots of small fixes (f.e. missing RCU
protection, bad ref counting, missing memset(), etc.) all over the
place:
1) Use get_file_rcu() in task_file iterator, from Yonghong Song.
2) There are two ways to set remote source MAC addresses in macvlan
driver, but only one of which validates things properly. Fix this.
From Alvin Šipraga.
3) Missing of_node_put() in gianfar probing, from Sumera
Priyadarsini.
4) Preserve device wanted feature bits across multiple netlink
ethtool requests, from Maxim Mikityanskiy.
5) Fix rcu_sched stall in task and task_file bpf iterators, from
Yonghong Song.
6) Avoid reset after device destroy in ena driver, from Shay
Agroskin.
7) Missing memset() in netlink policy export reallocation path, from
Johannes Berg.
8) Fix info leak in __smc_diag_dump(), from Peilin Ye.
9) Decapsulate ECN properly for ipv6 in ipv4 tunnels, from Mark
Tomlinson.
10) Fix number of data stream negotiation in SCTP, from David Laight.
11) Fix double free in connection tracker action module, from Alaa
Hleihel.
12) Don't allow empty NHA_GROUP attributes, from Nikolay Aleksandrov"
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (46 commits)
net: nexthop: don't allow empty NHA_GROUP
bpf: Fix two typos in uapi/linux/bpf.h
net: dsa: b53: check for timeout
tipc: call rcu_read_lock() in tipc_aead_encrypt_done()
net/sched: act_ct: Fix skb double-free in tcf_ct_handle_fragments() error flow
net: sctp: Fix negotiation of the number of data streams.
dt-bindings: net: renesas, ether: Improve schema validation
gre6: Fix reception with IP6_TNL_F_RCV_DSCP_COPY
hv_netvsc: Fix the queue_mapping in netvsc_vf_xmit()
hv_netvsc: Remove "unlikely" from netvsc_select_queue
bpf: selftests: global_funcs: Check err_str before strstr
bpf: xdp: Fix XDP mode when no mode flags specified
selftests/bpf: Remove test_align leftovers
tools/resolve_btfids: Fix sections with wrong alignment
net/smc: Prevent kernel-infoleak in __smc_diag_dump()
sfc: fix build warnings on 32-bit
net: phy: mscc: Fix a couple of spelling mistakes "spcified" -> "specified"
libbpf: Fix map index used in error message
net: gemini: Fix missing free_netdev() in error path of gemini_ethernet_port_probe()
net: atlantic: Use readx_poll_timeout() for large timeout
...
Linus Torvalds [Sun, 23 Aug 2020 00:11:38 +0000 (17:11 -0700)]
Merge branch 'work.epoll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull epoll fixes from Al Viro:
"Fix reference counting and clean up exit paths"
* 'work.epoll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
do_epoll_ctl(): clean the failure exits up a bit
epoll: Keep a reference on files added to the check list
Marc Zyngier [Wed, 19 Aug 2020 16:12:17 +0000 (17:12 +0100)]
epoll: Keep a reference on files added to the check list
When adding a new fd to an epoll, and that this new fd is an
epoll fd itself, we recursively scan the fds attached to it
to detect cycles, and add non-epool files to a "check list"
that gets subsequently parsed.
However, this check list isn't completely safe when deletions
can happen concurrently. To sidestep the issue, make sure that
a struct file placed on the check list sees its f_count increased,
ensuring that a concurrent deletion won't result in the file
disapearing from under our feet.
Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Currently the nexthop code will use an empty NHA_GROUP attribute, but it
requires at least 1 entry in order to function properly. Otherwise we
end up derefencing null or random pointers all over the place due to not
having any nh_grp_entry members allocated, nexthop code relies on having at
least the first member present. Empty NHA_GROUP doesn't make any sense so
just disallow it.
Also add a WARN_ON for any future users of nexthop_create_group().
