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Re: [PATCH 00/13] VIRTIO-IOMMU/VFIO: Don't assume 64b IOVA space
From: |
Alex Williamson |
Subject: |
Re: [PATCH 00/13] VIRTIO-IOMMU/VFIO: Don't assume 64b IOVA space |
Date: |
Tue, 5 Sep 2023 11:55:58 -0600 |
On Mon, 4 Sep 2023 10:03:43 +0200
Eric Auger <eric.auger@redhat.com> wrote:
> On x86, when assigning VFIO-PCI devices protected with virtio-iommu
> we encounter the case where the guest tries to map IOVAs beyond 48b
> whereas the physical VTD IOMMU only supports 48b. This ends up with
> VFIO_MAP_DMA failures at qemu level because at kernel level,
> vfio_iommu_iova_dma_valid() check returns false on vfio_map_do_map().
>
> This is due to the fact the virtio-iommu currently unconditionally
> exposes an IOVA range of 64b through its config input range fields.
>
> This series removes this assumption by retrieving the usable IOVA
> regions through the VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE UAPI when
> a VFIO device is attached. This info is communicated to the
> virtio-iommu memory region, transformed into the inversed info, ie.
> the host reserved IOVA regions. Then those latter are combined with the
> reserved IOVA regions set though the virtio-iommu reserved-regions
> property. That way, the guest virtio-iommu driver, unchanged, is
> able to probe the whole set of reserved regions and prevent any IOVA
> belonging to those ranges from beeing used, achieving the original goal.
Hi Eric,
I don't quite follow this relative to device hotplug. Are we
manipulating a per-device memory region which is created at device add
time? Is that memory region actually shared in some cases, for instance
if we have a PCIe-to-PCI bridge aliasing devices on the conventional
side? Thanks,
Alex
> This series can be found at:
> https://github.com/eauger/qemu/tree/virtio-iommu_geometry_v1
>
> Eric Auger (13):
> memory: Let ReservedRegion use Range
> memory: Introduce memory_region_iommu_set_iova_ranges
> vfio: Collect container iova range info
> virtio-iommu: Rename reserved_regions into prop_resv_regions
> virtio-iommu: Introduce per IOMMUDevice reserved regions
> range: Introduce range_inverse_array()
> virtio-iommu: Implement set_iova_ranges() callback
> range: Make range_compare() public
> util/reserved-region: Add new ReservedRegion helpers
> virtio-iommu: Consolidate host reserved regions and property set ones
> test: Add some tests for range and resv-mem helpers
> virtio-iommu: Resize memory region according to the max iova info
> vfio: Remove 64-bit IOVA address space assumption
>
> include/exec/memory.h | 30 ++++-
> include/hw/vfio/vfio-common.h | 2 +
> include/hw/virtio/virtio-iommu.h | 7 +-
> include/qemu/range.h | 9 ++
> include/qemu/reserved-region.h | 32 +++++
> hw/core/qdev-properties-system.c | 9 +-
> hw/vfio/common.c | 70 ++++++++---
> hw/virtio/virtio-iommu-pci.c | 8 +-
> hw/virtio/virtio-iommu.c | 85 +++++++++++--
> softmmu/memory.c | 15 +++
> tests/unit/test-resv-mem.c | 198 +++++++++++++++++++++++++++++++
> util/range.c | 41 ++++++-
> util/reserved-region.c | 94 +++++++++++++++
> hw/virtio/trace-events | 1 +
> tests/unit/meson.build | 1 +
> util/meson.build | 1 +
> 16 files changed, 562 insertions(+), 41 deletions(-)
> create mode 100644 include/qemu/reserved-region.h
> create mode 100644 tests/unit/test-resv-mem.c
> create mode 100644 util/reserved-region.c
>
- [PATCH 11/13] test: Add some tests for range and resv-mem helpers, (continued)
- [PATCH 11/13] test: Add some tests for range and resv-mem helpers, Eric Auger, 2023/09/04
- [PATCH 13/13] vfio: Remove 64-bit IOVA address space assumption, Eric Auger, 2023/09/04
- [PATCH 12/13] virtio-iommu: Resize memory region according to the max iova info, Eric Auger, 2023/09/04
- [PATCH 08/13] range: Make range_compare() public, Eric Auger, 2023/09/04
- [PATCH 10/13] virtio-iommu: Consolidate host reserved regions and property set ones, Eric Auger, 2023/09/04
- Re: [PATCH 00/13] VIRTIO-IOMMU/VFIO: Don't assume 64b IOVA space, YangHang Liu, 2023/09/05
- Re: [PATCH 00/13] VIRTIO-IOMMU/VFIO: Don't assume 64b IOVA space,
Alex Williamson <=