From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Date: Fri, 08 Jun 2018 00:58:54 +0000 Subject: Re: [RFC PATCH kernel 0/5] powerpc/P9/vfio: Pass through NVIDIA Tesla V100 Message-Id: List-Id: References: <20180607084420.29513-1-aik@ozlabs.ru> <20180607110409.5057ebac@w520.home> <20180607161541.21df6434@w520.home> <33590885d138195c8ede78b588ddb03b132267fd.camel@kernel.crashing.org> <20180607183417.3ff2acf1@w520.home> In-Reply-To: <20180607183417.3ff2acf1@w520.home> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Alex Williamson Cc: kvm@vger.kernel.org, Alexey Kardashevskiy , Alistair Popple , Ram Pai , kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, David Gibson On Thu, 2018-06-07 at 18:34 -0600, Alex Williamson wrote: > > We *can* allow individual GPUs to be passed through, either if somebody > > designs a system without cross links, or if the user is ok with the > > security risk as the guest driver will not enable them if it doesn't > > "find" both sides of them. > > If GPUs are not isolated and we cannot prevent them from probing each > other via these links, then I think we have an obligation to configure > grouping in a way that doesn't rely on a benevolent userspace. Thanks, Well, it's a user decision, no ? Like how we used to let the user decide whether to pass-through things that have LSIs shared out of their domain. Cheers, Ben.