On Tue, Sep 29, 2020 at 10:55:48AM +0200, Eric Auger wrote: > The current IOVA allocator allocates within the [0x10000, 1ULL << 39] > window, without paying attention to the host IOVA reserved regions. > This prevents NVMe passthtrough from working on ARM as the fixed > IOVAs rapidly grow up to the MSI reserved region [0x8000000, 0x8100000] > causing some VFIO MAP DMA failures. This series collects the usable > IOVA regions using VFIO GET_INFO (this requires the host to support > VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE) and rework the fixed and > temporary IOVA allocators to avoid those latter. > > For the time being we do not change the arbitrary min/max IOVAs. > In theory they could be dynamically determined but the kernel > currently fails to expose some HW limitations described in the ACPI > tables (such as PCI root complex Device Memory Address Size Limit). > See kernel thread related to "[RFC 0/3] iommu: Reserved regions for > IOVAs beyond dma_mask and iommu aperture" for more details: > https://lkml.org/lkml/2020/9/28/1102 > > Best Regards > > Eric > > This series can be found at: > https://github.com/eauger/qemu/tree/nvme_resv_v2 > > This was tested on ARM only. > > History: > v1 -> v2: > - remove "util/vfio-helpers: Dynamically compute the min/max IOVA" to > relax the kernel dependency > - Fix cabapbility enumeration loop > - set s->usable_iova_ranges=NULL to avoid double free > - handle possible u64 wrap > > Eric Auger (2): > util/vfio-helpers: Collect IOVA reserved regions > util/vfio-helpers: Rework the IOVA allocator to avoid IOVA reserved > regions > > util/vfio-helpers.c | 129 +++++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 123 insertions(+), 6 deletions(-) > > -- > 2.21.3 >
Thanks, applied to my block tree: https://github.com/stefanha/qemu/commits/block Stefan
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