CC: David Ahern <dsahern@gmail.com> Fixes: 430a049190de ("nexthop: Add support for nexthop groups") Reported-by: syzbot+a61aa19b0c14c8770bd9@syzkaller.appspotmail.com Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linus Torvalds [Sat, 22 Aug 2020 17:22:44 +0000 (10:22 -0700)]
Merge tag 'kbuild-fixes-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild fixes from Masahiro Yamada:
- move -Wsign-compare warning from W=2 to W=3
- fix the keyword _restrict to __restrict in genksyms
- fix more bugs in qconf
* tag 'kbuild-fixes-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kconfig: qconf: replace deprecated QString::sprintf() with QTextStream
kconfig: qconf: remove redundant help in the info view
kconfig: qconf: remove qInfo() to get back Qt4 support
kconfig: qconf: remove unused colNr
kconfig: qconf: fix the popup menu in the ConfigInfoView window
kconfig: qconf: fix signal connection to invalid slots
genksyms: keywords: Use __restrict not _restrict
kbuild: remove redundant patterns in filter/filter-out
extract-cert: add static to local data
Makefile.extrawarn: Move sign-compare from W=2 to W=3
Linus Torvalds [Sat, 22 Aug 2020 17:17:36 +0000 (10:17 -0700)]
Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Catalin Marinas:
- Allow booting of late secondary CPUs affected by erratum 1418040
(currently they are parked if none of the early CPUs are affected by
this erratum).
- Add the 32-bit vdso Makefile to the vdso_install rule so that 'make
vdso_install' installs the 32-bit compat vdso when it is compiled.
- Print a warning that untrusted guests without a CPU erratum
workaround (Cortex-A57 832075) may deadlock the affected system.
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
ARM64: vdso32: Install vdso32 from vdso_install
KVM: arm64: Print warning when cpu erratum can cause guests to deadlock
arm64: Allow booting of late CPUs affected by erratum 1418040
arm64: Move handling of erratum 1418040 into C code
Linus Torvalds [Sat, 22 Aug 2020 17:03:05 +0000 (10:03 -0700)]
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fixes from Paolo Bonzini:
- PAE and PKU bugfixes for x86
- selftests fix for new binutils
- MMU notifier fix for arm64
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set
KVM: Pass MMU notifier range flags to kvm_unmap_hva_range()
kvm: x86: Toggling CR4.PKE does not load PDPTEs in PAE mode
kvm: x86: Toggling CR4.SMAP does not load PDPTEs in PAE mode
KVM: x86: fix access code passed to gva_to_gpa
selftests: kvm: Use a shorter encoding to clear RAX
Linus Torvalds [Sat, 22 Aug 2020 16:56:42 +0000 (09:56 -0700)]
Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull SCSI fixes from James Bottomley:
"23 fixes in 5 drivers (qla2xxx, ufs, scsi_debug, fcoe, zfcp). The bulk
of the changes are in qla2xxx and ufs and all are mostly small and
definitely don't impact the core"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (23 commits)
Revert "scsi: qla2xxx: Disable T10-DIF feature with FC-NVMe during probe"
Revert "scsi: qla2xxx: Fix crash on qla2x00_mailbox_command"
scsi: qla2xxx: Fix null pointer access during disconnect from subsystem
scsi: qla2xxx: Check if FW supports MQ before enabling
scsi: qla2xxx: Fix WARN_ON in qla_nvme_register_hba
scsi: qla2xxx: Allow ql2xextended_error_logging special value 1 to be set anytime
scsi: qla2xxx: Reduce noisy debug message
scsi: qla2xxx: Fix login timeout
scsi: qla2xxx: Indicate correct supported speeds for Mezz card
scsi: qla2xxx: Flush I/O on zone disable
scsi: qla2xxx: Flush all sessions on zone disable
scsi: qla2xxx: Use MBX_TOV_SECONDS for mailbox command timeout values
scsi: scsi_debug: Fix scp is NULL errors
scsi: zfcp: Fix use-after-free in request timeout handlers
scsi: ufs: No need to send Abort Task if the task in DB was cleared
scsi: ufs: Clean up completed request without interrupt notification
scsi: ufs: Improve interrupt handling for shared interrupts
scsi: ufs: Fix interrupt error message for shared interrupts
scsi: ufs-pci: Add quirk for broken auto-hibernate for Intel EHL
scsi: ufs-mediatek: Fix incorrect time to wait link status
...
