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authorMatthew Rosato <mjrosato@linux.ibm.com>2020-09-15 15:05:18 -0400
committerAlex Williamson <alex.williamson@redhat.com>2020-09-21 14:58:34 -0600
commit7d6e1329652ed971d1b6e0e7bea66fba5044e271 (patch)
treecc46122738f89fed688be8c3af783ed592a3a3eb /drivers/vfio
parentba4f184e126b751d1bffad5897f263108befc780 (diff)
vfio iommu: Add dma available capability
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> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio')
-rw-r--r--drivers/vfio/vfio_iommu_type1.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 5fbf0c1f7433..15e21dbffb16 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -2609,6 +2609,20 @@ static int vfio_iommu_migration_build_caps(struct vfio_iommu *iommu,
return vfio_info_add_capability(caps, &cap_mig.header, sizeof(cap_mig));
}
+static int vfio_iommu_dma_avail_build_caps(struct vfio_iommu *iommu,
+ struct vfio_info_cap *caps)
+{
+ struct vfio_iommu_type1_info_dma_avail cap_dma_avail;
+
+ cap_dma_avail.header.id = VFIO_IOMMU_TYPE1_INFO_DMA_AVAIL;
+ cap_dma_avail.header.version = 1;
+
+ cap_dma_avail.avail = iommu->dma_avail;
+
+ return vfio_info_add_capability(caps, &cap_dma_avail.header,
+ sizeof(cap_dma_avail));
+}
+
static int vfio_iommu_type1_get_info(struct vfio_iommu *iommu,
unsigned long arg)
{
@@ -2642,6 +2656,9 @@ static int vfio_iommu_type1_get_info(struct vfio_iommu *iommu,
ret = vfio_iommu_migration_build_caps(iommu, &caps);
if (!ret)
+ ret = vfio_iommu_dma_avail_build_caps(iommu, &caps);
+
+ if (!ret)
ret = vfio_iommu_iova_build_caps(iommu, &caps);
mutex_unlock(&iommu->lock);