From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:39992) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T8zTt-0001iX-F4 for qemu-devel@nongnu.org; Tue, 04 Sep 2012 16:12:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T8zTp-0006gp-1M for qemu-devel@nongnu.org; Tue, 04 Sep 2012 16:12:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:7604) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T8zTo-0006gj-Oy for qemu-devel@nongnu.org; Tue, 04 Sep 2012 16:12:12 -0400 Date: Tue, 4 Sep 2012 16:12:10 -0400 From: Jason Baron Message-ID: <20120904201210.GB22890@redhat.com> References: <201208232109.q7NL9P9t016424@int-mx09.intmail.prod.int.phx2.redhat.com> <50408E06.1070009@redhat.com> <20120831142305.GA12212@redhat.com> <128F51EA-270A-41FA-A284-530EB6599C41@suse.de> <20120831191507.GG12212@redhat.com> <20120831205417.GI12212@redhat.com> <8C50A492-161D-439A-984D-AADF9DF9CEF4@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8C50A492-161D-439A-984D-AADF9DF9CEF4@suse.de> 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: Kevin Wolf , "aliguori@us.ibm.com" , "mst@redhat.com" , "jan.kiszka@siemens.com" , "qemu-devel@nongnu.org" , "lcapitulino@redhat.com" , "yamahata@valinux.co.jp" , "alex.williamson@redhat.com" , "pbonzini@redhat.com" , "afaerber@suse.de" , "armbru@redhat.com" On Fri, Aug 31, 2012 at 11:25:52PM -0700, Alexander Graf wrote: > On 31.08.2012, at 13:54, Jason Baron wrote: > > > On Fri, Aug 31, 2012 at 01:29:46PM -0700, Alexander Graf wrote: > >> On 31.08.2012, at 12:15, Jason Baron wrote: > >> > >>> On Fri, Aug 31, 2012 at 12:04:59PM -0700, Alexander Graf wrote: > >>>> On 31.08.2012, at 07:23, Jason Baron wrote: > >>>> > >>>>> On Fri, Aug 31, 2012 at 12:12:22PM +0200, Kevin Wolf wrote: > >>>>>> 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. > >>>>>> > >>>>> > >>>>> Good catch. I just tried out the following instead in ahci_reset(): > >>>>> > >>>>> pr->cmd = PORT_CMD_SPIN_UP | PORT_CMD_POWER_ON; > >>>>> > >>>>> And it continues to make Windows7 find the ahci disks. I'd like to do a > >>>>> little more testing, but I will send an updated path. > >>>> > >>>> Since we reset on init, we can just shove it there completely, right? > >>>> > >>>> > >>> > >>> Actually, we don't call reset on init. I'm thinking for 1.2, we can just > >>> add the fix to the reset path, and as Kevin suggested in 1.3, we will > >>> look to add a call to ahci_reset() in the init path. > >> > >> We register the reset handler as generic reset path, no? It should be called on machine init then. Every reset handler gets called on machine boot. > >> > > > > what about hotplug? There we call init, but not reset? > > Really? It would be broken then already, no? > Yes, you are right - hotplug calls reset. I've thus dropped the clear from the init path. Please see my v2 posting. Thanks, -Jason