Linus Torvalds [Sat, 22 Aug 2020 16:31:11 +0000 (09:31 -0700)]
Merge tag 'devicetree-fixes-for-5.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux
Pull devicetree fixes from Rob Herring:
"Another set of DT fixes:
- restore range parsing error check
- workaround PCI range parsing with missing 'device_type' now
required
- correct description of 'phy-connection-type'
- fix erroneous matching on 'snps,dw-pcie' by 'intel,lgm-pcie' schema
- a couple of grammar and whitespace fixes
- update Shawn Guo's email"
* tag 'devicetree-fixes-for-5.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
dt-bindings: vendor-prefixes: Remove trailing whitespace
dt-bindings: net: correct description of phy-connection-type
dt-bindings: PCI: intel,lgm-pcie: Fix matching on all snps,dw-pcie instances
of: address: Work around missing device_type property in pcie nodes
dt: writing-schema: Miscellaneous grammar fixes
dt-bindings: Use Shawn Guo's preferred e-mail for i.MX bindings
of/address: check for invalid range.cpu_addr
Will Deacon [Tue, 11 Aug 2020 10:27:25 +0000 (11:27 +0100)]
KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set
When an MMU notifier call results in unmapping a range that spans multiple
PGDs, we end up calling into cond_resched_lock() when crossing a PGD boundary,
since this avoids running into RCU stalls during VM teardown. Unfortunately,
if the VM is destroyed as a result of OOM, then blocking is not permitted
and the call to the scheduler triggers the following BUG():
Will Deacon [Tue, 11 Aug 2020 10:27:24 +0000 (11:27 +0100)]
KVM: Pass MMU notifier range flags to kvm_unmap_hva_range()
The 'flags' field of 'struct mmu_notifier_range' is used to indicate
whether invalidate_range_{start,end}() are permitted to block. In the
case of kvm_mmu_notifier_invalidate_range_start(), this field is not
forwarded on to the architecture-specific implementation of
kvm_unmap_hva_range() and therefore the backend cannot sensibly decide
whether or not to block.
Add an extra 'flags' parameter to kvm_unmap_hva_range() so that
architectures are aware as to whether or not they are permitted to block.
Cc: <stable@vger.kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: James Morse <james.morse@arm.com> Signed-off-by: Will Deacon <will@kernel.org>
Message-Id: <20200811102725.7121-2-will@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Linus Torvalds [Fri, 21 Aug 2020 21:59:16 +0000 (14:59 -0700)]
Merge tag 'io_uring-5.9-2020-08-21' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe:
- Make sure the head link cancelation includes async work
- Get rid of kiocb_wait_page_queue_init(), makes no sense to have it as
a separate function since you moved it into io_uring itself
- io_import_iovec cleanups (Pavel, me)
- Use system_unbound_wq for ring exit work, to avoid spawning tons of
these if we have tons of rings exiting at the same time
- Fix req->flags overflow flag manipulation (Pavel)
* tag 'io_uring-5.9-2020-08-21' of git://git.kernel.dk/linux-block:
io_uring: kill extra iovec=NULL in import_iovec()
io_uring: comment on kfree(iovec) checks
io_uring: fix racy req->flags modification
io_uring: use system_unbound_wq for ring exit work
io_uring: cleanup io_import_iovec() of pre-mapped request
io_uring: get rid of kiocb_wait_page_queue_init()
io_uring: find and cancel head link async work on files exit
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
mm, page_alloc: fix core hung in free_pcppages_bulk()
mm: include CMA pages in lowmem_reserve at boot
squashfs: avoid bio_alloc() failure with 1Mbyte blocks
uprobes: __replace_page() avoid BUG in munlock_vma_page()
kernel/relay.c: fix memleak on destroy relay channel
romfs: fix uninitialized memory leak in romfs_dev_read()
mm/rodata_test.c: fix missing function declaration
mm/vunmap: add cond_resched() in vunmap_pmd_range
khugepaged: adjust VM_BUG_ON_MM() in __khugepaged_enter()
hugetlb_cgroup: convert comma to semicolon
mailmap: add Andi Kleen
Linus Torvalds [Fri, 21 Aug 2020 19:32:42 +0000 (12:32 -0700)]
Merge tag 'riscv-for-linus-5.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V fixes from Palmer Dabbelt:
- The CLINT driver has been split in two: one to handle the M-mode
CLINT (memory mapped and used on NOMMU systems) and one to handle the
S-mode CLINT (via SBI).
