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[ Upstream commit 0d87308cca2c124f9bce02383f1d9632c9be89c4 ]
In commit 14bd9a607f90 ("iommu/iova: Separate atomic variables
to improve performance") Jinyu Qi identified that the atomic_cmpxchg()
in queue_iova() was causing a performance loss and moved critical fields
so that the false sharing would not impact them.
However, avoiding the false sharing in the first place seems easy.
We should attempt the atomic_cmpxchg() no more than 100 times
per second. Adding an atomic_read() will keep the cache
line mostly shared.
This false sharing came with commit 9a005a800ae8
("iommu/iova: Add flush timer").
Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 9a005a800ae8 ('iommu/iova: Add flush timer')
Cc: Jinyu Qi <jinyuqi@huawei.com>
Cc: Joerg Roedel <jroedel@suse.de>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit effa467870c7612012885df4e246bdb8ffd8e44c upstream.
Intel VT-d driver was reworked to use common deferred flushing
implementation. Previously there was one global per-cpu flush queue,
afterwards - one per domain.
Before deferring a flush, the queue should be allocated and initialized.
Currently only domains with IOMMU_DOMAIN_DMA type initialize their flush
queue. It's probably worth to init it for static or unmanaged domains
too, but it may be arguable - I'm leaving it to iommu folks.
Prevent queuing an iova flush if the domain doesn't have a queue.
The defensive check seems to be worth to keep even if queue would be
initialized for all kinds of domains. And is easy backportable.
On 4.19.43 stable kernel it has a user-visible effect: previously for
devices in si domain there were crashes, on sata devices:
BUG: spinlock bad magic on CPU#6, swapper/0/1
lock: 0xffff88844f582008, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
CPU: 6 PID: 1 Comm: swapper/0 Not tainted 4.19.43 #1
Call Trace:
<IRQ>
dump_stack+0x61/0x7e
spin_bug+0x9d/0xa3
do_raw_spin_lock+0x22/0x8e
_raw_spin_lock_irqsave+0x32/0x3a
queue_iova+0x45/0x115
intel_unmap+0x107/0x113
intel_unmap_sg+0x6b/0x76
__ata_qc_complete+0x7f/0x103
ata_qc_complete+0x9b/0x26a
ata_qc_complete_multiple+0xd0/0xe3
ahci_handle_port_interrupt+0x3ee/0x48a
ahci_handle_port_intr+0x73/0xa9
ahci_single_level_irq_intr+0x40/0x60
__handle_irq_event_percpu+0x7f/0x19a
handle_irq_event_percpu+0x32/0x72
handle_irq_event+0x38/0x56
handle_edge_irq+0x102/0x121
handle_irq+0x147/0x15c
do_IRQ+0x66/0xf2
common_interrupt+0xf/0xf
RIP: 0010:__do_softirq+0x8c/0x2df
The same for usb devices that use ehci-pci:
BUG: spinlock bad magic on CPU#0, swapper/0/1
lock: 0xffff88844f402008, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.43 #4
Call Trace:
<IRQ>
dump_stack+0x61/0x7e
spin_bug+0x9d/0xa3
do_raw_spin_lock+0x22/0x8e
_raw_spin_lock_irqsave+0x32/0x3a
queue_iova+0x77/0x145
intel_unmap+0x107/0x113
intel_unmap_page+0xe/0x10
usb_hcd_unmap_urb_setup_for_dma+0x53/0x9d
usb_hcd_unmap_urb_for_dma+0x17/0x100
unmap_urb_for_dma+0x22/0x24
__usb_hcd_giveback_urb+0x51/0xc3
usb_giveback_urb_bh+0x97/0xde
tasklet_action_common.isra.4+0x5f/0xa1
tasklet_action+0x2d/0x30
__do_softirq+0x138/0x2df
irq_exit+0x7d/0x8b
smp_apic_timer_interrupt+0x10f/0x151
apic_timer_interrupt+0xf/0x20
</IRQ>
RIP: 0010:_raw_spin_unlock_irqrestore+0x17/0x39
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: <stable@vger.kernel.org> # 4.14+
Fixes: 13cf01744608 ("iommu/vt-d: Make use of iova deferred flushing")
Signed-off-by: Dmitry Safonov <dima@arista.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
[v4.14-port notes:
o minor conflict with untrusted IOMMU devices check under if-condition
o setup_timer() near one chunk is timer_setup() in v5.3]
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add a timer to flush entries from the Flush-Queues every
10ms. This makes sure that no stale TLB entries remain for
too long after an IOVA has been unmapped.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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The lock is taken from the same CPU most of the time. But
having it allows to flush the queue also from another CPU if
necessary.
This will be used by a timer to regularily flush any pending
IOVAs from the Flush-Queues.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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There are two counters:
* fq_flush_start_cnt - Increased when a TLB flush
is started.
* fq_flush_finish_cnt - Increased when a TLB flush
is finished.
The fq_flush_start_cnt is assigned to every Flush-Queue
entry on its creation. When freeing entries from the
Flush-Queue, the value in the entry is compared to the
fq_flush_finish_cnt. The entry can only be freed when its
value is less than the value of fq_flush_finish_cnt.
The reason for these counters it to take advantage of IOMMU
TLB flushes that happened on other CPUs. These already
flushed the TLB for Flush-Queue entries on other CPUs so
that they can already be freed without flushing the TLB
again.
This makes it less likely that the Flush-Queue is full and
saves IOMMU TLB flushes.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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Add a function to add entries to the Flush-Queue ring
buffer. If the buffer is full, call the flush-callback and
free the entries.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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This patch adds the basic data-structures to implement
flush-queues in the generic IOVA code. It also adds the
initialization and destroy routines for these data
structures.
The initialization routine is designed so that the use of
this feature is optional for the users of IOVA code.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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'arm/core', 'x86/vt-d', 'x86/amd', 's390' and 'core' into next
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Commit 583248e6620a ("iommu/iova: Disable preemption around use of
this_cpu_ptr()") disables preemption while accessing a per-CPU variable.
This does keep lockdep quiet. However I don't see the point why it is
bad if we get migrated after its access to another CPU.
__iova_rcache_insert() and __iova_rcache_get() immediately locks the
variable after obtaining it - before accessing its members.
_If_ we get migrated away after retrieving the address of cpu_rcache
before taking the lock then the *other* task on the same CPU will
retrieve the same address of cpu_rcache and will spin on the lock.
alloc_iova_fast() disables preemption while invoking
free_cpu_cached_iovas() on each CPU. The function itself uses
per_cpu_ptr() which does not trigger a warning (like this_cpu_ptr()
does). It _could_ make sense to use get_online_cpus() instead but the we
have a hotplug notifier for CPU down (and none for up) so we are good.
Cc: Joerg Roedel <joro@8bytes.org>
Cc: iommu@lists.linux-foundation.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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When walking the rbtree, the fact that iovad->start_pfn and limit_pfn
are both inclusive limits creates an ambiguity once limit_pfn reaches
the bottom of the address space and they overlap. Commit 5016bdb796b3
("iommu/iova: Fix underflow bug in __alloc_and_insert_iova_range") fixed
the worst side-effect of this, that of underflow wraparound leading to
bogus allocations, but the remaining fallout is that any attempt to
allocate start_pfn itself erroneously fails.
The cleanest way to resolve the ambiguity is to simply make limit_pfn an
exclusive limit when inside the guts of the rbtree. Since we're working
with PFNs, representing one past the top of the address space is always
possible without fear of overflow, and elsewhere it just makes life a
little more straightforward.
Reported-by: Aaron Sierra <asierra@xes-inc.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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'arm/smmu', 'arm/core', 'x86/vt-d', 'x86/amd' and 'core' into next
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Normally, calling alloc_iova() using an iova_domain with insufficient
pfns remaining between start_pfn and dma_limit will fail and return a
NULL pointer. Unexpectedly, if such a "full" iova_domain contains an
iova with pfn_lo == 0, the alloc_iova() call will instead succeed and
return an iova containing invalid pfns.
This is caused by an underflow bug in __alloc_and_insert_iova_range()
that occurs after walking the "full" iova tree when the search ends
at the iova with pfn_lo == 0 and limit_pfn is then adjusted to be just
below that (-1). This (now huge) limit_pfn gives the impression that a
vast amount of space is available between it and start_pfn and thus
a new iova is allocated with the invalid pfn_hi value, 0xFFF.... .
To rememdy this, a check is introduced to ensure that adjustments to
limit_pfn will not underflow.
This issue has been observed in the wild, and is easily reproduced with
the following sample code.
struct iova_domain *iovad = kzalloc(sizeof(*iovad), GFP_KERNEL);
struct iova *rsvd_iova, *good_iova, *bad_iova;
unsigned long limit_pfn = 3;
unsigned long start_pfn = 1;
unsigned long va_size = 2;
init_iova_domain(iovad, SZ_4K, start_pfn, limit_pfn);
rsvd_iova = reserve_iova(iovad, 0, 0);
good_iova = alloc_iova(iovad, va_size, limit_pfn, true);
bad_iova = alloc_iova(iovad, va_size, limit_pfn, true);
Prior to the patch, this yielded:
*rsvd_iova == {0, 0} /* Expected */
*good_iova == {2, 3} /* Expected */
*bad_iova == {-2, -1} /* Oh no... */
After the patch, bad_iova is NULL as expected since inadequate
space remains between limit_pfn and start_pfn after allocating
good_iova.
