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Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entr
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry |
Date: |
Tue, 6 Jun 2017 16:34:30 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.0 |
On 05/06/2017 05:07, Peter Xu wrote:
> I don't sure whether it'll be a good interface for IOTLB. AFAIU at
> least for VT-d, the IOMMU translation is page aligned which is defined
> by spec, so it makes sense that (again at least for VT-d) here we'd
> better just use page_mask/addr_mask.
>
> That's also how I know about IOMMU in general - I assume it do the
> translations always with page masks (never arbitary length), though
> page size can differ from platfrom to platform, that's why here the
> IOTLB interface used addr_mask, then it works for all platforms. I
> don't know whether I'm 100% correct here though.
>
> Maybe David/Paolo/... would comment as well?
I would ask David. There are PowerPC MMUs that allow fast lookup of
arbitrarily-sized windows (not necessarily power of two), so maybe the
IOMMUs can do the same.
Paolo
- [Qemu-devel] [PATCH 0/3] exec: further refine address_space_get_iotlb_entry(), Peter Xu, 2017/06/02
- [Qemu-devel] [PATCH 1/3] exec: add page_mask for address_space_do_translate, Peter Xu, 2017/06/02
- [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Peter Xu, 2017/06/02
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Michael S. Tsirkin, 2017/06/02
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Peter Xu, 2017/06/04
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry,
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, David Gibson, 2017/06/06
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Peter Xu, 2017/06/06
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Michael S. Tsirkin, 2017/06/07
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Peter Xu, 2017/06/08
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Michael S. Tsirkin, 2017/06/08
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Peter Xu, 2017/06/08
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, David Gibson, 2017/06/08
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Michael S. Tsirkin, 2017/06/11
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, David Gibson, 2017/06/11
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Peter Xu, 2017/06/11