- The addition of SiFive's drivers to rv32_defconfig
* tag 'riscv-for-linus-5.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
riscv: Add SiFive drivers to rv32_defconfig
dt-bindings: timer: Add CLINT bindings
RISC-V: Remove CLINT related code from timer and arch
clocksource/drivers: Add CLINT timer driver
RISC-V: Add mechanism to provide custom IPI operations
Linus Torvalds [Fri, 21 Aug 2020 19:28:33 +0000 (12:28 -0700)]
Merge tag 'for-linus-5.9-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fixes from Juergen Gross:
"One build fix and a minor fix for suppressing a useless warning when
booting a Xen dom0 via UEFI"
* tag 'for-linus-5.9-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
Fix build error when CONFIG_ACPI is not set/enabled:
efi: avoid error message when booting under Xen
Linus Torvalds [Fri, 21 Aug 2020 19:26:58 +0000 (12:26 -0700)]
Merge tag 'pm-5.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"These fix a few issues in the operating performance points (OPP)
framework.
Specifics:
- Fix re-enabling of resources in dev_pm_opp_set_rate() (Rajendra
Nayak)
- Fix OPP table reference counting in error paths (Stephen Boyd)"
* tag 'pm-5.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
opp: Enable resources again if they were disabled earlier
opp: Put opp table in dev_pm_opp_set_rate() if _set_opp_bw() fails
opp: Put opp table in dev_pm_opp_set_rate() for empty tables
Tom Rix [Fri, 21 Aug 2020 13:56:00 +0000 (06:56 -0700)]
net: dsa: b53: check for timeout
clang static analysis reports this problem
b53_common.c:1583:13: warning: The left expression of the compound
assignment is an uninitialized value. The computed value will
also be garbage
ent.port &= ~BIT(port);
~~~~~~~~ ^
ent is set by a successful call to b53_arl_read(). Unsuccessful
calls are caught by an switch statement handling specific returns.
b32_arl_read() calls b53_arl_op_wait() which fails with the
unhandled -ETIMEDOUT.
So add -ETIMEDOUT to the switch statement. Because
b53_arl_op_wait() already prints out a message, do not add another
one.
Fixes: 1da6df85c6fb ("net: dsa: b53: Implement ARL add/del/dump operations") Signed-off-by: Tom Rix <trix@redhat.com> Acked-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linus Torvalds [Fri, 21 Aug 2020 18:03:38 +0000 (11:03 -0700)]
Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"Improvements to ext4's block allocator performance for very large file
systems, especially when the file system or files which are highly
fragmented. There is a new mount option, prefetch_block_bitmaps which
will pull in the block bitmaps and set up the in-memory buddy bitmaps
when the file system is initially mounted.
Beyond that, a lot of bug fixes and cleanups. In particular, a number
of changes to make ext4 more robust in the face of write errors or
file system corruptions"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (46 commits)
ext4: limit the length of per-inode prealloc list
ext4: reorganize if statement of ext4_mb_release_context()
ext4: add mb_debug logging when there are lost chunks
ext4: Fix comment typo "the the".
jbd2: clean up checksum verification in do_one_pass()
ext4: change to use fallthrough macro
ext4: remove unused parameter of ext4_generic_delete_entry function
mballoc: replace seq_printf with seq_puts
ext4: optimize the implementation of ext4_mb_good_group()
ext4: delete invalid comments near ext4_mb_check_limits()
ext4: fix typos in ext4_mb_regular_allocator() comment
ext4: fix checking of directory entry validity for inline directories
fs: prevent BUG_ON in submit_bh_wbc()
ext4: correctly restore system zone info when remount fails
ext4: handle add_system_zone() failure in ext4_setup_system_zone()
ext4: fold ext4_data_block_valid_rcu() into the caller
ext4: check journal inode extents more carefully
ext4: don't allow overlapping system zones
ext4: handle error of ext4_setup_system_zone() on remount
ext4: delete the invalid BUGON in ext4_mb_load_buddy_gfp()
...
David Howells [Fri, 21 Aug 2020 09:15:12 +0000 (10:15 +0100)]
afs: Fix NULL deref in afs_dynroot_depopulate()
If an error occurs during the construction of an afs superblock, it's
possible that an error occurs after a superblock is created, but before
we've created the root dentry. If the superblock has a dynamic root
(ie. what's normally mounted on /afs), the afs_kill_super() will call
afs_dynroot_depopulate() to unpin any created dentries - but this will
oops if the root hasn't been created yet.
