From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43957) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cg7bw-0000Fp-Mv for qemu-devel@nongnu.org; Tue, 21 Feb 2017 05:23:57 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cg7bs-0004y9-MI for qemu-devel@nongnu.org; Tue, 21 Feb 2017 05:23:56 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:33504) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cg7bs-0004xl-Cd for qemu-devel@nongnu.org; Tue, 21 Feb 2017 05:23:52 -0500 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v1LANWwc012714 for ; Tue, 21 Feb 2017 05:23:50 -0500 Received: from e32.co.us.ibm.com (e32.co.us.ibm.com [32.97.110.150]) by mx0a-001b2d01.pphosted.com with ESMTP id 28rekcc4f2-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 21 Feb 2017 05:23:49 -0500 Received: from localhost by e32.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 21 Feb 2017 03:23:48 -0700 References: <20170220141943.8426-1-cornelia.huck@de.ibm.com> <20170220141943.8426-2-cornelia.huck@de.ibm.com> <967f7397-9995-0d24-bf35-682da2c732ff@redhat.com> From: Christian Borntraeger Date: Tue, 21 Feb 2017 11:23:44 +0100 MIME-Version: 1.0 In-Reply-To: <967f7397-9995-0d24-bf35-682da2c732ff@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Message-Id: <48b23a4f-ebd3-2306-ea0f-75b713817440@de.ibm.com> Subject: Re: [Qemu-devel] [PATCH 1/5] elf-loader: Allow late loading of elf List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth Cc: qemu-devel@nongnu.org, Cornelia Huck , Farhan Ali , Jens Freimann , Viktor Mihajlovski , Alexander Graf On 02/20/2017 04:33 PM, Thomas Huth wrote: > On 20.02.2017 15:19, Cornelia Huck wrote: >> From: Farhan Ali >> >> The current QEMU ROM infrastructure rejects late loading of ROMs. >> And ELFs are currently loaded as ROM, this prevents delayed loading >> of ELFs. So when loading ELF, allow the user to specify if ELF should >> be loaded as ROM or not. >> >> If an ELF is not loaded as ROM, then they are not restored on a >> guest reboot/reset and so its upto the user to handle the reloading. > > Could you maybe also explain here why you need such a delayed ELF > loading? Why can't you load the s390-netboot.img at the same time as > s390-ccw.img? Please read the cover letter for some details how to build such a netrom. This is a simple variant to implement a standard compliant network boot today but using a kernel+busybox+scripts. Long term we certainly want to have a look at implementing something in the ccw bios, but this (tcp stack, virtio net, etc) will take some (a lot?) more time. Having a ramdisk+kernel loaded all the time would be extremely wasteful. This patch (1) has another advantage. Right now we load the ccw bios all the time, even for -kernel xxx boot, to allow the guest user to use chreipl to reboot from a disk. With this in place we can rework our ccw bios loader to load the ccw bios lazily as well. Christian