On Tue, Sep 28, 2010 at 08:01:15AM +0900, Isaku Yamahata wrote: > On Mon, Sep 27, 2010 at 12:40:12PM +0200, Michael S. Tsirkin wrote: > > On Mon, Sep 27, 2010 at 03:22:43PM +0900, Isaku Yamahata wrote: > > > On Sun, Sep 26, 2010 at 02:50:42PM +0200, Michael S. Tsirkin wrote: > > > > On Fri, Sep 24, 2010 at 02:38:09PM +0900, Isaku Yamahata wrote: > > > > > On Wed, Sep 22, 2010 at 01:25:59PM +0200, Michael S. Tsirkin wrote: > > > > > > > > > > > > +PCIESlot *pcie_root_init(PCIBus *bus, int devfn, bool > > > > > > > multifunction, > > > > > > > + const char *bus_name, pci_map_irq_fn > > > > > > > map_irq, > > > > > > > + uint8_t port, uint8_t chassis, uint16_t > > > > > > > slot); > > > > > > > + > > > > > > > > > > > > I am a bit unhappy about all these _init functions. > > > > > > Can devices be created with qdev? If they were > > > > > > it would be possible to configure the system completely > > > > > > from qemu command line. > > > > > > > > > > That's very reasonable question. > > > > > Once machine configuration file is supported, those initialization > > > > > functions will go away. > > > > > I.e. when the initialization code like pc_init1() in pc_piix.c > > > > > disappears, > > > > > those functions will also go away. > > > > > > > > > > Until that, those initialization glues will stay like pci_create > > > > > family > > > > > or other many initialization glues unfortunately. > > > > > This is the result of qdev missing a feature, not the cause. > > > > > It would be a long-term issue to add machine configuration file > > > > > support. > > > > > > > > Just to clarify, if I wanted to have a flag to make virtio-net > > > > a pci express device, how would I do this? > > > > > > the following preparation is needed. > > > - register PCIDeviceInfo with name like "virtio-net-pci-xen" > > > with PCIDeviceInfo::is_express = true. > > > - in initialization function, initialize express capability. > > > - in write config function, call related function. > > > > > > And then, > > > if (express) > > > create "virtio-net-pci-xen" > > > else > > > create "virtio-net-pci" > > > > Sounds pretty bad: we can't double the number of devices > > with each capability we add. > > Can we make it so setting is_express on command line > > will convert the device to PCI express? > > I don't see your point. Capability isn't something that should be > genericly customizable. > If any, it would not be a generic option, but one specific to device. > There is no generic way to automatically convert pci device into > express device. It means designing a new express device. > Maybe what you want is > - set is_express = true > This result in always allocating 4k-sized configuration space. > (Possibly we need more fine-grained parameter in PCIDeviceInfo > than is_express.) > - introduce device specific property that a user can turn on/off > - In initialization function/config write function and where necessary, > check the property.
I think what I want is (At some point) automatically convert all virtio users to express devices, but have a fallback option for old machine types. > -- > yamahata
