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Re: [Qemu-devel] [PATCH v4 1/3] memory: introduce IOMMUNotifier and its
From: |
David Gibson |
Subject: |
Re: [Qemu-devel] [PATCH v4 1/3] memory: introduce IOMMUNotifier and its caps |
Date: |
Wed, 14 Sep 2016 20:50:38 +1000 |
User-agent: |
Mutt/1.7.0 (2016-08-17) |
On Wed, Sep 14, 2016 at 04:17:26PM +0800, Peter Xu wrote:
> On Wed, Sep 14, 2016 at 05:15:03PM +1000, David Gibson wrote:
>
> [...]
>
> > Peter suggested commenting this next to the IOTLBEntry definition, and
> > I think that's probably ok for now.
>
> Looks like we have something already (just not that obvious):
>
> /**
> * memory_region_notify_iommu: notify a change in an IOMMU translation entry.
> *
> * @mr: the memory region that was changed
> * @entry: the new entry in the IOMMU translation table. The entry
> * replaces all old entries for the same virtual I/O address range.
> * Deleted entries have address@hidden == 0.
> */
> void memory_region_notify_iommu(MemoryRegion *mr,
> IOMMUTLBEntry entry);
>
> Though it's quite simple, it did explain that perm==0 is for deleted
> entries.
That is definitely not sufficient. It misses the crucial point is
that @perm != 0 is NOT ALLOWED if there was an existing mapping at
that address.
It's not that we really _need_ to support in-place change. The point
is that we want to keep our interface contracts simple and clear.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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[Qemu-devel] [PATCH v4 2/3] memory: introduce IOMMUOps.notify_flag_changed, Peter Xu, 2016/09/08
- Re: [Qemu-devel] [PATCH v4 2/3] memory: introduce IOMMUOps.notify_flag_changed, David Gibson, 2016/09/14
- Re: [Qemu-devel] [PATCH v4 2/3] memory: introduce IOMMUOps.notify_flag_changed, Peter Xu, 2016/09/14
- Re: [Qemu-devel] [PATCH v4 2/3] memory: introduce IOMMUOps.notify_flag_changed, David Gibson, 2016/09/14
- Re: [Qemu-devel] [PATCH v4 2/3] memory: introduce IOMMUOps.notify_flag_changed, Peter Xu, 2016/09/14
- Re: [Qemu-devel] [PATCH v4 2/3] memory: introduce IOMMUOps.notify_flag_changed, David Gibson, 2016/09/14
- Re: [Qemu-devel] [PATCH v4 2/3] memory: introduce IOMMUOps.notify_flag_changed, Peter Xu, 2016/09/14
[Qemu-devel] [PATCH v4 3/3] intel_iommu: allow UNMAP notifiers, Peter Xu, 2016/09/08
Re: [Qemu-devel] [PATCH v4 0/3] Introduce IOMMUNotifier struct, no-reply, 2016/09/09