Signed-off-by: Nate Watterson <nwatters@codeaurora.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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This patch consolidates almost the same code used in iova_insert_rbtree()
and __alloc_and_insert_iova_range() functions. While touching this code,
replace BUG() with WARN_ON(1) to avoid taking down the whole system in
case of corrupted iova tree or incorrect calls.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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To make the code clearer, use rb_entry() instead of container_of() to
deal with rbtree.
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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When searching for a free IOVA range, we optimise the tree traversal
by starting from the cached32_node, instead of the last node, when
limit_pfn is equal to dma_32bit_pfn. However, if limit_pfn happens to
be smaller, then we'll go ahead and start from the top even though
dma_32bit_pfn is still a more suitable upper bound. Since this is
clearly a silly thing to do, adjust the lookup condition appropriately.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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Between acquiring the this_cpu_ptr() and using it, ideally we don't want
to be preempted and work on another CPU's private data. this_cpu_ptr()
checks whether or not preemption is disable, and get_cpu_ptr() provides
a convenient wrapper for operating on the cpu ptr inside a preemption
disabled critical section (which currently is provided by the
spinlock).
[ 167.997877] BUG: using smp_processor_id() in preemptible [00000000] code: usb-storage/216
[ 167.997940] caller is debug_smp_processor_id+0x17/0x20
[ 167.997945] CPU: 7 PID: 216 Comm: usb-storage Tainted: G U 4.7.0-rc1-gfxbench-RO_Patchwork_1057+ #1
[ 167.997948] Hardware name: Hewlett-Packard HP Pro 3500 Series/2ABF, BIOS 8.11 10/24/2012
[ 167.997951] 0000000000000000 ffff880118b7f9c8 ffffffff8140dca5 0000000000000007
[ 167.997958] ffffffff81a3a7e9 ffff880118b7f9f8 ffffffff8142a927 0000000000000000
[ 167.997965] ffff8800d499ed58 0000000000000001 00000000000fffff ffff880118b7fa08
[ 167.997971] Call Trace:
[ 167.997977] [<ffffffff8140dca5>] dump_stack+0x67/0x92
[ 167.997981] [<ffffffff8142a927>] check_preemption_disabled+0xd7/0xe0
[ 167.997985] [<ffffffff8142a947>] debug_smp_processor_id+0x17/0x20
[ 167.997990] [<ffffffff81507e17>] alloc_iova_fast+0xb7/0x210
[ 167.997994] [<ffffffff8150c55f>] intel_alloc_iova+0x7f/0xd0
[ 167.997998] [<ffffffff8151021d>] intel_map_sg+0xbd/0x240
[ 167.998002] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20
[ 167.998009] [<ffffffff81596059>] usb_hcd_map_urb_for_dma+0x4b9/0x5a0
[ 167.998013] [<ffffffff81596d19>] usb_hcd_submit_urb+0xe9/0xaa0
[ 167.998017] [<ffffffff810cff2f>] ? mark_held_locks+0x6f/0xa0
[ 167.998022] [<ffffffff810d525c>] ? __raw_spin_lock_init+0x1c/0x50
[ 167.998025] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20
[ 167.998028] [<ffffffff815988f3>] usb_submit_urb+0x3f3/0x5a0
[ 167.998032] [<ffffffff810d0082>] ? trace_hardirqs_on_caller+0x122/0x1b0
[ 167.998035] [<ffffffff81599ae7>] usb_sg_wait+0x67/0x150
[ 167.998039] [<ffffffff815dc202>] usb_stor_bulk_transfer_sglist.part.3+0x82/0xd0
[ 167.998042] [<ffffffff815dc29c>] usb_stor_bulk_srb+0x4c/0x60
[ 167.998045] [<ffffffff815dc42e>] usb_stor_Bulk_transport+0x17e/0x420
[ 167.998049] [<ffffffff815dcf32>] usb_stor_invoke_transport+0x242/0x540
[ 167.998052] [<ffffffff810e5efd>] ? debug_lockdep_rcu_enabled+0x1d/0x20
[ 167.998058] [<ffffffff815dba19>] usb_stor_transparent_scsi_command+0x9/0x10
[ 167.998061] [<ffffffff815de518>] usb_stor_control_thread+0x158/0x260
[ 167.998064] [<ffffffff815de3c0>] ? fill_inquiry_response+0x20/0x20
[ 167.998067] [<ffffffff815de3c0>] ? fill_inquiry_response+0x20/0x20
[ 167.998071] [<ffffffff8109ddfa>] kthread+0xea/0x100
[ 167.998078] [<ffffffff817ac6af>] ret_from_fork+0x1f/0x40
[ 167.998081] [<ffffffff8109dd10>] ? kthread_create_on_node+0x1f0/0x1f0
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96293
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: iommu@lists.linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Fixes: 9257b4a206fc ('iommu/iova: introduce per-cpu caching to iova allocation')
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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IOVA allocation has two problems that impede high-throughput I/O.
