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 <jba...@redhat.com> > > --- > > 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. > 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? > Agreed, those all look like good additional cleanups for 1.3. I will add them to my q35 treee for testing. Thanks, -Jason