Fix this by skipping that bit of code if there is no root dentry.
Linus Torvalds [Fri, 21 Aug 2020 17:14:16 +0000 (10:14 -0700)]
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma
Pull rdma fixes from Jason Gunthorpe:
"One regression from 5.8 and a few bugs from earlier kernels:
- Various spelling corrections in kernel prints
- Bug fixes in hfi1 and bntx_re
- Revert a 5.8 patch in hns
- Batch update for Mellanox and Cumulus maintainers emails"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
MAINTAINERS: Update Mellanox and Cumulus Network addresses to new domain
Revert "RDMA/hns: Reserve one sge in order to avoid local length error"
RDMA/hfi1: Correct an interlock issue for TID RDMA WRITE request
RDMA/bnxt_re: Do not add user qps to flushlist
RDMA/core: Fix spelling mistake "Could't" -> "Couldn't"
RDMA/usnic: Fix spelling mistake "transistion" -> "transition"
RDMA/hns: Fix spelling mistake "epmty" -> "empty"
Linus Torvalds [Fri, 21 Aug 2020 17:07:54 +0000 (10:07 -0700)]
Merge tag 'sound-5.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull sound fixes from Takashi Iwai:
"A collection of small fixes over several drivers, but all are driver-
specific and nothing looks scary.
Slightly large changes are seen in ASoC qcom driver for the bugs that
were revealed by the recent ASoC core change to report the invalid
register access errors. Also ASoC fsl got a slight intensive change
for the distortion fix.
Others are only trivial fixes or device-specific quirks"
* tag 'sound-5.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (25 commits)
ALSA: hda: avoid reset of sdo_limit
ALSA: hda/realtek: Add quirk for Samsung Galaxy Book Ion
ALSA: usb-audio: ignore broken processing/extension unit
ASoC: intel: Fix memleak in sst_media_open
ASoC: wm8994: Avoid attempts to read unreadable registers
ASoC: msm8916-wcd-analog: fix register Interrupt offset
ASoC: wm8994: Prevent access to invalid VU register bits on WM1811
ALSA: hda/realtek: Add model alc298-samsung-headphone
ALSA: usb-audio: Update documentation comment for MS2109 quirk
ALSA: isa: fix spelling mistakes in the comments
ALSA: usb-audio: Add capture support for Saffire 6 (USB 1.1)
ALSA: hda/realtek: Add quirk for Samsung Galaxy Flex Book
ASoC: q6routing: add dummy register read/write function
ASoC: q6afe-dai: mark all widgets registers as SND_SOC_NOPM
ASoC: Make soc_component_read() returning an error code again
ASoC: amd: Replacing component->name with codec_dai->name.
ASoC: fsl: Fix unused variable warning
ASoC: tegra: tegra210_i2s: Fix compile warning with CONFIG_PM=n
ASoC: tegra: tegra210_dmic: Fix compile warning with CONFIG_PM=n
ASoC: tegra: tegra210_ahub: Fix compile warning with CONFIG_PM=n
...
Linus Torvalds [Fri, 21 Aug 2020 17:02:44 +0000 (10:02 -0700)]
Merge tag 'drm-fixes-2020-08-21' of git://anongit.freedesktop.org/drm/drm
Pull drm fixes from Dave Airlie:
"Regular fixes pull for rc2. Usual rc2 doesn't seem too busy, mainly
i915 and amdgpu. I'd expect the usual uptick for rc3.
