Messages in this thread | | | Subject | Re: [PATCH v2] vfio iommu: Add dma available capability | From | Matthew Rosato <> | Date | Tue, 15 Sep 2020 09:22:13 -0400 |
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On 9/15/20 5:44 AM, Cornelia Huck wrote: > On Mon, 14 Sep 2020 18:25:31 -0400 > Matthew Rosato <mjrosato@linux.ibm.com> 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 mappings. Let's provide the current allowable >> number of DMA mappings to userspace via the IOMMU info chain so that >> userspace can take appropriate mitigation. >> >> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> >> --- >> drivers/vfio/vfio_iommu_type1.c | 17 +++++++++++++++++ >> include/uapi/linux/vfio.h | 16 ++++++++++++++++ >> 2 files changed, 33 insertions(+) > > (...) > >> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h >> index 9204705..a8cc4a5 100644 >> --- a/include/uapi/linux/vfio.h >> +++ b/include/uapi/linux/vfio.h >> @@ -1039,6 +1039,22 @@ struct vfio_iommu_type1_info_cap_migration { >> __u64 max_dirty_bitmap_size; /* in bytes */ >> }; >> >> +/* >> + * The DMA available capability allows to report the current number of >> + * simultaneously outstanding DMA mappings that are allowed. >> + * >> + * The structures below define version 1 of this capability. > > "The structure below defines..." ? >
OK
>> + * >> + * max: specifies the maximum number of outstanding DMA mappings allowed. > > I think you forgot to tweak that one: > > "avail: specifies the current number of outstanding DMA mappings allowed." > > ?
Yep, that's a leftover from v1 :(
> >> + */ >> +#define VFIO_IOMMU_TYPE1_INFO_DMA_AVAIL 3 >> + >> +struct vfio_iommu_type1_info_dma_avail { >> + struct vfio_info_cap_header header; >> + __u32 avail; >> +}; >> + >> + >> #define VFIO_IOMMU_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12) >> >> /** >
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