Am 30.06.2011 16:16, schrieb Stefano Stabellini:
> On Thu, 30 Jun 2011, Kevin Wolf wrote:
>>> +static int pci_piix3_xen_ide_unplug(DeviceState *dev)
>>> +{
>>> + PCIDevice *pci_dev;
>>> + PCIIDEState *pci_ide;
>>> + DriveInfo *di;
>>> + int i = 0;
>>> +
>>> + pci_dev = DO_UPCAST(PCIDevice, qdev, dev);
>>> + pci_ide = DO_UPCAST(PCIIDEState, dev, pci_dev);
>>> +
>>> + for (; i < 3; i++) {
>>> + di = drive_get_by_index(IF_IDE, i);
>>> + if (di != NULL && di->bdrv != NULL && !di->bdrv->removable) {
>>> + DeviceState *ds = bdrv_get_attached(di->bdrv);
>>> + if (ds) {
>>> + bdrv_detach(di->bdrv, ds);
>>> + }
>>> + bdrv_close(di->bdrv);
>>> + pci_ide->bus[di->bus].ifs[di->unit].bs = NULL;
>>
>> Have you tested if this is enough if the guest tries to continue using
>> the device? I don't know of any case where it's not sufficient, just
>> trying to make sure that it's really true in practice.
>
> The purpose of this is to "hide" the disk from the guest. The unplug is
> supposed to happen *before* the guest enumerates the IDE disks; it is
> responsibility of the guest to make sure of it.
> I tested it with Linux PV on HVM drivers, and Linux doesn't see the
> emulated disk after the unplug, as it should be.
Yeah. What I meant is that we should make sure that a misbehaving guest,
which just keeps on playing with the IDE ports anyway, can't crash qemu.
A quick review suggests that it is the case, but testing it anyway would
be better.
>>> + drive_put_ref(di);
>>> + }
>>> + }
>>> + qdev_reset_all(&(pci_ide->dev.qdev));
>>> + return 0;
>>> +}
>>> +
>>> +PCIDevice *pci_piix3_xen_ide_init(PCIBus *bus, DriveInfo **hd_table, int
>>> devfn)
>>> +{
>>> + PCIDevice *dev;
>>> +
>>> + dev = pci_create_simple(bus, devfn, "piix3-ide-xen");
>>> + dev->qdev.info->unplug = pci_piix3_xen_ide_unplug;
>>
>> Can't this be moved into the PCIDeviceInfo now that we have a separate
>> one for Xen?
>
> No because it would be overridden by the default pci unplug function,
> that is not what we want in this case.
Okay. I'm not familiar with that code, so I'll just trust you there.
Kevin
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
Home