amdgpu:
- Fix allocation size
- SR-IOV fixes
- Vega20 SMU feature state caching fix
- Fix custom pptable handling
- Arcturus golden settings update
- Several display fixes
- Fixes for Navy Flounder
- Misc display fixes
- RAS fix
amdkfd:
- SDMA fix for renoir
i915:
- Fix device parameter usage for selftest mock i915 device
- Fix LPSP capability debugfs NULL dereference
- Fix buddy register pagemask table
- Fix intel_atomic_check() non-negative return value
- Fix selftests passing a random 0 into ilog2()
- Fix TGL power well enable/disable ordering
- Switch to PMU module refcounting
- GVT fixes
virtio:
- Add missing dma_fence_put() in virtio_gpu_execbuffer_ioctl()
- Fix memory leak in virtio_gpu_cleanup_object()"
* tag 'drm-fixes-2020-08-21' of git://anongit.freedesktop.org/drm/drm: (34 commits)
Revert "drm/amdgpu: disable gfxoff for navy_flounder"
drm/i915/tgl: Make sure TC-cold is blocked before enabling TC AUX power wells
drm/i915/selftests: Avoid passing a random 0 into ilog2
drm/i915: Fix wrong return value in intel_atomic_check()
drm/i915: Update bw_buddy pagemask table
drm/i915/display: Check for an LPSP encoder before dereferencing
drm/i915: Copy default modparams to mock i915_device
drm/i915: Provide the perf pmu.module
drm/amd/display: fix pow() crashing when given base 0
drm/amd/display: Reset scrambling on Test Pattern
drm/amd/display: fix dcn3 wide timing dsc validation
drm/amd/display: Fix DFPstate hang due to view port changed
drm/amd/display: Assign correct left shift
drm/amd/display: Call DMUB for eDP power control
drm/amdkfd: fix the wrong sdma instance query for renoir
drm/amdgpu: parse ta firmware for navy_flounder
drm/amdgpu: fix NULL pointer access issue when unloading driver
drm/amdgpu: fix uninit-value in arcturus_log_thermal_throttling_event()
drm/amdgpu: disable gfxoff for navy_flounder
drm/amdgpu/display: use GFP_ATOMIC in dcn20_validate_bandwidth_internal
...
mm, page_alloc: fix core hung in free_pcppages_bulk()
The following race is observed with the repeated online, offline and a
delay between two successive online of memory blocks of movable zone.
P1 P2
Online the first memory block in
the movable zone. The pcp struct
values are initialized to default
values,i.e., pcp->high = 0 &
pcp->batch = 1.
Allocate the pages from the
movable zone.
Try to Online the second memory
block in the movable zone thus it
entered the online_pages() but yet
to call zone_pcp_update().
This process is entered into
the exit path thus it tries
to release the order-0 pages
to pcp lists through
free_unref_page_commit().
As pcp->high = 0, pcp->count = 1
proceed to call the function
free_pcppages_bulk().
Update the pcp values thus the
new pcp values are like, say,
pcp->high = 378, pcp->batch = 63.
Read the pcp's batch value using
READ_ONCE() and pass the same to
free_pcppages_bulk(), pcp values
passed here are, batch = 63,
count = 1.
Since num of pages in the pcp
lists are less than ->batch,
then it will stuck in
while(list_empty(list)) loop
with interrupts disabled thus
a core hung.
Avoid this by ensuring free_pcppages_bulk() is called with proper count of
pcp list pages.
The mentioned race is some what easily reproducible without [1] because
pcp's are not updated for the first memory block online and thus there is
a enough race window for P2 between alloc+free and pcp struct values
update through onlining of second memory block.
With [1], the race still exists but it is very narrow as we update the pcp
struct values for the first memory block online itself.
This is not limited to the movable zone, it could also happen in cases
with the normal zone (e.g., hotplug to a node that only has DMA memory, or
no other memory yet).
Doug Berger [Fri, 21 Aug 2020 00:42:24 +0000 (17:42 -0700)]
mm: include CMA pages in lowmem_reserve at boot
The lowmem_reserve arrays provide a means of applying pressure against
allocations from lower zones that were targeted at higher zones. Its
values are a function of the number of pages managed by higher zones and
are assigned by a call to the setup_per_zone_lowmem_reserve() function.
The function is initially called at boot time by the function
init_per_zone_wmark_min() and may be called later by accesses of the
/proc/sys/vm/lowmem_reserve_ratio sysctl file.
The function init_per_zone_wmark_min() was moved up from a module_init to
a core_initcall to resolve a sequencing issue with khugepaged.
Unfortunately this created a sequencing issue with CMA page accounting.
The CMA pages are added to the managed page count of a zone when
cma_init_reserved_areas() is called at boot also as a core_initcall. This
makes it uncertain whether the CMA pages will be added to the managed page
counts of their zones before or after the call to
init_per_zone_wmark_min() as it becomes dependent on link order. With the
current link order the pages are added to the managed count after the
lowmem_reserve arrays are initialized at boot.
