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Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest
From: |
Peter Xu |
Subject: |
Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits |
Date: |
Mon, 12 Dec 2016 10:01:15 +0800 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Sun, Dec 11, 2016 at 05:13:45AM +0200, Michael S. Tsirkin wrote:
> On Wed, Dec 07, 2016 at 01:52:45PM +0800, Peter Xu wrote:
> > Previously vt-d codes only supports 39 bits iova address width. It won't
> > be hard to extend it to 48 bits.
> >
> > After enabling this, we should be able to map larger iova addresses.
> >
> > To check whether 48 bits aw is enabled, we can grep in the guest dmesg
> > with line: "dmar: Host address width 48" (previously it was 39).
> >
> > Signed-off-by: Peter Xu <address@hidden>
>
> I suspect we can't do this for old machine types.
> Need to behave in compatible ways.
Sure. I can do that.
Btw, is vt-d iommu still in experimental stage? I am just thinking
whether it'll be overkill we add lots of tunables before we have one
stable and mature vt-d emulation.
> Also, is 48 always enough? 5 level with 57 bits
> is just around the corner.
Please refer to the discussion with Jason - looks like vt-d spec
currently supports only 39/48 bits address width? Please correct if I
made a mistake.
> And is it always supported? for things like vfio
> to work, don't we need to check what does host support?
Hmm, yes, we should do that. But until now, we still don't have a
complete vfio support. IMHO we can postpone this issue until vfio is
fully supported.
Thanks,
-- peterx
[Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits, Peter Xu, 2016/12/07
- Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits, Jason Wang, 2016/12/07
- Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits, Michael S. Tsirkin, 2016/12/10
- Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits,
Peter Xu <=
- Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits, Alex Williamson, 2016/12/12
- Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits, Peter Xu, 2016/12/12
- Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits, Alex Williamson, 2016/12/12
- Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits, Peter Xu, 2016/12/13
- Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits, Alex Williamson, 2016/12/13
- Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits, Peter Xu, 2016/12/13
- Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits, Alex Williamson, 2016/12/13
- Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits, Michael S. Tsirkin, 2016/12/13
Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits, Tian, Kevin, 2016/12/13
Re: [Qemu-devel] [PATCH for-2.9 2/2] intel_iommu: extend supported guest aw to 48 bits, Alex Williamson, 2016/12/13