On Mon, Nov 28, 2022 at 06:53:12PM +0100, Eric Auger wrote:
+static int iommufd_vfio_map_dma(struct iommufd_ctx *ictx, unsigned int cmd,
void __user *arg)+{
- u32 supported_flags = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE;
- size_t minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
- struct vfio_iommu_type1_dma_map map;
- int iommu_prot = IOMMU_CACHE;
- struct iommufd_ioas *ioas;
- unsigned long iova;
- int rc;
- if (copy_from_user(&map, arg, minsz))
return -EFAULT;- if (map.argsz < minsz || map.flags & ~supported_flags)
return -EINVAL;- if (map.flags & VFIO_DMA_MAP_FLAG_READ)
iommu_prot |= IOMMU_READ;- if (map.flags & VFIO_DMA_MAP_FLAG_WRITE)
iommu_prot |= IOMMU_WRITE;- ioas = get_compat_ioas(ictx);
- if (IS_ERR(ioas))
return PTR_ERR(ioas);- /*
* Maps created through the legacy interface always use VFIO compatible* rlimit accounting. If the user wishes to use the faster user based* rlimit accounting then they must use the new interface.s/they/he
"they" has become a common neutral singular pronoun in English.
+static int iommufd_vfio_unmap_dma(struct iommufd_ctx *ictx, unsigned int cmd,
void __user *arg)+{
- size_t minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, size);
- /*
* VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP is obsoleted by the new* dirty tracking direction:* https://lore.kernel.org/kvm/20220731125503.142683-1-yishaih@nvidia.com/* https://lore.kernel.org/kvm/20220428210933.3583-1-joao.m.martins@oracle.com/*/- u32 supported_flags = VFIO_DMA_UNMAP_FLAG_ALL;
- struct vfio_iommu_type1_dma_unmap unmap;
- unsigned long unmapped = 0;
- struct iommufd_ioas *ioas;
- int rc;
- if (copy_from_user(&unmap, arg, minsz))
return -EFAULT;- if (unmap.argsz < minsz || unmap.flags & ~supported_flags)
return -EINVAL;- ioas = get_compat_ioas(ictx);
- if (IS_ERR(ioas))
return PTR_ERR(ioas);- if (unmap.flags & VFIO_DMA_UNMAP_FLAG_ALL) {
if (unmap.iova != 0 || unmap.size != 0) {rc = -EINVAL;goto err_put;}rc = iopt_unmap_all(&ioas->iopt, &unmapped);- } else {
if (READ_ONCE(ioas->iopt.disable_large_pages)) {unsigned long iovas[] = { unmap.iova + unmap.size - 1,unmap.iova - 1 };rc = iopt_cut_iova(&ioas->iopt, iovas,unmap.iova ? 2 : 1);please can you add a comment to explain what this is supposed to do?
iova -1 when iova == 0 will underflow and becomes garbage
/* * Create cuts at the start and last of the requested * range. If the start IOVA is 0 then it doesn't need to * be cut. */
+static int iommufd_vfio_set_iommu(struct iommufd_ctx *ictx, unsigned long type) +{
- struct iommufd_ioas *ioas = NULL;
- int rc = 0;
- if (type != VFIO_TYPE1_IOMMU && type != VFIO_TYPE1v2_IOMMU)
return -EINVAL;- /* VFIO fails the set_iommu if there is no group */
- ioas = get_compat_ioas(ictx);
- if (IS_ERR(ioas))
return PTR_ERR(ioas);- if (type == VFIO_TYPE1_IOMMU)
rc = iopt_disable_large_pages(&ioas->iopt);please can you document/explain this setting?
/* * The difference between TYPE1 and TYPE1v2 is the ability to unmap in * the middle of mapped ranges. This is complicated by huge page support * which creates single large IOPTEs that cannot be split by the iommu * driver. TYPE1 is very old at this point and likely nothing uses it, * however it is simple enough to emulate by simply disabling the * problematic large IOPTEs. Then we can safely unmap within any range. */
Thanks, Jason