Re: [PATCH v3] vfio iommu: Add dma available capability

2020-09-16 Thread Cornelia Huck
On Tue, 15 Sep 2020 15:05:18 -0400 Matthew Rosato wrote: > Commit 492855939bdb ("vfio/type1: Limit DMA mappings per container") > added the ability to limit the number of memory backed DMA mappings. > However on s390x, when lazy mapping is in use, we use a very large > number of concurrent mappin

Re: [PATCH v3] vfio iommu: Add dma available capability

2020-09-15 Thread Matthew Rosato
On 9/15/20 3:05 PM, Matthew Rosato wrote: Commit 492855939bdb ("vfio/type1: Limit DMA mappings per container") added a limit to the number of concurrent DMA requests for a vfio container. However, lazy unmapping in s390 can in fact cause quite a large number of outstanding DMA requests to build u

[PATCH v3] vfio iommu: Add dma available capability

2020-09-15 Thread Matthew Rosato
Commit 492855939bdb ("vfio/type1: Limit DMA mappings per container") added the ability to limit the number of memory backed DMA mappings. However on s390x, when lazy mapping is in use, we use a very large number of concurrent mappings. Let's provide the current allowable number of DMA mappings to

[PATCH v3] vfio iommu: Add dma available capability

2020-09-15 Thread Matthew Rosato
Commit 492855939bdb ("vfio/type1: Limit DMA mappings per container") added a limit to the number of concurrent DMA requests for a vfio container. However, lazy unmapping in s390 can in fact cause quite a large number of outstanding DMA requests to build up prior to being purged, potentially the en