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[70.30.145.63]) by smtp.gmail.com with ESMTPSA id v16-20020a05622a145000b003b8391b7736sm8671754qtx.25.2023.02.01.06.58.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Feb 2023 06:58:20 -0800 (PST) Date: Wed, 1 Feb 2023 09:58:19 -0500 From: Peter Xu To: Michal =?utf-8?B?UHLDrXZvem7DrWs=?= Cc: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= , "Dr. David Alan Gilbert" , qemu-devel@nongnu.org, Leonardo Bras Soares Passos , Juan Quintela Subject: Re: [PATCH 0/3] util/userfaultfd: Support /dev/userfaultfd Message-ID: References: <20230125224016.212529-1-peterx@redhat.com> <0f8ad497-202d-ae55-e468-77bb726a2699@redhat.com> <25b5b38e-3445-2e2e-cc34-e4feae6c0c09@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <25b5b38e-3445-2e2e-cc34-e4feae6c0c09@redhat.com> Received-SPF: pass client-ip=170.10.133.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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, 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 Wed, Feb 01, 2023 at 08:55:01AM +0100, Michal Prívozník wrote: > 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 Sounds good. Thanks. -- Peter Xu