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[213.175.37.10]) by smtp.gmail.com with ESMTPSA id g12-20020a170906868c00b00887f0f8294esm4702102ejx.200.2023.01.31.23.55.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 31 Jan 2023 23:55:01 -0800 (PST) Message-ID: <25b5b38e-3445-2e2e-cc34-e4feae6c0c09@redhat.com> Date: Wed, 1 Feb 2023 08:55:01 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: Re: [PATCH 0/3] util/userfaultfd: Support /dev/userfaultfd Content-Language: en-US To: Peter Xu , =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= Cc: "Dr. David Alan Gilbert" , qemu-devel@nongnu.org, Leonardo Bras Soares Passos , Juan Quintela References: <20230125224016.212529-1-peterx@redhat.com> <0f8ad497-202d-ae55-e468-77bb726a2699@redhat.com> From: =?UTF-8?B?TWljaGFsIFByw612b3puw61r?= In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=mprivozn@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.09, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 1/31/23 22:01, Peter Xu wrote: > I'll wait 1-2 more days to see whether Michal has anything to comment. Yeah, we can go with your patches and leave FD passing for future work. It's orthogonal after all. In the end we can have (in the order of precedence): 1) new cmd line argument, say: qemu-system-x86_64 -userfaultfd fd=5 # where FD 5 is passed by libvirt when exec()-ing qemu, just like other FDs, e.g. -chardev socket,fd=XXX 2) your patches, where qemu opens /dev/userfaultfd 3) current behavior, userfaultfd syscall Michal