Messages in this thread | | | Date | Fri, 26 Nov 2021 19:39:03 +0800 | Subject | Re: [PATCH 3/5] hyperv/IOMMU: Enable swiotlb bounce buffer for Isolation VM | From | Tianyu Lan <> |
| |
On 11/26/2021 3:40 PM, Christoph Hellwig wrote: > On Wed, Nov 17, 2021 at 10:00:08PM +0800, Tianyu Lan wrote: >> On 11/17/2021 6:01 PM, Christoph Hellwig wrote: >>> This doesn't really have much to do with normal DMA mapping, >>> so why does this direct through the dma ops? >>> >> >> According to the previous discussion, dma_alloc_noncontigous() >> and dma_vmap_noncontiguous() may be used to handle the noncontigous >> memory alloc/map in the netvsc driver. So add alloc/free and vmap/vunmap >> callbacks here to handle the case. The previous patch v4 & v5 handles >> the allocation and map in the netvsc driver. If this should not go though >> dma ops, We also may make it as vmbus specific function and keep >> the function in the vmbus driver. > > But that only makes sense if they can actually use the normal DMA ops. > If you implement your own incomplete ops and require to use them you > do nothing but adding indirect calls to your fast path and making the > code convoluted. >
Because the generic part implementation can't meet the netvsc driver requests that allocate 16M memory and map pages via vmap_pfn(). So add Hyperv alloc_noncontiguous and vmap_noncontiguous callbacks. If this is not a right way. we should call these hyper-V functions in the netvsc driver directly, right?
Could you have a look at Michael summary about this series we made and give some guides?
https://www.mail-archive.com/xen-devel@lists.xenproject.org/msg109284.html
Thanks.
| |