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[92.178.7.112]) by smtp.gmail.com with UTF8SMTPSA id 5b1f17b1804b1-459c58ececdsm88196085e9.1.2025.08.06.06.48.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 Aug 2025 06:48:37 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 0e1d7268-72cc-11f0-b898-0df219b8e170 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=google; t=1754488118; x=1755092918; darn=lists.xenproject.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=pwjYNfrhNxwfvUl3nWgGhrOpkF7qtjSx02o5Z/rAA9A=; b=MnjziP2HkCxNft/Zahor97mpYEVAd3shgFcoWfDLSwpjJye+DMvB3i2XLuuk0qP5XA Mf1sSmWPA/laA2JFtB0TVhuxl99XQlU11VhOT1xPI2nv01IU1ebgU1BGFyn9kw44SHBd 9Wj3/ATw+6m76kRVfm7i4RQV+HdJgz4/nYDjk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1754488118; x=1755092918; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=pwjYNfrhNxwfvUl3nWgGhrOpkF7qtjSx02o5Z/rAA9A=; b=SfMzwFlpzQoGyeaoflNivtpJjkLVQ0uvngSnxx+5Swf3kogz6igdMohxq3VTh8vLJl TP/Dm31M1N48JjYH/Y4LpeE/f05BOxhuMdDj+oGZW2sldanZUMY3IyoCNf1tDv3VryD0 0e0EYh0P9Pf9XVokpk0DKtm9PGDM+hXddtaC83YugCNPg5FeJDkU70urV36cykh1C9W1 fJ33rU2LKC5dMrGHNiUDdhAbLjvh6RpJIAyPtrB1zAbaz9xcZqrHLiHI5qe5Odw4V6U9 7972hhBWG+f/ENtNpPIgHqq4tU0JRGIWl/KxvYcGJYeXeogvv+Zeans8UH5NdEBUgVwU MkXg== X-Gm-Message-State: AOJu0YzMmL/qOrV/p2zBR8gLQJZ0YLYrSOovWGu+qnNzl4ps22SsnOcJ 1H/IfCspFZ4FsSnscPCU6YEBxHcSWuDp16HSSTBhUtNqmA1f/FTERBdNg3kZwKWoV7s= X-Gm-Gg: ASbGncvXTGCdW4r2losHNrER6w+8YwpZh6CeQ6nt+gLmgfT8jGDUgGS3gvktSOR0Be0 PNyy/ojyad8W6hxML55w6+97L1nYMDXcRkV2Bpu+8JZZHNu3evfgignPwlff7CKTvsI9MpSM23P jfwDyPWiv/BohGq3mJ38j7MAkeF3uOxCXkg2vYFrQx9z4CI2safH6yfOkvgPM1pvVYhFbpmwt4x U2UbYFYbduOLJKtwHITRUw3V3sf39TxbFBZfv0CSd5+uoA6SePnWuM4/kWRTw96Fu33Qxd2jh0E ifqGdyqMEfQD2scY26d49zRKtEk/5EK/8kpbGOg8GkaePFnBw7XXtslqmeMwZrk5G3/Q2HvCzGz 3X9egnBHek4HsOfTARvDtYsSUTYFxxhqS02qxVZT74A5omXao3rpO+gVSZCcJrmqegQ== X-Google-Smtp-Source: AGHT+IF4sPMyKHriRBNm45A6/0pKloHFhM/OWo8S3I4qwk63PSXoQzdRgCN/2HXKYVVJlX3IEBOckA== X-Received: by 2002:a05:6000:4387:b0:3b7:78c8:937f with SMTP id ffacd0b85a97d-3b8f4197fe9mr2324736f8f.20.1754488117922; Wed, 06 Aug 2025 06:48:37 -0700 (PDT) Date: Wed, 6 Aug 2025 15:48:36 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: dmkhn@proton.me Cc: xen-devel@lists.xenproject.org, andrew.cooper3@citrix.com, anthony.perard@vates.tech, jbeulich@suse.com, julien@xen.org, michal.orzel@amd.com, sstabellini@kernel.org, dmukhin@ford.com Subject: Re: [PATCH v4 0/8] x86: introduce NS16550-compatible UART emulator Message-ID: References: <20250731192130.3948419-1-dmukhin@ford.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250731192130.3948419-1-dmukhin@ford.com> On Thu, Jul 31, 2025 at 07:21:37PM +0000, dmkhn@proton.me wrote: > x86 port of Xen lacks vUART facility similar to Arm's vpl011 to support x86 > guest OS bring up in the embedded setups. > > This patch series introduces initial in-hypervisor emulator for > NS8250/NS16x50-compatible UARTs under CONFIG_VUART_NS16550. > > In parallel domain creation scenario (hyperlaunch), NS16550 emulator helps > early guest firmware and OS bringup debugging, because it eliminates > dependency on the external emulator (qemu) being operational by the time > domains are created. > > The emulator also allows to forward the physical console input to the x86 > domain which is useful when a system has only one physical UART for early > debugging and this UART is owned by Xen. > > By default, CONFIG_VUART_NS16550 enables emulation of NS16550 at I/O port > 0x3f8, IRQ#4 in guest OS (legacy COM1). But all legacy COM resources can be > selected at built-time (no per-domain configuration yet). > > The NS16550 emulator is disabled in default x86 configuration and goes under > CONFIG_EXPERT in menuconfig. > > Limitations > =========== > - Only x86; > - Only HVM domains support (build-time), PVH domains are not supported yet; I'm confused by the above statement, HVM domains always have an emulated serial provided by QEMU if needed, so I think you got this backwards, and it should instead be: - Only PVH domains supported, PV and HVM domains are not supported yet. ? Thanks, Roger.