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([2001:b07:6468:f312:7009:9cf0:6204:f570]) by smtp.gmail.com with ESMTPSA id u18sm9565548wrt.26.2019.12.20.01.50.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 20 Dec 2019 01:50:53 -0800 (PST) Subject: Re: [RFC v4 PATCH 00/49] Initial support of multi-process qemu - status update To: Stefan Hajnoczi , =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= References: <20191210064716.GA6401@flaka> <20191213104116.GB1180977@stefanha-x1.localdomain> <20191216194655.GA5922@flaka> <20191217163316.GB1333385@stefanha-x1.localdomain> <20191219115545.GD1624084@stefanha-x1.localdomain> <772D9CF3-D15D-42D1-B9CF-1279619D7C20@nutanix.com> <20191219125504.GI1190276@redhat.com> <20191220094712.GA1635864@stefanha-x1.localdomain> From: Paolo Bonzini Message-ID: Date: Fri, 20 Dec 2019 10:50:54 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20191220094712.GA1635864@stefanha-x1.localdomain> Content-Language: en-US X-MC-Unique: sbHB-6jgOC-hjQ2GOCMFSQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Elena Ufimtseva , "fam@euphon.net" , Swapnil Ingle , "john.g.johnson@oracle.com" , "qemu-devel@nongnu.org" , "Walker, Benjamin" , "kraxel@redhat.com" , "jag.raman@oracle.com" , "Harris, James R" , "quintela@redhat.com" , "mst@redhat.com" , "armbru@redhat.com" , "kanth.ghatraju@oracle.com" , Felipe Franciosi , "thuth@redhat.com" , "ehabkost@redhat.com" , "konrad.wilk@oracle.com" , "dgilbert@redhat.com" , "liran.alon@oracle.com" , "rth@twiddle.net" , "kwolf@redhat.com" , "mreitz@redhat.com" , "ross.lagerwall@citrix.com" , "marcandre.lureau@gmail.com" , Thanos Makatos Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 20/12/19 10:47, Stefan Hajnoczi wrote: >> If it doesn't create too large of a burden to support both, then I think >> it is very desirable. IIUC, this is saying a kernel based solution as th= e >> optimized/optimal solution, and userspace UNIX socket based option as th= e >> generic "works everywhere" fallback solution. > I'm slightly in favor of the kernel implementation because it keeps us > better aligned with VFIO. That means solving problems in one place only > and less reinventing the wheel. I think there are anyway going to be some differences with VFIO. For example, currently VFIO requires pinning user memory. Is that a limitation for muser too? If so, that would be a big disadvantage; if not, however, management tools need to learn that muser devices unlike other VFIO devices do not prevent overcommit. Paolo