This means the lowmem_reserve values at boot may be lower than the values
used later if /proc/sys/vm/lowmem_reserve_ratio is accessed even if the
ratio values are unchanged.
In many cases the difference is not significant, but for example
an ARM platform with 1GB of memory and the following memory layout
cma: Reserved 256 MiB at 0x0000000030000000
Zone ranges:
DMA [mem 0x0000000000000000-0x000000002fffffff]
Normal empty
HighMem [mem 0x0000000030000000-0x000000003fffffff]
would result in 0 lowmem_reserve for the DMA zone. This would allow
userspace to deplete the DMA zone easily.
Funnily enough
$ cat /proc/sys/vm/lowmem_reserve_ratio
would fix up the situation because as a side effect it forces
setup_per_zone_lowmem_reserve.
This commit breaks the link order dependency by invoking
init_per_zone_wmark_min() as a postcore_initcall so that the CMA pages
have the chance to be properly accounted in their zone(s) and allowing
the lowmem_reserve arrays to receive consistent values.
Fixes: bc22af74f271 ("mm: update min_free_kbytes from khugepaged after core initialization") Signed-off-by: Doug Berger <opendmb@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Jason Baron <jbaron@akamai.com> Cc: David Rientjes <rientjes@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/1597423766-27849-1-git-send-email-opendmb@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Phillip Lougher [Fri, 21 Aug 2020 00:42:21 +0000 (17:42 -0700)]
squashfs: avoid bio_alloc() failure with 1Mbyte blocks
This is a regression introduced by the patch "migrate from ll_rw_block
usage to BIO".
Bio_alloc() is limited to 256 pages (1 Mbyte). This can cause a failure
when reading 1 Mbyte block filesystems. The problem is a datablock can be
fully (or almost uncompressed), requiring 256 pages, but, because blocks
are not aligned to page boundaries, it may require 257 pages to read.
Bio_kmalloc() can handle 1024 pages, and so use this for the edge
condition.
Fixes: 93e72b3c612a ("squashfs: migrate from ll_rw_block usage to BIO") Reported-by: Nicolas Prochazka <nicolas.prochazka@gmail.com> Reported-by: Tomoatsu Shimada <shimada@walbrix.com> Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Guenter Roeck <groeck@chromium.org> Cc: Philippe Liard <pliard@google.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Adrien Schildknecht <adrien+dev@schischi.me> Cc: Daniel Rosenberg <drosen@google.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200815035637.15319-1-phillip@squashfs.org.uk Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hugh Dickins [Fri, 21 Aug 2020 00:42:17 +0000 (17:42 -0700)]
uprobes: __replace_page() avoid BUG in munlock_vma_page()
syzbot crashed on the VM_BUG_ON_PAGE(PageTail) in munlock_vma_page(), when
called from uprobes __replace_page(). Which of many ways to fix it?
Settled on not calling when PageCompound (since Head and Tail are equals
in this context, PageCompound the usual check in uprobes.c, and the prior
use of FOLL_SPLIT_PMD will have cleared PageMlocked already).
Fixes: 5a52c9df62b4 ("uprobe: use FOLL_SPLIT_PMD instead of FOLL_SPLIT") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Song Liu <songliubraving@fb.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: <stable@vger.kernel.org> [5.4+] Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008161338360.20413@eggly.anvils Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
'chan->buf' is malloced in relay_open() by alloc_percpu() but not free
while destroy the relay channel. Fix it by adding free_percpu() before
return from relay_destroy_channel().
Fixes: 017c59c042d0 ("relay: Use per CPU constructs for the relay channel buffer pointers") Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: David Rientjes <rientjes@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Daniel Axtens <dja@axtens.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Akash Goel <akash.goel@intel.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200817122826.48518-1-weiyongjun1@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jann Horn [Fri, 21 Aug 2020 00:42:11 +0000 (17:42 -0700)]
romfs: fix uninitialized memory leak in romfs_dev_read()
romfs has a superblock field that limits the size of the filesystem; data
beyond that limit is never accessed.
romfs_dev_read() fetches a caller-supplied number of bytes from the
backing device. It returns 0 on success or an error code on failure;
therefore, its API can't represent short reads, it's all-or-nothing.
