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2017-10-12iommu/iova: Make rcache flush optional on IOVA allocation failureTomasz Nowicki1-2/+3
Since IOVA allocation failure is not unusual case we need to flush CPUs' rcache in hope we will succeed in next round. However, it is useful to decide whether we need rcache flush step because of two reasons: - Not scalability. On large system with ~100 CPUs iterating and flushing rcache for each CPU becomes serious bottleneck so we may want to defer it. - free_cpu_cached_iovas() does not care about max PFN we are interested in. Thus we may flush our rcaches and still get no new IOVA like in the commonly used scenario: if (dma_limit > DMA_BIT_MASK(32) && dev_is_pci(dev)) iova = alloc_iova_fast(iovad, iova_len, DMA_BIT_MASK(32) >> shift); if (!iova) iova = alloc_iova_fast(iovad, iova_len, dma_limit >> shift); 1. First alloc_iova_fast() call is limited to DMA_BIT_MASK(32) to get PCI devices a SAC address 2. alloc_iova() fails due to full 32-bit space 3. rcaches contain PFNs out of 32-bit space so free_cpu_cached_iovas() throws entries away for nothing and alloc_iova() fails again 4. Next alloc_iova_fast() call cannot take advantage of rcache since we have just defeated caches. In this case we pick the slowest option to proceed. This patch reworks flushed_rcache local flag to be additional function argument instead and control rcache flush step. Also, it updates all users to do the flush as the last chance. Signed-off-by: Tomasz Nowicki <Tomasz.Nowicki@caviumnetworks.com> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Tested-by: Nate Watterson <nwatters@codeaurora.org> Signed-off-by: Joerg Roedel <jroedel@suse.de>
2017-09-27iommu/iova: Add rbtree anchor nodeRobin Murphy1-0/+1
Add a permanent dummy IOVA reservation to the rbtree, such that we can always access the top of the address space instantly. The immediate benefit is that we remove the overhead of the rb_last() traversal when not using the cached node, but it also paves the way for further simplifications. Signed-off-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
2017-09-27iommu/iova: Make dma_32bit_pfn implicitZhen Lei1-3/+2
Now that the cached node optimisation can apply to all allocations, the couple of users which were playing tricks with dma_32bit_pfn in order to benefit from it can stop doing so. Conversely, there is also no need for all the other users to explicitly calculate a 'real' 32-bit PFN, when init_iova_domain() can happily do that itself from the page granularity. CC: Thierry Reding <thierry.reding@gmail.com> CC: Jonathan Hunter <jonathanh@nvidia.com> CC: David Airlie <airlied@linux.ie> CC: Sudeep Dutt <sudeep.dutt@intel.com> CC: Ashutosh Dixit <ashutosh.dixit@intel.com> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Zhen Lei <thunder.leizhen@huawei.com> Tested-by: Nate Watterson <nwatters@codeaurora.org> [rm: use iova_shift(), rewrote commit message] Signed-off-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
2017-09-27iommu/iova: Extend rbtree node cachingRobin Murphy1-1/+2
The cached node mechanism provides a significant performance benefit for allocations using a 32-bit DMA mask, but in the case of non-PCI devices or where the 32-bit space is full, the loss of this benefit can be significant - on large systems there can be many thousands of entries in the tree, such that walking all the way down to find free space every time becomes increasingly awful. Maintain a similar cached node for the whole IOVA space as a superset of the 32-bit space so that performance can remain much more consistent. Inspired by work by Zhen Lei <thunder.leizhen@huawei.com>. Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Zhen Lei <thunder.leizhen@huawei.com> Tested-by: Nate Watterson <nwatters@codeaurora.org> Signed-off-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
2017-08-15iommu/iova: Add flush timerJoerg Roedel1-0/+8
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>
2017-08-15iommu/iova: Add locking to Flush-QueuesJoerg Roedel1-0/+1
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>
2017-08-15iommu/iova: Add flush counters to Flush-Queue implementationJoerg Roedel1-0/+8
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>
2017-08-15iommu/iova: Implement Flush-Queue ring bufferJoerg Roedel1-0/+9
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>
2017-08-15iommu/iova: Add flush-queue data structuresJoerg Roedel1-0/+41
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>
2017-03-23iommu/iova: Fix compile error with CONFIG_IOMMU_IOVA=mJoerg Roedel1-1/+1
The #ifdef in iova.h only catches the CONFIG_IOMMU_IOVA=y case, so that compilation as a module fails with duplicate function definition errors. Fix it by catching both cases in the #if. Signed-off-by: Joerg Roedel <jroedel@suse.de>
2017-03-22iommu: Add dummy implementations for !IOMMU_IOVAThierry Reding1-0/+91
Currently, building code which uses the API guarded by the IOMMU_IOVA will fail to link if IOMMU_IOVA is not enabled. Often this code will be using the API provided by the IOMMU_API Kconfig symbol, but support for this can be optional, with code falling back to contiguous memory. This commit implements dummy functions for the IOVA API so that it can be compiled out. With both IOMMU_API and IOMMU_IOVA optional, code can now be built with or without support for IOMMU without having to resort to #ifdefs in the user code. Signed-off-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
2016-04-20iommu/iova: introduce per-cpu caching to iova allocationOmer Peleg1-2/+21
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>
2015-07-28iommu: iova: Move iova cache management to the iova librarySakari Ailus1-2/+2
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>
2015-01-19iommu: Make IOVA domain page size explicitRobin Murphy1-2/+33
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>
2015-01-19iommu: Make IOVA domain low limit flexibleRobin Murphy1-4/+3
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>
2015-01-19iommu: Consolidate IOVA allocator codeRobin Murphy1-0/+3
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>
2014-07-23iommu/vt-d: Introduce helper function iova_size() to improve code readabilityJiang Liu1-0/+5
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
2014-03-04iommu/vt-d: Update IOMMU state when memory hotplug happensJiang Liu1-0/+2
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>
2009-07-15intel-iommu: Remove superfluous iova_alloc_lock from IOVA codeDavid Woodhouse1-1/+0
We only ever obtain this lock immediately before the iova_rbtree_lock, and release it immediately after the iova_rbtree_lock. So ditch it and just use iova_rbtree_lock. [v2: Remove the lockdep bits this time too] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-10-15VT-d: Changes to support KVMKay, Allen M1-0/+52
This patch extends the VT-d driver to support KVM [Ben: fixed memory pinning] [avi: move dma_remapping.h as well] Signed-off-by: Kay, Allen M <allen.m.kay@intel.com> Signed-off-by: Weidong Han <weidong.han@intel.com> Signed-off-by: Ben-Ami Yassour <benami@il.ibm.com> Signed-off-by: Amit Shah <amit.shah@qumranet.com> Acked-by: Mark Gross <mgross@linux.intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>