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Re: [Qemu-devel] [PATCH 1/2] intel_iommu: Fix root_scalable migration br
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From: |
Yi Sun |
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Subject: |
Re: [Qemu-devel] [PATCH 1/2] intel_iommu: Fix root_scalable migration breakage |
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Date: |
Fri, 29 Mar 2019 09:51:06 +0800 |
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User-agent: |
Mutt/1.5.21 (2010-09-15) |
On 19-03-28 18:49:32, Peter Xu wrote:
> When introducing the initial support for scalable mode we added a
> new field into vmstate however we blindly migrate that field without
> notice. That'll break migration no matter forward or backward.
>
Just curious, what is the scenario to break migration? From latest
qemu integrated scalable mode patches to an old qemu without scalable
mode?
The changes look good to me. Thanks for the fix!
Reviewed-by: Yi Sun <address@hidden>
> The normal way should be that we use something like
> VMSTATE_UINT32_TEST() or subsections for the new vmstate field however
> for this case of vt-d we can even make it simpler because we've
> already migrated all the registers and it'll be fairly simple that we
> re-generate root_scalable field from the register values during post
> load of the device.
>
> Fixes: fb43cf739e ("intel_iommu: scalable mode emulation")
> Signed-off-by: Peter Xu <address@hidden>