Re: [Qemu-devel] [RFC PATCH 3/6] RAMBlock: Add a name field

Alex Williamson
2010-06-09T16:55:54Z

On Wed, 2010-06-09 at 13:18 +0100, Paul Brook wrote:
> > > > Not all ram is associated with a device.
> > >
> > > Maybe not, but where it is we should be using that information.
> > > Absolute minimum we should be using the existing qdev address rather than
> > > inventing a new one. Duplicating this logic inside every device seems
> > > like a bad idea so I suggest identifying ram blocks by a (name, device)
> > > pair. For now we can allow a NULL device for system memory.
> >
> > I'm not sure if this is what you're after, but what if we change it to
> > something like:
> >
> > + snprintf(name, sizeof(name), "%s.%02x.%x.rom-%s",
> > + pdev->bus->qbus.name, PCI_SLOT(pdev->devfn),
> > + PCI_FUNC(pdev->devfn), pdev->qdev.info->name);
> >
> > This gives us things like "pci.0.03.0.rom-rtl8139". For pci-assign, we
> > can expand on the host details, such as:
> > ..
> > Giving us "pci.0.04.0.bar0-pci-assign(0000:01:10.0)". Anywhere closer?
>
> Not really. This identifier is device and bus independent, which is why I
> suggested passing the device to qemu_ram_alloc. This can then figure out how
> to the identify the device. It should probably do this the same way that we
> identify the saved state for the device. Currently I think this is an
> arbitrary vmstate name/id, but I expect this to change to a qdev address
> (e.g. /i440FX-pcihost/pci.0/_addr_04.0").

Ok, that seems fairly reasonable, so from a device pointer we can get
something like "/i440FX-pcihost/pci.0/_addr_04.0", then we can add
something like ":rom" or ":bar.0" to it via an extra string.

qemu_ram_alloc(DeviceState *dev, const char *info, size)

Does a function already exist to print out a qdev address path? I don't
want to guess at something based on only this example. Is there a
reserved/unused character we can use to separate the qdev device string
from the supplied name? Thanks,

Alex