Messages in this thread | | | Subject | Re: [PATCH] vfio/iommu_type1: report the IOMMU aperture info | From | Jean-Philippe Brucker <> | Date | Thu, 30 Nov 2017 12:57:56 +0000 |
| |
Hello,
On 30/11/17 11:34, Pierre Morel wrote: [...] > +/** > + * vfio_get_aperture - report minimal aperture of a vfio_iommu > + * @iommu: the current vfio_iommu > + * @start: a pointer to the aperture start > + * @end : a pointer to the aperture end > + * > + * This function iterate on the domains using the given vfio_iommu > + * and restrict the aperture to the minimal aperture common > + * to all domains sharing this vfio_iommu. > + */ > +static void vfio_get_aperture(struct vfio_iommu *iommu, uint64_t *start, > + uint64_t *end) > +{ > + struct iommu_domain_geometry geometry; > + struct vfio_domain *domain; > + > + *start = 0; > + *end = U64_MAX;
I wonder if the default values should also reflect what the VFIO implementation actually supports. Looking at vfio_dma_do_map, a 32-bit host will reject any iova greater than 32 bits. In addition, vfio_dma_do_unmap doesn't support unmapping the last page of a 64-bit address space (existing IOMMUs would probably reject map requests with IOVA > 52 bits anyway, but if they don't report a domain aperture, VFIO can't guess it).
I think it's convenient to use VFIO_IOMMU_UNMAP_DMA on the full address space when an unmap-all is needed, maybe we could provide default aperture values that help doing this? (~0U for 32-bit and (~0ULL - PAGE_SIZE) for 64-bit)
Thanks, Jean
| |