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[142.167.219.86]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7c5f777e02bsm720145285a.110.2025.04.01.16.52.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Apr 2025 16:52:25 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1tzlP7-00000001SiZ-1Xz1; Tue, 01 Apr 2025 20:52:25 -0300 Date: Tue, 1 Apr 2025 20:52:25 -0300 From: Jason Gunthorpe To: Wathsala Wathawana Vithanage Cc: "Tian, Kevin" , Alex Williamson , "linux-kernel@vger.kernel.org" , nd , Philipp Stanner , Yunxiang Li , "Dr. David Alan Gilbert" , Ankit Agrawal , "open list:VFIO DRIVER" , Dhruv Tripathi , Honnappa Nagarahalli , Jeremy Linton Subject: Re: [RFC PATCH] vfio/pci: add PCIe TPH to device feature ioctl Message-ID: <20250401235225.GA327284@ziepe.ca> References: <20250221224638.1836909-1-wathsala.vithanage@arm.com> <20250304141447.GY5011@ziepe.ca> <20250304182421.05b6a12f.alex.williamson@redhat.com> <20250401141138.GE186258@ziepe.ca> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Apr 01, 2025 at 11:38:01PM +0000, Wathsala Wathawana Vithanage wrote: > > Really we can't block device specific mode anyhow because we can't even > > discover it on the kernel side.. > > We cannot block users from writing a steering-tag to a device specific location, but > can we use a capability to prevent users from enabling device specific mode on the device? qemu could do that, but the vfio kernel side really shouldn't.. There is no reason vfio userspace on bare metal couldn't use device specific mode. Jason