From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48707) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YxXlA-0001QI-0a for qemu-devel@nongnu.org; Wed, 27 May 2015 05:36:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YxXl6-0000vC-PU for qemu-devel@nongnu.org; Wed, 27 May 2015 05:36:23 -0400 Received: from mail-wi0-f173.google.com ([209.85.212.173]:33024) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YxXl6-0000uc-Jc for qemu-devel@nongnu.org; Wed, 27 May 2015 05:36:20 -0400 Received: by wicmx19 with SMTP id mx19so87879963wic.0 for ; Wed, 27 May 2015 02:36:19 -0700 (PDT) Message-ID: <55659010.6010302@cloudius-systems.com> Date: Wed, 27 May 2015 12:36:16 +0300 From: Avi Kivity MIME-Version: 1.0 References: <555DE2EF.1000509@redhat.com> <20150522110136.GF14428@redhat.com> <20150522111259.GG14428@redhat.com> <55631B3A.7080803@redhat.com> <5564E4C9.8010906@codeaurora.org> <55658EAB.3010107@redhat.com> In-Reply-To: <55658EAB.3010107@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Announcing qboot, a minimal x86 firmware for QEMU List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , Christopher Covington , "Daniel P. Berrange" , Peter Maydell Cc: qemu-devel , KVM list On 05/27/2015 12:30 PM, Paolo Bonzini wrote: > > On 26/05/2015 23:25, Christopher Covington wrote: >> On 05/25/2015 08:53 AM, Paolo Bonzini wrote: >>> On 22/05/2015 13:12, Daniel P. Berrange wrote: >>>> In >>>> particular I don't see why we need to have a SATA controller and ISA/LPC >>>> bridge in every virt machine - root PCI bus only should be possible, as you >>>> can provide disks via virtio-blk or virtio-scsi and serial, parallel, mouse, >>>> floppy via PCI devices and/or by adding a USB bus in the cases where you >>>> really need one. >>> I think removing the ISA/LPC bridge is hard. It includes the real-time >>> clock and fw_cfg, for example. >> Could VirtIO specified replacements make sense for these peripherals? > Not really. virtio is too heavyweight and you'd be reinventing the > wheel unnecessarily. > > For example, ARM's "-M virt" uses a pl011 block for the RTC, and also > uses fw_cfg. Another commonly used ISA device is the UART, for which > again -M virt uses a pl031. > The RTC can be replaced by kvmclock, the keyboard by virtio-console. Maybe we can provide an msr- or pci- based interface to fw_cfg.