Messages in this thread | | | Date | Tue, 22 Feb 2022 23:07:19 +0800 | Subject | Re: [PATCH V2 1/2] Swiotlb: Add swiotlb_alloc_from_low_pages switch | From | Tianyu Lan <> |
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On 2/22/2022 4:05 PM, Christoph Hellwig wrote: > On Mon, Feb 21, 2022 at 11:14:58PM +0800, Tianyu Lan wrote: >> Sorry. The boot failure is not related with these patches and the issue >> has been fixed in the latest upstream code. >> >> There is a performance bottleneck due to io tlb mem's spin lock during >> performance test. All devices'io queues uses same io tlb mem entry >> and the spin lock of io tlb mem introduce overheads. There is a fix patch >> from Andi Kleen in the github. Could you have a look? >> >> https://github.com/intel/tdx/commit/4529b5784c141782c72ec9bd9a92df2b68cb7d45 > > Please post these things to the list. > > But I suspect the right answer for the "secure" hypervisor case is to > use the per-device swiotlb regions that we've recently added.
Thanks for your comment. That means we need to expose an swiotlb_device_init() interface to allocate bounce buffer and initialize io tlb mem entry. DMA API Current rmem_swiotlb_device_init() only works for platform with device tree. The new API should be called in the bus driver or new DMA API. Could you check whether this is a right way before we start the work.
Thanks.
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