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From: Alex Williamson <alex.williamson@redhat.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Alex Mastro <amastro@fb.com>, Kevin Tian <kevin.tian@intel.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	David Reiss <dreiss@meta.com>, Joerg Roedel <joro@8bytes.org>,
	Keith Busch <kbusch@kernel.org>,
	Leon Romanovsky <leon@kernel.org>,
	Li Zhe <lizhe.67@bytedance.com>,
	Mahmoud Adam <mngyadam@amazon.de>,
	Philipp Stanner <pstanner@redhat.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Vivek Kasireddy <vivek.kasireddy@intel.com>,
	Will Deacon <will@kernel.org>, Yunxiang Li <Yunxiang.Li@amd.com>,
	linux-kernel@vger.kernel.org, iommu@lists.linux.dev,
	kvm@vger.kernel.org
Subject: Re: [TECH TOPIC] vfio, iommufd: Enabling user space drivers to vend more granular access to client processes
Date: Fri, 19 Sep 2025 09:57:43 -0600	[thread overview]
Message-ID: <20250919095743.482a00cd.alex.williamson@redhat.com> (raw)
In-Reply-To: <20250918225739.GS1326709@ziepe.ca>

On Thu, 18 Sep 2025 19:57:39 -0300
Jason Gunthorpe <jgg@ziepe.ca> wrote:
> 
> What I've been thinking is if the vending process could "dup" the FD
> and permanently attach a BPF program to the new FD that sits right
> after ioctl. The BPF program would inspect each ioctl when it is
> issued and enforce whatever policy the vending process wants.

Promising idea.

> What would give me alot of pause is your proposal where we effectively
> have the kernel enforce some arbitary policy, and I know from
> experience there will be endless asks for more and more policy
> options.

Definitely.  Also, is this at all considering the work that's gone into
vfio-user?  The long running USD sounds a lot like a vfio-user server,
where if we're using vfio-user's socket interface we'd have a lot of
opportunity to implement policy there and dma-bufs might be a means to
expose direct, restricted access.  Thanks,

Alex


  parent reply	other threads:[~2025-09-19 15:57 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-18 21:44 [TECH TOPIC] vfio, iommufd: Enabling user space drivers to vend more granular access to client processes Alex Mastro
2025-09-18 22:57 ` Jason Gunthorpe
2025-09-18 23:24   ` Keith Busch
2025-09-19  7:00     ` Tian, Kevin
2025-09-19 11:58       ` Jason Gunthorpe
2025-09-22  9:14       ` Mostafa Saleh
2025-09-22 17:46         ` Alex Mastro
2025-09-22 17:51           ` Jason Gunthorpe
2025-09-19 11:56     ` Jason Gunthorpe
2025-09-19 15:57   ` Alex Williamson [this message]
2025-09-19 17:14     ` Alex Mastro
2025-09-19 16:13   ` Alex Mastro

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