kernel/linux.git/include/linux/swiotlb.h, branch v6.4-rc6

Merge tag 'dma-mapping-6.4-2023-04-28' of git://git.infradead.org/users/hch/dma-mapping

2023-04-29T17:29:57+00:00

Pull dma-mapping updates from Christoph Hellwig: - fix a PageHighMem check in dma-coherent initialization (Doug Berger) - clean up the coherency defaul initialiation (Jiaxun Yang) - add cacheline to user/kernel dma-debug space dump messages (Desnes Nunes, Geert Uytterhoeve) - swiotlb statistics improvements (Michael Kelley) - misc cleanups (Petr Tesarik) * tag 'dma-mapping-6.4-2023-04-28' of git://git.infradead.org/users/hch/dma-mapping: swiotlb: Omit total_used and used_hiwater if !CONFIG_DEBUG_FS swiotlb: track and report io_tlb_used high water marks in debugfs swiotlb: fix debugfs reporting of reserved memory pools swiotlb: relocate PageHighMem test away from rmem_swiotlb_setup of: address: always use dma_default_coherent for default coherency dma-mapping: provide CONFIG_ARCH_DMA_DEFAULT_COHERENT dma-mapping: provide a fallback dma_default_coherent dma-debug: Use %pa to format phys_addr_t dma-debug: add cacheline to user/kernel space dump messages dma-debug: small dma_debug_entry's comment and variable name updates dma-direct: cleanup parameters to dma_direct_optimal_gfp_mask

swiotlb: Omit total_used and used_hiwater if !CONFIG_DEBUG_FS

2023-04-20T12:51:41+00:00

The tracking of used_hiwater adds an atomic operation to the hot path. This is acceptable only when debugging the kernel. To make sure that the fields can never be used by mistake, do not even include them in struct io_tlb_mem if CONFIG_DEBUG_FS is not set. The build fails after doing that. To fix it, it is necessary to remove all code specific to debugfs and instead provide a stub implementation of swiotlb_create_debugfs_files(). As a bonus, this change allows to remove one __maybe_unused attribute. Signed-off-by: Petr Tesarik Signed-off-by: Christoph Hellwig

swiotlb: Remove bounce buffer remapping for Hyper-V

2023-04-17T19:19:04+00:00

With changes to how Hyper-V guest VMs flip memory between private (encrypted) and shared (decrypted), creating a second kernel virtual mapping for shared memory is no longer necessary. Everything needed for the transition to shared is handled by set_memory_decrypted(). As such, remove swiotlb_unencrypted_base and the associated code. Signed-off-by: Michael Kelley Acked-by: Christoph Hellwig Acked-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/1679838727-87310-8-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu

swiotlb: track and report io_tlb_used high water marks in debugfs

2023-04-16T06:25:29+00:00

swiotlb currently reports the total number of slabs and the instantaneous in-use slabs in debugfs. But with increased usage of swiotlb for all I/O in Confidential Computing (coco) VMs, it has become difficult to know how much memory to allocate for swiotlb bounce buffers, either via the automatic algorithm in the kernel or by specifying a value on the kernel boot line. The current automatic algorithm generously allocates swiotlb bounce buffer memory, and may be wasting significant memory in many use cases. To support better understanding of swiotlb usage, add tracking of the the high water mark for usage of the default swiotlb bounce buffer memory pool and any reserved memory pools. Report these high water marks in debugfs along with the other swiotlb pool metrics. Allow the high water marks to be reset to zero at runtime by writing to them. Signed-off-by: Michael Kelley Signed-off-by: Christoph Hellwig

swiotlb: remove swiotlb_max_segment

2023-02-16T17:10:18+00:00

swiotlb_max_segment has always been a bogus API, so remove it now that the remaining callers are gone. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

swiotlb: move struct io_tlb_slot to swiotlb.c

2022-07-18T04:50:18+00:00

No need to expose this structure definition in the header. Signed-off-by: Christoph Hellwig

swiotlb: remove unused fields in io_tlb_mem

2022-07-18T04:48:54+00:00

Commit 20347fca71a3 ("swiotlb: split up the global swiotlb lock") splits io_tlb_mem into multiple areas. Each area has its own lock and index. The global ones are not used so remove them. Signed-off-by: Chao Gao Signed-off-by: Christoph Hellwig

swiotlb: split up the global swiotlb lock

2022-07-13T11:23:10+00:00

Traditionally swiotlb was not performance critical because it was only used for slow devices. But in some setups, like TDX/SEV confidential guests, all IO has to go through swiotlb. Currently swiotlb only has a single lock. Under high IO load with multiple CPUs this can lead to significat lock contention on the swiotlb lock. This patch splits the swiotlb bounce buffer pool into individual areas which have their own lock. Each CPU tries to allocate in its own area first. Only if that fails does it search other areas. On freeing the allocation is freed into the area where the memory was originally allocated from. Area number can be set via swiotlb kernel parameter and is default to be possible cpu number. If possible cpu number is not power of 2, area number will be round up to the next power of 2. This idea from Andi Kleen patch(https://github.com/intel/tdx/commit/ 4529b5784c141782c72ec9bd9a92df2b68cb7d45). Based-on-idea-by: Andi Kleen Signed-off-by: Tianyu Lan Signed-off-by: Christoph Hellwig

swiotlb: remove the unused swiotlb_force declaration

2022-06-22T10:41:45+00:00

The 'swiotlb_force' is removed since commit c6af2aa9ffc9 ("swiotlb: make the swiotlb_init interface more useful"). Signed-off-by: Dongli Zhang Signed-off-by: Christoph Hellwig

swiotlb: remove swiotlb_init_with_tbl and swiotlb_init_late_with_tbl

2022-04-18T05:21:14+00:00

No users left. Signed-off-by: Christoph Hellwig Reviewed-by: Konrad Rzeszutek Wilk Tested-by: Boris Ostrovsky