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client-ip=162.221.158.21; receiver=esa6.hc3370-68.iphmx.com; envelope-from="Ian.Jackson@citrix.com"; x-sender="postmaster@mail.citrix.com"; x-conformance=sidf_compatible Authentication-Results: esa6.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none; spf=None smtp.pra=ian.jackson@citrix.com; spf=Pass smtp.mailfrom=Ian.Jackson@citrix.com; spf=None smtp.helo=postmaster@mail.citrix.com; dmarc=pass (p=none dis=none) d=citrix.com IronPort-SDR: jv4vrkbNMnRObN497itbi0poQfmoPvTIHdb4n5BkSqqvLVc7tLvZYK76sE0bKRu+PgqjKFwv4Z N4VAVLzYYNnGFrCEKlViPTv32k4xLZPSPL80FQDPA4MN7J5tvrk6QGAidPfgbPo5S1iyT7BxAl HbjWz6e2u4Hhx+bSdh7LjOpv66Hq8JOrKddt7AEKI+fXT6NPIpOQo7o/RfNG0ITvWy1UbZJeeE ipMcwWJMuB12/MZUCcLMem+BFCXXKCcZnX3P+9Ro092YeH0jvGd8hjfAIwqQIFLSvQh1mhYbE6 YiU= X-SBRS: 2.7 X-MesageID: 17910432 X-Ironport-Server: esa6.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.73,392,1583211600"; d="scan'208";a="17910432" From: Ian Jackson MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit Message-ID: <24253.29774.668013.710363@mariner.uk.xensource.com> Date: Thu, 14 May 2020 17:39:42 +0100 To: Jason Andryuk Subject: Re: [PATCH v5 12/21] libxl: use vchan for QMP access with Linux stubdomain In-Reply-To: <20200428040433.23504-13-jandryuk@gmail.com> References: <20200428040433.23504-1-jandryuk@gmail.com> <20200428040433.23504-13-jandryuk@gmail.com> X-Mailer: VM 8.2.0b under 24.5.1 (i686-pc-linux-gnu) X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Anthony Perard , "xen-devel@lists.xenproject.org" , Marek =?iso-8859-1?Q?Marczykowski-G=F3recki?= , Wei Liu Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Jason Andryuk writes ("[PATCH v5 12/21] libxl: use vchan for QMP access with Linux stubdomain"): > From: Marek Marczykowski-Górecki > > Access to QMP of QEMU in Linux stubdomain is possible over vchan > connection. Handle the actual vchan connection in a separate process > (vchan-socket-proxy). This simplified integration with QMP (already > quite complex), but also allows preliminary filtering of (potentially > malicious) QMP input. > Since only one client can be connected to vchan server at the same time > and it is not enforced by the libxenvchan itself, additional client-side > locking is needed. It is implicitly implemented by vchan-socket-proxy, > as it handle only one connection at a time. Note that qemu supports only > one simultaneous client on a control socket anyway (but in UNIX socket > case, it enforce it server-side), so it doesn't add any extra > limitation. You might mention in your commit message libxl qmp client code already has locking to avoid attempts to talk concurrently to the same qemu. Acked-by: Ian Jackson Thanks, Ian.