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Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entr
From: |
David Gibson |
Subject: |
Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry |
Date: |
Sun, 11 Jun 2017 20:10:15 +0800 |
User-agent: |
Mutt/1.8.0 (2017-02-23) |
On Sun, Jun 11, 2017 at 01:09:26PM +0300, Michael S. Tsirkin wrote:
> On Fri, Jun 09, 2017 at 09:58:47AM +0800, Peter Xu wrote:
> > > > The problem is that when I was fixing the problem that vhost had with
> > > > PT (a764040, "exec: abstract address_space_do_translate()"), I did
> > > > broke the IOTLB translation a bit (it was using page masks). IMHO we
> > > > need to fix it first for correctness (patch 1/2).
> > > >
> > > > For patch 3, if we can have Jason's patch to allow dynamic
> > > > iommu_platform switching, that'll be the best, then I can rewrite
> > > > patch 3 with the switching logic rather than caching anything. But
> > > > IMHO that can be separated from patch 1/2 if you like.
> > > >
> > > > Or do you have better suggestion on how should we fix it?
> > > >
> > > > Thanks,
> > >
> > > Can we drop masks completely and replace with length? I think we
> > > should do that instead of trying to fix masks.
> >
> > Do you mean to modify IOMMUTLBEntry.addr_mask into length?
>
> I think it's better than alternatives.
>
> > Again, I am not sure this is good... At least we need to get ack from
> > David since spapr should be the initial user of it, and possibly also
> > Alex since vfio should be assuming that (IIUC both in QEMU and kernel)
> > addr_mask is page masks rather than arbirary length.
> >
> > (CC Alex)
> >
> > Thanks,
>
> Callbacks that need powers of two can easily split up the range.
I think I missed part of the thread. What's the original use case for
non-power-of-two IOTLB entries? It certainly won't happen on Power.
--
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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- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, (continued)
- 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, 2017/06/06
- 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 <=
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Peter Xu, 2017/06/11
- 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, Peter Xu, 2017/06/12
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Michael S. Tsirkin, 2017/06/14
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Peter Xu, 2017/06/14
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Peter Xu, 2017/06/14
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Michael S. Tsirkin, 2017/06/16
- Re: [Qemu-devel] [PATCH 2/3] exec: simplify address_space_get_iotlb_entry, Paolo Bonzini, 2017/06/07
[Qemu-devel] [PATCH 3/3] vhost: iommu: cache static mapping if there is, Peter Xu, 2017/06/02