linux-kernel - Re: [RFC PATCH 00/12] Private MMIO support for private assigned dev

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20250516124953.GD613512@nvidia.com>
Date: Fri, 16 May 2025 09:49:53 -0300
From: Jason Gunthorpe <jgg@...dia.com>
To: Xu Yilun <yilun.xu@...ux.intel.com>
Cc: Zhi Wang <zhiw@...dia.com>, Alexey Kardashevskiy <aik@....com>,
	kvm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
	linux-media@...r.kernel.org, linaro-mm-sig@...ts.linaro.org,
	sumit.semwal@...aro.org, christian.koenig@....com,
	pbonzini@...hat.com, seanjc@...gle.com, alex.williamson@...hat.com,
	vivek.kasireddy@...el.com, dan.j.williams@...el.com,
	yilun.xu@...el.com, linux-coco@...ts.linux.dev,
	linux-kernel@...r.kernel.org, lukas@...ner.de, yan.y.zhao@...el.com,
	daniel.vetter@...ll.ch, leon@...nel.org, baolu.lu@...ux.intel.com,
	zhenzhong.duan@...el.com, tao1.su@...el.com
Subject: Re: [RFC PATCH 00/12] Private MMIO support for private assigned dev

On Fri, May 16, 2025 at 02:19:45PM +0800, Xu Yilun wrote:
> > I don't know why you'd disable a viommu while the VM is running,
> > doesn't make sense.
> 
> Here it means remove the CC setup for viommu, shared setup is still
> kept.

That might makes sense for the vPCI function, but not the vIOMMU. A
secure VIOMMU needs to be running at all times while the guest is
running. Perhaps it has no devices it can be used with, but it's
functionality has to be there because a driver in the VM will be
connected to it.

At most "bind" should only tell the already existing secure vIOMMU
that it is allowed to translate for a specific vPCI function.

Jason