From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4123wP0yxzzF327 for ; Fri, 8 Jun 2018 10:59:48 +1000 (AEST) Message-ID: Subject: Re: [RFC PATCH kernel 0/5] powerpc/P9/vfio: Pass through NVIDIA Tesla V100 From: Benjamin Herrenschmidt To: Alex Williamson Cc: Alexey Kardashevskiy , linuxppc-dev@lists.ozlabs.org, David Gibson , kvm-ppc@vger.kernel.org, Ram Pai , kvm@vger.kernel.org, Alistair Popple Date: Fri, 08 Jun 2018 10:58:54 +1000 In-Reply-To: <20180607183417.3ff2acf1@w520.home> References: <20180607084420.29513-1-aik@ozlabs.ru> <20180607110409.5057ebac@w520.home> <20180607161541.21df6434@w520.home> <33590885d138195c8ede78b588ddb03b132267fd.camel@kernel.crashing.org> <20180607183417.3ff2acf1@w520.home> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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.