From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:39464) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T7ODL-000342-Bb for qemu-devel@nongnu.org; Fri, 31 Aug 2012 06:12:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T7ODF-0004M9-Fq for qemu-devel@nongnu.org; Fri, 31 Aug 2012 06:12:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1618) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T7ODF-0004M4-6B for qemu-devel@nongnu.org; Fri, 31 Aug 2012 06:12:29 -0400 Message-ID: <50408E06.1070009@redhat.com> Date: Fri, 31 Aug 2012 12:12:22 +0200 From: Kevin Wolf MIME-Version: 1.0 References: <201208232109.q7NL9P9t016424@int-mx09.intmail.prod.int.phx2.redhat.com> In-Reply-To: <201208232109.q7NL9P9t016424@int-mx09.intmail.prod.int.phx2.redhat.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit 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: Jason Baron Cc: aliguori@us.ibm.com, mst@redhat.com, jan.kiszka@siemens.com, qemu-devel@nongnu.org, agraf@suse.de, yamahata@valinux.co.jp, alex.williamson@redhat.com, pbonzini@redhat.com, lcapitulino@redhat.com, afaerber@suse.de, armbru@redhat.com Am 23.08.2012 23:09, schrieb Jason Baron: > 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. > > Signed-off-by: Jason Baron > --- > hw/ide/ahci.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c > index 9fe89a5..06c236f 100644 > --- a/hw/ide/ahci.c > +++ b/hw/ide/ahci.c > @@ -1199,6 +1199,7 @@ void ahci_reset(AHCIState *s) > pr->irq_stat = 0; > pr->irq_mask = 0; > pr->scr_ctl = 0; > + pr->cmd = 0; > ahci_reset_port(s, i); > } > } > In ahci_init() we have: ad->port_regs.cmd = PORT_CMD_SPIN_UP | PORT_CMD_POWER_ON; Why is resetting to 0 in ahci_reset() correct? I think we can still get this part committed for 1.2 after you either explain why 0 is right or send a fixed version. I think for 1.3 there's still a bit more left. We're missing some more fields in a reset: tfdata isn't set at all, should be set to 0x7f in ahci_reset_port(), and cmd_issue should be set to 0. And shouldn't ahci_init() actually call ahci_reset() in order to ensure consistent results? Kevin