Re: [PATCH] vfio iommu: Add dma limit capability

2020-09-11 Thread Matthew Rosato
On 9/11/20 1:09 PM, Alex Williamson wrote: On Fri, 11 Sep 2020 12:44:03 -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

Re: [PATCH] vfio iommu: Add dma limit capability

2020-09-11 Thread Alex Williamson
On Fri, 11 Sep 2020 12:44:03 -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] vfio iommu: Add dma limit capability

2020-09-11 Thread Matthew Rosato
On 9/11/20 12:44 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

[PATCH] vfio iommu: Add dma limit capability

2020-09-11 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 limitation to userspace via the IOMMU info c

[PATCH] vfio iommu: Add dma limit capability

2020-09-11 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