On 30/11/2017 15:16, Pierre Morel wrote:
On 30/11/2017 13:57, Jean-Philippe Brucker wrote:
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)
indeed the error is to use uint64_t, I should *never* use this hardware
specific values but simply unsigned long and -1UL/~0U at this level.
Shouldn't the 52bit problem be reported by the iommu geometry?
Thanks,
Jean
Thanks, I will take care of this.
Pierre
--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany
