From 7486a62845b1e12011dd99973e4739f69d57cd38 Mon Sep 17 00:00:00 2001 From: Matthew Rosato Date: Mon, 26 Oct 2020 11:34:33 -0400 Subject: vfio: Find DMA available capability The underlying host may be limiting the number of outstanding DMA requests for type 1 IOMMU. Add helper functions to check for the DMA available capability and retrieve the current number of DMA mappings allowed. Signed-off-by: Matthew Rosato Reviewed-by: Cornelia Huck [aw: vfio_get_info_dma_avail moved inside CONFIG_LINUX] Signed-off-by: Alex Williamson --- hw/vfio/common.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'hw/vfio') diff --git a/hw/vfio/common.c b/hw/vfio/common.c index 693d3a2943..920786a23e 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -1149,6 +1149,37 @@ vfio_get_region_info_cap(struct vfio_region_info *info, uint16_t id) return vfio_get_cap((void *)info, info->cap_offset, id); } +static struct vfio_info_cap_header * +vfio_get_iommu_type1_info_cap(struct vfio_iommu_type1_info *info, uint16_t id) +{ + if (!(info->flags & VFIO_IOMMU_INFO_CAPS)) { + return NULL; + } + + return vfio_get_cap((void *)info, info->cap_offset, id); +} + +bool vfio_get_info_dma_avail(struct vfio_iommu_type1_info *info, + unsigned int *avail) +{ + struct vfio_info_cap_header *hdr; + struct vfio_iommu_type1_info_dma_avail *cap; + + /* If the capability cannot be found, assume no DMA limiting */ + hdr = vfio_get_iommu_type1_info_cap(info, + VFIO_IOMMU_TYPE1_INFO_DMA_AVAIL); + if (hdr == NULL) { + return false; + } + + if (avail != NULL) { + cap = (void *) hdr; + *avail = cap->avail; + } + + return true; +} + static int vfio_setup_region_sparse_mmaps(VFIORegion *region, struct vfio_region_info *info) { -- cgit v1.2.3-55-g7522