From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH 0/3] Fix virtio-blk issue with SWIOTLB
Date: Fri, 11 Jan 2019 10:15:02 +0100
Message-ID: <20190111091502.GC5825__26613.9116058641$1547692985$gmane$org@8bytes.org>
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	<5ae1341e-62ec-0478-552b-259eabf9fb17@redhat.com>
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To: Jason Wang <jasowang@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>, jon.grimm@amd.com, brijesh.singh@amd.com, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, jfehlig@suse.com, "Michael S . Tsirkin" <mst@redhat.com>, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-block@vger.kernel.org, iommu@lists.linux-foundation.org, hch@lst.de
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On Fri, Jan 11, 2019 at 11:29:31AM +0800, Jason Wang wrote:
> Just wonder if my understanding is correct IOMMU_PLATFORM must be set for
> all virtio devices under AMD-SEV guests?

Yes, that is correct. Emulated DMA can only happen on the SWIOTLB
aperture, because that memory is not encrypted. The guest bounces the
data then to its encrypted memory.

Regards,

	Joerg