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Subject: Re: [PATCH v12 14/21] powerpc/powernv: Allocate struct pnv_ioda_pe
 iommu_table dynamically
From: Benjamin Herrenschmidt <benh@au1.ibm.com>
To: Wei Yang <weiyang@linux.vnet.ibm.com>
Date: Mon, 02 Mar 2015 18:56:19 +1100
In-Reply-To: <20150302075036.GH21571@richard>
References: <20150224082939.32124.45744.stgit@bhelgaas-glaptop2.roam.corp.google.com>
 <20150224083435.32124.65099.stgit@bhelgaas-glaptop2.roam.corp.google.com>
 <20150224084653.GI6220@google.com> <20150302075036.GH21571@richard>
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Cc: Bjorn Helgaas <bhelgaas@google.com>, linux-pci@vger.kernel.org,
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On Mon, 2015-03-02 at 15:50 +0800, Wei Yang wrote:
> >
> >Is there a hotplug remove path where we should also be calling
> >iommu_free_table()?
> 
> When VF is not introduced, no one calls this on powernv platform.
> 
> Each PCI bus is a PE and it has its own iommu table, even a device is
> hotpluged, the iommu table will not be released.

Actually, I believe Alexey patches to add support for dynamic DMA
windows for KVM guests using VFIO will also alloc/free iommu tables. In
fact his patches somewhat change quite a few things in that area, and
I'm currently reviewing them.

Wei, can you post a new series when you've finished sync'ing with
Bjorn ? At that point, I'll try to work with Alexey to evaluate the
impact of his changes on your patches.

Cheers,
Ben.