However, when romfs_dev_read() detects that the requested operation would
cross the filesystem size limit, it currently silently truncates the
requested number of bytes. This e.g. means that when the content of a
file with size 0x1000 starts one byte before the filesystem size limit,
->readpage() will only fill a single byte of the supplied page while
leaving the rest uninitialized, leaking that uninitialized memory to
userspace.
Fix it by returning an error code instead of truncating the read when the
requested read operation would go beyond the end of the filesystem.
Fixes: da4458bda237 ("NOMMU: Make it possible for RomFS to use MTD devices directly") Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: David Howells <dhowells@redhat.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200818013202.2246365-1-jannh@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Like zap_pte_range add cond_resched so that we can avoid softlockups as
reported below. On non-preemptible kernel with large I/O map region (like
the one we get when using persistent memory with sector mode), an unmap of
the namespace can report below softlockups.
Hugh Dickins [Fri, 21 Aug 2020 00:42:02 +0000 (17:42 -0700)]
khugepaged: adjust VM_BUG_ON_MM() in __khugepaged_enter()
syzbot crashes on the VM_BUG_ON_MM(khugepaged_test_exit(mm), mm) in
__khugepaged_enter(): yes, when one thread is about to dump core, has set
core_state, and is waiting for others, another might do something calling
__khugepaged_enter(), which now crashes because I lumped the core_state
test (known as "mmget_still_valid") into khugepaged_test_exit(). I still
think it's best to lump them together, so just in this exceptional case,
check mm->mm_users directly instead of khugepaged_test_exit().
Fixes: bbe98f9cadff ("khugepaged: khugepaged_test_exit() check mmget_still_valid()") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Yang Shi <shy828301@gmail.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Song Liu <songliubraving@fb.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Eric Dumazet <edumazet@google.com> Cc: <stable@vger.kernel.org> [4.8+] Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008141503370.18085@eggly.anvils Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Thomas Gleixner [Wed, 19 Aug 2020 19:44:39 +0000 (21:44 +0200)]
core/entry: Respect syscall number rewrites
The transcript of the x86 entry code to the generic version failed to
reload the syscall number from ptregs after ptrace and seccomp have run,
which both can modify the syscall number in ptregs. It returns the original
syscall number instead which is obviously not the right thing to do.
x86/entry/64: Do not use RDPID in paranoid entry to accomodate KVM
KVM has an optmization to avoid expensive MRS read/writes on
VMENTER/EXIT. It caches the MSR values and restores them either when
leaving the run loop, on preemption or when going out to user space.
The affected MSRs are not required for kernel context operations. This
changed with the recently introduced mechanism to handle FSGSBASE in the
paranoid entry code which has to retrieve the kernel GSBASE value by
accessing per CPU memory. The mechanism needs to retrieve the CPU number
and uses either LSL or RDPID if the processor supports it.
Unfortunately RDPID uses MSR_TSC_AUX which is in the list of cached and
lazily restored MSRs, which means between the point where the guest value
is written and the point of restore, MSR_TSC_AUX contains a random number.
If an NMI or any other exception which uses the paranoid entry path happens
in such a context, then RDPID returns the random guest MSR_TSC_AUX value.
As a consequence this reads from the wrong memory location to retrieve the
kernel GSBASE value. Kernel GS is used to for all regular this_cpu_*()
operations. If the GSBASE in the exception handler points to the per CPU
memory of a different CPU then this has the obvious consequences of data
corruption and crashes.
As the paranoid entry path is the only place which accesses MSR_TSX_AUX
(via RDPID) and the fallback via LSL is not significantly slower, remove
the RDPID alternative from the entry path and always use LSL.
The alternative would be to write MSR_TSC_AUX on every VMENTER and VMEXIT
which would be inflicting massive overhead on that code path.
[ tglx: Rewrote changelog ]
Fixes: eaad981291ee3 ("x86/entry/64: Introduce the FIND_PERCPU_BASE macro") Reported-by: Tom Lendacky <thomas.lendacky@amd.com> Debugged-by: Tom Lendacky <thomas.lendacky@amd.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20200821105229.18938-1-pbonzini@redhat.com
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