First, it can do a linear search over the allocated IOVA ranges.
Second, the rbtree spinlock that serializes IOVA allocations becomes
contended.
Address these problems by creating an API for caching allocated IOVA
ranges, so that the IOVA allocator isn't accessed frequently. This
patch adds a per-CPU cache, from which CPUs can alloc/free IOVAs
without taking the rbtree spinlock. The per-CPU caches are backed by
a global cache, to avoid invoking the (linear-time) IOVA allocator
without needing to make the per-CPU cache size excessive. This design
is based on magazines, as described in "Magazines and Vmem: Extending
the Slab Allocator to Many CPUs and Arbitrary Resources" (currently
available at https://www.usenix.org/legacy/event/usenix01/bonwick.html)
Adding caching on top of the existing rbtree allocator maintains the
property that IOVAs are densely packed in the IO virtual address space,
which is important for keeping IOMMU page table usage low.
To keep the cache size reasonable, we bound the IOVA space a CPU can
cache by 32 MiB (we cache a bounded number of IOVA ranges, and only
ranges of size <= 128 KiB). The shared global cache is bounded at
4 MiB of IOVA space.
Signed-off-by: Omer Peleg <omer@cs.technion.ac.il>
[mad@cs.technion.ac.il: rebased, cleaned up and reworded the commit message]
Signed-off-by: Adam Morrison <mad@cs.technion.ac.il>
Reviewed-by: Shaohua Li <shli@fb.com>
Reviewed-by: Ben Serebrin <serebrin@google.com>
[dwmw2: split out VT-d part into a separate patch]
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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The iova library has use outside the intel-iommu driver, thus make it a
module.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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Use EXPORT_SYMBOL_GPL() to export the iova library symbols. The symbols
include:
init_iova_domain();
iova_cache_get();
iova_cache_put();
iova_cache_init();
alloc_iova();
find_iova();
__free_iova();
free_iova();
put_iova_domain();
reserve_iova();
copy_reserved_iova();
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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This is necessary to separate intel-iommu from the iova library.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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Currently, allocating a size-aligned IOVA region quietly adjusts the
actual allocation size in the process, returning a rounded-up
power-of-two-sized allocation. This results in mismatched behaviour in
the IOMMU driver if the original size was not a power of two, where the
original size is mapped, but the rounded-up IOVA size is unmapped.
Whilst some IOMMUs will happily unmap already-unmapped pages, others
consider this an error, so fix it by computing the necessary alignment
padding without altering the actual allocation size. Also clean up by
making pad_size unsigned, since its callers always pass unsigned values
and negative padding makes little sense here anyway.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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Fixed checkpatch warnings for missing blank line after
declaration of struct.
Signed-off-by: Robert Callicotte <rcallicotte@gmail.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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Systems may contain heterogeneous IOMMUs supporting differing minimum
page sizes, which may also not be common with the CPU page size.
Thus it is practical to have an explicit notion of IOVA granularity
to simplify handling of mapping and allocation constraints.
As an initial step, move the IOVA page granularity from an implicit
compile-time constant to a per-domain property so we can make use
of it in IOVA domain context at runtime. To keep the abstraction tidy,
extend the little API of inline iova_* helpers to parallel some of the
equivalent PAGE_* macros.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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To share the IOVA allocator with other architectures, it needs to
accommodate more general aperture restrictions; move the lower limit
from a compile-time constant to a runtime domain property to allow
IOVA domains with different requirements to co-exist.
Also reword the slightly unclear description of alloc_iova since we're
touching it anyway.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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In order to share the IOVA allocator with other architectures, break
the unnecssary dependency on the Intel IOMMU driver and move the
remaining IOVA internals to iova.c
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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If static identity domain is created, IOMMU driver needs to update
si_domain page table when memory hotplug event happens. Otherwise
PCI device DMA operations can't access the hot-added memory regions.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>
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Correct spelling typo in debug messages and comments
in drivers/iommu.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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This should ease finding similarities with different platforms,
with the intention of solving problems once in a generic framework
which everyone can use.
Note: to move intel-iommu.c, the declaration of pci_find_upstream_pcie_bridge()
has to move from drivers/pci/pci.h to include/linux/pci.h. This is handled
in this patch, too.
As suggested, also drop DMAR's EXPERIMENTAL tag while we're at it.
Compile-tested on x86_64.
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
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