Re: [Qemu-devel] [PATCH for 2.9] vhost: generalize iommu memory region

[Maxime Coquelin]

On 03/29/2017 06:10 AM, Jason Wang wrote:
> We assumes the iommu_ops were attached to the root region of address
> space. This may not be true for all kinds of IOMMU implementation and
> especially after commit 3716d5902d74 ("pci: introduce a bus master
> container"). So fix this by not assuming as->root has iommu_ops,
> instead depending on the regions reported by memory listener through:
>
> - register a memory listener to dma_as
> - during region_add, if it's a region of IOMMU, register a specific
>   IOMMU notifier, and store all notifiers in a list.
> - during region_del, compare and delete the IOMMU notifier from the list
>
> This is also a must for making vhost device IOTLB works for all types
> of IOMMUs. Note, since we register one notifier during each
> .region_add, the IOTLB may be flushed more than one times, this is
> suboptimal and could be optimized in the future.
>
> Reported-by: Maxime Coquelin <address@hidden>
> Fixes: 3716d5902d74 ("pci: introduce a bus master container")
> Cc: Peter Xu <address@hidden>
> Signed-off-by: Jason Wang <address@hidden>
> ---
>  hw/virtio/vhost.c         | 84 ++++++++++++++++++++++++++++++++++++-----------
>  include/hw/virtio/vhost.h | 11 +++++++
>  2 files changed, 75 insertions(+), 20 deletions(-)

Tested-by: Maxime Coquelin <address@hidden>

Thanks!
Maxime