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vfio: Find DMA available capability

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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>
This commit is contained in:
Matthew Rosato 2020-10-26 11:34:33 -04:00 committed by Alex Williamson
parent 3ab7a0b40d
commit 7486a62845
2 changed files with 33 additions and 0 deletions
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31
hw/vfio/common.c
View File

@ -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)
{

2
include/hw/vfio/vfio-common.h
View File

@ -214,6 +214,8 @@ int vfio_get_dev_region_info(VFIODevice *vbasedev, uint32_t type,
bool vfio_has_region_cap(VFIODevice *vbasedev, int region, uint16_t cap_type);
struct vfio_info_cap_header *
vfio_get_region_info_cap(struct vfio_region_info *info, uint16_t id);
bool vfio_get_info_dma_avail(struct vfio_iommu_type1_info *info,
unsigned int *avail);
#endif
extern const MemoryListener vfio_prereg_listener;