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Re: [Qemu-devel] [PATCH v3 4/9] ide: Drop redundant IDEState member bs
From: |
Stefano Stabellini |
Subject: |
Re: [Qemu-devel] [PATCH v3 4/9] ide: Drop redundant IDEState member bs |
Date: |
Fri, 7 Feb 2014 12:58:43 +0000 |
User-agent: |
Alpine 2.02 (DEB 1266 2009-07-14) |
On Thu, 6 Feb 2014, Markus Armbruster wrote:
> Stefano Stabellini <address@hidden> writes:
>
> > On Wed, 5 Feb 2014, Markus Armbruster wrote:
> >> [Note cc: Stefano]
> >>
> >> Kevin Wolf <address@hidden> writes:
> >>
> >> > Am 30.01.2014 um 13:16 hat Markus Armbruster geschrieben:
> >> >> It's a copy of dev->conf.bs. The copy was needed for non-qdevified
> >> >> controllers, which lacked dev.
> >> >>
> >> >> Note how pci_piix3_xen_ide_unplug() cleared the copy. We'll get back
> >> >> to that in the next few commits.
> >> >>
> >> >> Signed-off-by: Markus Armbruster <address@hidden>
> >> >
> >> > So this pci_piix3_xen_ide_unplug() is what happens here:
> >> >
> >> >> --- a/hw/ide/piix.c
> >> >> +++ b/hw/ide/piix.c
> >> >> @@ -169,12 +169,9 @@ static int pci_piix_ide_initfn(PCIDevice *dev)
> >> >>
> >> >> static int pci_piix3_xen_ide_unplug(DeviceState *dev)
> >> >> {
> >> >> - PCIIDEState *pci_ide;
> >> >> DriveInfo *di;
> >> >> int i = 0;
> >> >>
> >> >> - pci_ide = PCI_IDE(dev);
> >> >> -
> >> >> for (; i < 3; i++) {
> >> >> di = drive_get_by_index(IF_IDE, i);
> >> >> if (di != NULL && !di->media_cd) {
> >> >> @@ -183,7 +180,6 @@ static int pci_piix3_xen_ide_unplug(DeviceState
> >> >> *dev)
> >> >> bdrv_detach_dev(di->bdrv, ds);
> >> >> }
> >> >> bdrv_close(di->bdrv);
> >> >> - pci_ide->bus[di->bus].ifs[di->unit].bs = NULL;
> >> >> drive_put_ref(di);
> >> >> }
> >> >> }
> >> >
> >> > Probably I'm just missing the obvious, but it seems to me that the
> >> > copy was cleared here, while the original was left around. This was
> >> > no problem because the original was unused anyway after device
> >> > initialisation.
> >> >
> >> > Now that the copy doesn't exist any more, we can't clear it, obviously,
> >> > but why don't we have to clear the original? Won't we still run the
> >> > "device is attached" code branches even though the device is really
> >> > unplugged?
> >>
> >> It's been a while since I wrote this. Almost 14 months, in fact.
> >>
> >> No other IDE controller implements DeviceClass method unplug(). I can't
> >> remember why the normal code to detach the backend (release_drive())
> >> doesn't do here. Stefano, can you help?
> >
> > Too long to be able to remember the exact details :-/
> > However if you point me to a branch I can give it a try and tell you if
> > the unplug still works as it used to.
>
> Series trivially rebased to current master available at
> git://repo.or.cz/qemu/armbru.git branch kill-non-qdev-ide
Unfortunately it doesn't work: I can see both sda and xvda being present
after the system has booted.