On 17/09/15 15:09, David Gibson wrote:
> When we have guest visible IOMMUs, we allow notifiers to be registered
> which will be informed of all changes to IOMMU mappings. This is used by
> vfio to keep the host IOMMU mappings in sync with guest IOMMU mappings.
>
> However, unlike with a memory region listener, an iommu notifier won't be
> told about any mappings which already exist in the (guest) IOMMU at the
> time it is registered. This can cause problems if hotplugging a VFIO
> device onto a guest bus which had existing guest IOMMU mappings, but didn't
> previously have an VFIO devices (and hence no host IOMMU mappings).
>
> This adds a memory_region_register_iommu_notifier_replay() function to
> handle this case. As well as registering the new notifier it replays
> existing mappings. Because the IOMMU memory region doesn't internally
> remember the granularity of the guest IOMMU it has a small hack where the
> caller must specify a granularity at which to replay mappings.
>
> If there are finer mappings in the guest IOMMU these will be reported in
> the iotlb structures passed to the notifier which it must handle (probably
> causing it to flag an error). This isn't new - the VFIO iommu notifier
> must already handle notifications about guest IOMMU mappings too short
> for it to represent in the host IOMMU.
>
> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
> ---
> include/exec/memory.h | 16 ++++++++++++++++
> memory.c | 18 ++++++++++++++++++
> 2 files changed, 34 insertions(+)
> diff --git a/memory.c b/memory.c
> index 0d8b2d9..6b5a2f1 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -1403,6 +1403,24 @@ void
> memory_region_register_iommu_notifier(MemoryRegion *mr, Notifier *n)
> notifier_list_add(&mr->iommu_notify, n);
> }
>
> +void memory_region_register_iommu_notifier_replay(MemoryRegion *mr, Notifier
> *n,
> + hwaddr granularity, bool
> is_write)
granularity itself is not an address, but a size, isn't it? So using
"hwaddr" sounds wrong here.
> +{
> + hwaddr addr;
dma_addr_t ?
> + IOMMUTLBEntry iotlb;
> +
> + memory_region_register_iommu_notifier(mr, n);
> +
> + for (addr = 0;
> + int128_lt(int128_make64(addr), mr->size);
> + addr += granularity) {
> +
> + iotlb = mr->iommu_ops->translate(mr, addr, is_write);
> + if (iotlb.perm != IOMMU_NONE)
> + n->notify(n, &iotlb);
Missing curly braces.
> + }
> +}
> +
Thomas
