linux-kernel - Re: [RFC PATCH 1/3] content: Add VIRTIO_F_SWIOTLB to negotiate use of SWIOTLB bounce buffers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <59be937432fe73b5781ecb04aad501ae5a11be23.camel@infradead.org>
Date: Thu, 03 Apr 2025 08:54:45 +0100
From: David Woodhouse <dwmw2@...radead.org>
To: "Michael S. Tsirkin" <mst@...hat.com>, Zhu Lingshan
 <lingshan.zhu@....com>
Cc: virtio-comment@...ts.linux.dev, hch@...radead.org, Claire Chang
 <tientzu@...omium.org>, linux-devicetree <devicetree@...r.kernel.org>, Rob
 Herring <robh+dt@...nel.org>, Jörg Roedel
 <joro@...tes.org>,  iommu@...ts.linux-foundation.org,
 linux-kernel@...r.kernel.org, graf@...zon.de
Subject: Re: [RFC PATCH 1/3] content: Add VIRTIO_F_SWIOTLB to negotiate use
 of SWIOTLB bounce buffers

On Thu, 2025-04-03 at 03:34 -0400, Michael S. Tsirkin wrote:
> 
> Indeed I personally do not exactly get why implement a virtual system
> without an IOMMU when virtio-iommu is available.
> 
> I have a feeling it's about lack of windows drivers for virtio-iommu
> at this point.

And a pKVM (etc.) implementation of virtio-iommu which would allow the
*trusted* part of the hypervisor to know which guest memory should be
shared with the VMM implementing the virtio device models?

You'd also end up in a situation where you have a virtio-iommu for some
devices, and a real two-stage IOMMU (e.g. SMMU or AMD's vIOMMU) for
other devices. Are guest operating systems going to cope well with
that? Do the available discovery mechanisms for all the relevant IOMMUs
even *allow* for that to be expressed?

Download attachment "smime.p7s" of type "application/pkcs7-signature" (5069 bytes)