From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:56264) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T7AuA-0006cH-Bv for qemu-devel@nongnu.org; Thu, 30 Aug 2012 15:59:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T7Au0-0003lB-Q1 for qemu-devel@nongnu.org; Thu, 30 Aug 2012 15:59:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36567) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T7Au0-0003kx-HE for qemu-devel@nongnu.org; Thu, 30 Aug 2012 15:59:44 -0400 Date: Thu, 30 Aug 2012 15:59:42 -0400 From: Jason Baron Message-ID: <20120830195941.GA5313@redhat.com> References: <201208232109.q7NL9P9t016424@int-mx09.intmail.prod.int.phx2.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] [PATCH] ahci: properly reset PxCMD on HBA reset List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf Cc: kwolf@redhat.com, aliguori@us.ibm.com, mst@redhat.com, jan.kiszka@siemens.com, qemu-devel@nongnu.org, armbru@redhat.com, yamahata@valinux.co.jp, alex.williamson@redhat.com, pbonzini@redhat.com, lcapitulino@redhat.com, afaerber@suse.de On Fri, Aug 24, 2012 at 06:39:02AM +0200, Alexander Graf wrote: > > While testing q35, I found that windows 7 (specifically, windows 7 ultimate > > with sp1 x64), wouldn't install because it can't find the cdrom or disk drive. > > The failure message is: 'A required cd/dvd device driver is missing. If you > > have a driver floppy disk, CD, DVD, or USB flash drive, please insert it now.' > > This can also be reproduced on piix by adding an ahci controller, and > > observing that windows 7 does not see any devices behind it. > > > > The problem is that when windows issues a HBA reset, qemu does not reset the > > individual ports' PxCMD register. Windows 7 then reads back the PxCMD register > > and presumably assumes that the ahci controller has already been initialized. > > Windows then never sets up the PxIE register to enable interrupts, and thus it > > never gets irqs back when it sends ata device inquiry commands. > > > > I believe this change brings qemu into ahci 1.3 specification compliance. > > > > Section 10.4.3 HBA Reset: > > > > " > > When GHC.HR is set to '1', GHC.AE, GHC.IE, the IS register, and all port > > register fields (except PxFB/PxFBU/PxCLB/PxCLBU) that are not HwInit in the > > HBA's register memory space are reset. > > " > > > > I've also re-tested Fedora 16 and 17 to verify that they continue to work with > > this change. > > What a nasty little bug. If it makes it work for you, the change is all fine from my POV (and should go into 1.2). > Ok, I don't see it 1.2.0-rc2. If others are ok with this for 1.2, whose tree should this go through? Thanks, -Jason