diff mbox series

[v3,3/5] vfio: Find DMA available capability

Message ID 1600197283-25274-4-git-send-email-mjrosato@linux.ibm.com
State New
Headers show
Series s390x/pci: Accomodate vfio DMA limiting | expand

Commit Message

Matthew Rosato Sept. 15, 2020, 7:14 p.m. UTC 
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>
---
 hw/vfio/common.c              | 31 +++++++++++++++++++++++++++++++
 include/hw/vfio/vfio-common.h |  2 ++
 2 files changed, 33 insertions(+)

Comments

Cornelia Huck Sept. 16, 2020, 10:01 a.m. UTC | #1 
On Tue, 15 Sep 2020 15:14:41 -0400
Matthew Rosato <mjrosato@linux.ibm.com> wrote:

> 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>

> ---

>  hw/vfio/common.c              | 31 +++++++++++++++++++++++++++++++

>  include/hw/vfio/vfio-common.h |  2 ++

>  2 files changed, 33 insertions(+)


Reviewed-by: Cornelia Huck <cohuck@redhat.com>
diff mbox series

Patch

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index eba7b55..50779f9 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -849,6 +849,37 @@  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)
 {
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index c78f3ff..661a380 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -178,6 +178,8 @@  VFIOGroup *vfio_get_group(int groupid, AddressSpace *as, Error **errp);
 void vfio_put_group(VFIOGroup *group);
 int vfio_get_device(VFIOGroup *group, const char *name,
                     VFIODevice *vbasedev, Error **errp);
+bool vfio_get_info_dma_avail(struct vfio_iommu_type1_info *info,
+                             unsigned int *avail);
 
 extern const MemoryRegionOps vfio_region_ops;
 typedef QLIST_HEAD(VFIOGroupList, VFIOGroup) VFIOGroupList;