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([2001:b07:6468:f312:38e0:ccf8:ca85:3d9b]) by smtp.gmail.com with ESMTPSA id t25sm719265wmj.18.2020.08.18.10.05.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 18 Aug 2020 10:05:17 -0700 (PDT) Subject: Re: [PATCH RFC v2 00/18] Add VFIO mediated device support and DEV-MSI support for the idxd driver To: Jason Gunthorpe Cc: "Tian, Kevin" , Alex Williamson , "Jiang, Dave" , "vkoul@kernel.org" , "Dey, Megha" , "maz@kernel.org" , "bhelgaas@google.com" , "rafael@kernel.org" , "gregkh@linuxfoundation.org" , "tglx@linutronix.de" , "hpa@zytor.com" , "Pan, Jacob jun" , "Raj, Ashok" , "Liu, Yi L" , "Lu, Baolu" , "Kumar, Sanjay K" , "Luck, Tony" , "Lin, Jing" , "Williams, Dan J" , "kwankhede@nvidia.com" , "eric.auger@redhat.com" , "parav@mellanox.com" , "Hansen, Dave" , "netanelg@mellanox.com" , "shahafs@mellanox.com" , "yan.y.zhao@linux.intel.com" , "Ortiz, Samuel" , "Hossain, Mona" , "dmaengine@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "x86@kernel.org" , "linux-pci@vger.kernel.org" , "kvm@vger.kernel.org" References: <20200724001930.GS2021248@mellanox.com> <20200805192258.5ee7a05b@x1.home> <20200807121955.GS16789@nvidia.com> <20200814133522.GE1152540@nvidia.com> <20200818004343.GG1152540@nvidia.com> <20200818115003.GM1152540@nvidia.com> <0711a4ce-1e64-a0cb-3e6d-f6653284e2e3@redhat.com> <20200818164903.GA1152540@nvidia.com> From: Paolo Bonzini Message-ID: <07fca197-3587-a45e-640b-bab0858067e2@redhat.com> Date: Tue, 18 Aug 2020 19:05:16 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200818164903.GA1152540@nvidia.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 18/08/20 18:49, Jason Gunthorpe wrote: > On Tue, Aug 18, 2020 at 06:27:21PM +0200, Paolo Bonzini wrote: >> On 18/08/20 13:50, Jason Gunthorpe wrote: >>> For instance, what about suspend/resume of containers using idxd? >>> Wouldn't you want to have the same basic approach of controlling the >>> wq from userspace that virtualization uses? >> >> The difference is that VFIO more or less standardizes the approach you >> use for live migration. With another interface you'd have to come up >> with something for every driver, and add support in CRIU for every >> driver as well. > > VFIO is very unsuitable for use as some general userspace. It only 1:1 > with a single process and just can't absorb what the existing idxd > userspace is doing. The point of mdev is that it's not 1:1 anymore. Paolo > So VFIO is already not a solution for normal userspace idxd where CRIU > becomes interesting. Not sure what you are trying to say? > > My point was the opposite, if you want to enable CRIU for idxd then > you probably need all the same stuff as for qemu/VFIO except in the > normal idxd user API. > > Jason >