From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH v2 1/3] iommu/virtio: Add topology description to
 virtio-iommu config space
Date: Wed, 4 Mar 2020 18:34:42 +0100
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To: Jacob Pan <jacob.jun.pan@intel.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>, Jean-Philippe Brucker <jean-philippe@linaro.org>, kevin.tian@intel.com, linux-pci@vger.kernel.org, jasowang@redhat.com, virtualization@lists.linux-foundation.org, iommu@lists.linux-foundation.org, sebastien.boeuf@intel.com, bhelgaas@google.com, robin.murphy@arm.com
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On Wed, Mar 04, 2020 at 07:48:54AM -0800, Jacob Pan wrote:
> For emulated VT-d IOMMU, GIOVA can also be build as first level page
> tables then pass to the host IOMMU to bind. There is no need to shadow
> in this case, pIOMMU will do nested translation and walk guest page
> tables.

Right, but that requires hardware support. A pure software emulation of
VT-d requires the full shadow of the guest io-page-table.

> I thought we have the universal device properties to abstract DT and
> ACPI (via _DSD). Is that an option?

I don't know whether this was considered, Jean-Philippe?


Regards,

	Joerg