From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50243) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YslyD-0002Bi-Us for qemu-devel@nongnu.org; Thu, 14 May 2015 01:46:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ysly8-00049m-Uf for qemu-devel@nongnu.org; Thu, 14 May 2015 01:46:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45752) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ysly8-000486-NM for qemu-devel@nongnu.org; Thu, 14 May 2015 01:46:04 -0400 Date: Thu, 14 May 2015 07:45:38 +0200 From: "Michael S. Tsirkin" Message-ID: <20150514074330-mutt-send-email-mst@redhat.com> References: <20150513174204.GS23627@redhat.com> <555426C0.9020402@weilnetz.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <555426C0.9020402@weilnetz.de> Subject: Re: [Qemu-devel] [PATCH] Do not emulate a floppy drive when -nodefaults List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Weil Cc: xen-devel@lists.xensource.com, Stefano Stabellini , qemu-devel@nongnu.org, pbonzini@redhat.com, rth@twiddle.net On Thu, May 14, 2015 at 06:38:24AM +0200, Stefan Weil wrote: > Am 13.05.2015 um 20:15 schrieb Stefano Stabellini: > >On Wed, 13 May 2015, Daniel P. Berrange wrote: > >>On Wed, May 13, 2015 at 06:29:46PM +0100, Stefano Stabellini wrote: > >>>Do not emulate a floppy drive if no drives are supposed to be present. > >>> > >>>This fixes the behavior of -nodefaults, that should remove the floppy > >>>drive (see docs/qdev-device-use.txt:Default Devices), but actually > >>>doesn't. > >>Technically that doc is just refering to the disablement of the > >>primary floppy drive, as opposed to the floppy controller. The > >>floppy controller itself is really a built-in device that is > >>defined as part of the machine type, along with the various other > >>platform devices hanging off the PIIX and ISA brige. > >I think you are right, this patch is a bit too harsh in fixing the > >problem: I just wanted to properly disable drive emulation, because from > >my tests the guest thinks that one drive is present even when is not. > > A short test on some of my physical machines shows that most > of them don't have a floppy disk controller at all (dmesg | grep FDC). > > Only some older machines still have one. > > Therefore I think that QEMU must also be able to offer a virtual > machine without an FDC, maybe as the default for the next > version of QEMU. > > Stefan Making it the default in QEMU might break a bunch of existing setups, but IMO it's very reasonable to add such a property, and teach libvirt to set it automatically. -- MST From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH] Do not emulate a floppy drive when -nodefaults Date: Thu, 14 May 2015 07:45:38 +0200 Message-ID: <20150514074330-mutt-send-email-mst@redhat.com> References: <20150513174204.GS23627@redhat.com> <555426C0.9020402@weilnetz.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <555426C0.9020402@weilnetz.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org To: Stefan Weil Cc: xen-devel@lists.xensource.com, Stefano Stabellini , qemu-devel@nongnu.org, pbonzini@redhat.com, rth@twiddle.net List-Id: xen-devel@lists.xenproject.org On Thu, May 14, 2015 at 06:38:24AM +0200, Stefan Weil wrote: > Am 13.05.2015 um 20:15 schrieb Stefano Stabellini: > >On Wed, 13 May 2015, Daniel P. Berrange wrote: > >>On Wed, May 13, 2015 at 06:29:46PM +0100, Stefano Stabellini wrote: > >>>Do not emulate a floppy drive if no drives are supposed to be present. > >>> > >>>This fixes the behavior of -nodefaults, that should remove the floppy > >>>drive (see docs/qdev-device-use.txt:Default Devices), but actually > >>>doesn't. > >>Technically that doc is just refering to the disablement of the > >>primary floppy drive, as opposed to the floppy controller. The > >>floppy controller itself is really a built-in device that is > >>defined as part of the machine type, along with the various other > >>platform devices hanging off the PIIX and ISA brige. > >I think you are right, this patch is a bit too harsh in fixing the > >problem: I just wanted to properly disable drive emulation, because from > >my tests the guest thinks that one drive is present even when is not. > > A short test on some of my physical machines shows that most > of them don't have a floppy disk controller at all (dmesg | grep FDC). > > Only some older machines still have one. > > Therefore I think that QEMU must also be able to offer a virtual > machine without an FDC, maybe as the default for the next > version of QEMU. > > Stefan Making it the default in QEMU might break a bunch of existing setups, but IMO it's very reasonable to add such a property, and teach libvirt to set it automatically. -- MST