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[Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support
From: |
Eduard - Gabriel Munteanu |
Subject: |
[Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support |
Date: |
Thu, 15 Jul 2010 02:11:00 +0300 |
User-agent: |
Mutt/1.5.20 (2009-06-14) |
On Wed, Jul 14, 2010 at 02:53:03PM +0100, Paul Brook wrote:
> > Memory accesses must go through the IOMMU layer.
>
> No. Devices should not know or care whether an IOMMU is present.
They don't really care. iommu_get() et al. are convenience functions
which can and do return NULL when there's no IOMMU and device code can
pass that NULL around without checking. I could've probably made the r/w
functions take only the DeviceState in addition to normal args, but
wanted to avoid looking up the related structures on each I/O operation.
> You should be adding a DeviceState argument to cpu_physical_memory_{rw,map}.
> This should then handle IOMMU translation transparently.
>
> You also need to accomodate the the case where multiple IOMMU are present.
>
> Paul
We don't assume there's a single IOMMU in the generic layer. The
callbacks within 'struct iommu' could very well dispatch the request to
one of multiple, coexisting IOMMUs.
Eduard
- Re: [Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support, (continued)
- Re: [Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support, Paul Brook, 2010/07/15
- Re: [Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support, Anthony Liguori, 2010/07/15
- Re: [Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support, Paul Brook, 2010/07/15
- Re: [Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support, Eduard - Gabriel Munteanu, 2010/07/14
- Re: [Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support, Joerg Roedel, 2010/07/15
- Re: [Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support, Paul Brook, 2010/07/15
- Re: [Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support, Joerg Roedel, 2010/07/15
- [Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support,
Eduard - Gabriel Munteanu <=
- [Qemu-devel] Re: [RFC PATCH 4/7] ide: IOMMU support, Paul Brook, 2010/07/15
[Qemu-devel] [RFC PATCH 7/7] ac97: IOMMU support, Eduard - Gabriel Munteanu, 2010/07/14
[Qemu-devel] [RFC PATCH 6/7] eepro100: IOMMU support, Eduard - Gabriel Munteanu, 2010/07/14
[Qemu-devel] [RFC PATCH 1/7] Generic IOMMU layer, Eduard - Gabriel Munteanu, 2010/07/14
[Qemu-devel] [RFC PATCH 5/7] rtl8139: IOMMU support, Eduard - Gabriel Munteanu, 2010/07/14
[Qemu-devel] [RFC PATCH 2/7] AMD IOMMU emulation, Eduard - Gabriel Munteanu, 2010/07/14