From 7486a62845b1e12011dd99973e4739f69d57cd38 Mon Sep 17 00:00:00 2001
From: Matthew Rosato <mjrosato@linux.ibm.com>
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 <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
[aw: vfio_get_info_dma_avail moved inside CONFIG_LINUX]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
hw/vfio/common.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
(limited to 'hw')
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)
{
--
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