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From: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <5deb74db-19c7-6c5c-2089-22578cf17ad5@redhat.com>
Date: Thu, 1 Feb 2018 14:35:18 -0500
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Subject: Re: [Qemu-devel] [PATCH V8 1/4] mem: add share parameter to
 memory-backend-ram
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To: Eduardo Habkost <ehabkost@redhat.com>, Marcel Apfelbaum <marcel@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>, qemu-devel@nongnu.org, cohuck@redhat.com, f4bug@amsat.org, yuval.shaia@oracle.com, borntraeger@de.ibm.com, imammedo@redhat.com

On 01/02/2018 14:21, Eduardo Habkost wrote:
>> The device looks at its own private page tables, and not
>> to the OS ones.
> I'm still confused by your statement that the device builds its
> own [IOVA->PA] page table.  How would the device do that if it
> doesn't have access to the CPU MMU state?  Isn't the IOVA->PA
> translation table built by the OS?

The driver builds a page table for the device, either when it pins the
pages or by using MMU notifiers.

Paolo