Re: [Xen-devel] [PULL 00/20] acpi,pc,pci fixes and enhancements

["Michael S. Tsirkin" <mst@xxxxxxxxxx>]

On Wed, Feb 19, 2014 at 11:08:25AM +0200, Michael S. Tsirkin wrote:
> On Tue, Feb 18, 2014 at 05:10:00PM +0000, Stefano Stabellini wrote:
> > On Tue, 18 Feb 2014, Paolo Bonzini wrote:
> > > Il 18/02/2014 15:25, Stefano Stabellini ha scritto:
> > > > On Tue, 18 Feb 2014, Paolo Bonzini wrote:
> > > > > Il 18/02/2014 13:45, Stefano Stabellini ha scritto:
> > > > > > Disk unplug: hw/ide/piix.c:pci_piix3_xen_ide_unplug (see the 
> > > > > > beginning
> > > > > > of the email :-P).
> > > > > > It is called by hw/xen/xen_platform.c:platform_fixed_ioport_writew, 
> > > > > > in
> > > > > > response to the guest writing to a magic ioport specifically to 
> > > > > > unplug
> > > > > > the emulated disk.
> > > > > > With this patch after the guest boots I can still access both xvda 
> > > > > > and
> > > > > > sda for the same disk, leading to fs corruptions.
> > > > > 
> > > > > Ok, the last paragraph is what I was missing.
> > > > > 
> > > > > So this is dc->unplug for the PIIX3 IDE device.  Because PCI declares 
> > > > > a
> > > > > hotplug handler, dc->unplug is not called anymore.
> > > > > 
> > > > > But unlike other dc->unplug callbacks, pci_piix3_xen_ide_unplug 
> > > > > doesn't
> > > > > free
> > > > > the device, it just drops the disks underneath.  I think the simplest
> > > > > solution
> > > > > is to _not_ make it a dc->unplug callback at all, and call
> > > > > pci_piix3_xen_ide_unplug from unplug_disks instead of qdev_unplug.
> > > > > qdev_unplug means "ask guest to start unplug", which is not what Xen 
> > > > > wants
> > > > > to
> > > > > do here.
> > > > 
> > > > Yes, you are right, pci_piix3_xen_ide_unplug is not called anymore.
> > > > Calling it directly from unplug_disks fixes the issue:
> > > > 
> > > > 
> > > > ---
> > > > 
> > > > Call pci_piix3_xen_ide_unplug from unplug_disks
> > > > 
> > > > Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> > > > 
> > > > diff --git a/hw/ide/piix.c b/hw/ide/piix.c
> > > > index 0eda301..40757eb 100644
> > > > --- a/hw/ide/piix.c
> > > > +++ b/hw/ide/piix.c
> > > > @@ -167,7 +167,7 @@ static int pci_piix_ide_initfn(PCIDevice *dev)
> > > >      return 0;
> > > >  }
> > > > 
> > > > -static int pci_piix3_xen_ide_unplug(DeviceState *dev)
> > > > +int pci_piix3_xen_ide_unplug(DeviceState *dev)
> > > >  {
> > > >      PCIIDEState *pci_ide;
> > > >      DriveInfo *di;
> > > > @@ -266,7 +266,6 @@ static void piix3_ide_xen_class_init(ObjectClass 
> > > > *klass,
> > > > void *data)
> > > >      k->device_id = PCI_DEVICE_ID_INTEL_82371SB_1;
> > > >      k->class_id = PCI_CLASS_STORAGE_IDE;
> > > >      set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
> > > > -    dc->unplug = pci_piix3_xen_ide_unplug;
> > > >  }
> > > > 
> > > >  static const TypeInfo piix3_ide_xen_info = {
> > > > diff --git a/hw/xen/xen_platform.c b/hw/xen/xen_platform.c
> > > > index 70875e4..1d9d0e9 100644
> > > > --- a/hw/xen/xen_platform.c
> > > > +++ b/hw/xen/xen_platform.c
> > > > @@ -27,6 +27,7 @@
> > > > 
> > > >  #include "hw/hw.h"
> > > >  #include "hw/i386/pc.h"
> > > > +#include "hw/ide.h"
> > > >  #include "hw/pci/pci.h"
> > > >  #include "hw/irq.h"
> > > >  #include "hw/xen/xen_common.h"
> > > > @@ -110,7 +111,7 @@ static void unplug_disks(PCIBus *b, PCIDevice *d, 
> > > > void
> > > > *o)
> > > >      if (pci_get_word(d->config + PCI_CLASS_DEVICE) ==
> > > >              PCI_CLASS_STORAGE_IDE
> > > >              && strcmp(d->name, "xen-pci-passthrough") != 0) {
> > > > -        qdev_unplug(DEVICE(d), NULL);
> > > > +        pci_piix3_xen_ide_unplug(DEVICE(d));
> > > >      }
> > > >  }
> > > > 
> > > > diff --git a/include/hw/ide.h b/include/hw/ide.h
> > > > index 507e6d3..bc8bd32 100644
> > > > --- a/include/hw/ide.h
> > > > +++ b/include/hw/ide.h
> > > > @@ -17,6 +17,7 @@ void pci_cmd646_ide_init(PCIBus *bus, DriveInfo
> > > > **hd_table,
> > > >  PCIDevice *pci_piix3_xen_ide_init(PCIBus *bus, DriveInfo **hd_table, 
> > > > int
> > > > devfn);
> > > >  PCIDevice *pci_piix3_ide_init(PCIBus *bus, DriveInfo **hd_table, int
> > > > devfn);
> > > >  PCIDevice *pci_piix4_ide_init(PCIBus *bus, DriveInfo **hd_table, int
> > > > devfn);
> > > > +int pci_piix3_xen_ide_unplug(DeviceState *dev);
> > > >  void vt82c686b_ide_init(PCIBus *bus, DriveInfo **hd_table, int devfn);
> > > > 
> > > >  /* ide-mmio.c */
> > > > 
> > > 
> > > Acked-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> > 
> > Thanks. Should I send it to Peter via the xen tree or anybody else wants
> > to pick this up?
> 
> I'll rebase my tree on top of this, to avoid bisect failures.

Oh sorry, I noticed what broke this is - is merged already.
Pls merge fix through xen tree then, makes more sense.


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