On Thu, Mar 24, 2016 at 04:54:33PM -0600, Alex Williamson wrote: > On Wed, 23 Mar 2016 18:12:02 +0800 > Cao jin <caoj.f...@cn.fujitsu.com> wrote: > > > From: Chen Fan <chen.fan.f...@cn.fujitsu.com> > > > > PCI hotplug requires that function 0 is added last to close the > > slot. Since vfio supporting AER, we require that the VM bus > > contains the same set of devices as the host bus to support AER, > > we can perform an AER validation test whenever a function 0 in > > the VM is hot-added. > > > > Signed-off-by: Chen Fan <chen.fan.f...@cn.fujitsu.com> > > --- > > hw/pci/pci.c | 32 ++++++++++++++++++++++++++++++++ > > include/hw/pci/pci.h | 1 + > > 2 files changed, 33 insertions(+) > > > This would of course need Michael's ack. > > Michael, we can't do this in vfio-pci code because we can't guarantee > that function 0 is a vfio-pci device. That would allow users to bypass > our configuration requirements by putting any random non-vfio-pci > device at function 0 of a hot-added multifunction device.
I got that. What I don't understand is how is the non hotplug variant handled, given that is_valid_func is not called in that case. Also, why does it scan all devices on bus, not all functions of the device? > > > > diff --git a/hw/pci/pci.c b/hw/pci/pci.c > > index e67664d..2a5291a 100644 > > --- a/hw/pci/pci.c > > +++ b/hw/pci/pci.c > > @@ -1840,6 +1840,22 @@ PCIDevice *pci_find_device(PCIBus *bus, int bus_num, > > uint8_t devfn) > > return bus->devices[devfn]; > > } > > > > +static void pci_function_is_valid(PCIBus *bus, PCIDevice *d, void *opaque) > > +{ > > + PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(d); > > + Error **errp = opaque; > > + > > + if (*errp) { > > + return; > > + } > > + > > + if (!pc->is_valid_func) { > > + return; > > + } > > + > > + pc->is_valid_func(d, errp); > > +} > > + > > static void pci_qdev_realize(DeviceState *qdev, Error **errp) > > { > > PCIDevice *pci_dev = (PCIDevice *)qdev; > > @@ -1882,6 +1898,22 @@ static void pci_qdev_realize(DeviceState *qdev, > > Error **errp) > > pci_qdev_unrealize(DEVICE(pci_dev), NULL); > > return; > > } > > + > > + /* > > + * If the function number is 0, indicate the closure of the slot. > > + * then we get the chance to check all functions on same device > > + * if valid. > > + */ > > + if (DEVICE(pci_dev)->hotplugged && > > + pci_get_function_0(pci_dev) == pci_dev) { > > + pci_for_each_device(bus, pci_bus_num(bus), > > + pci_function_is_valid, &local_err); > > + if (local_err) { > > + error_propagate(errp, local_err); > > + pci_qdev_unrealize(DEVICE(pci_dev), NULL); > > + return; > > + } > > + } > > } > > > > static void pci_default_realize(PCIDevice *dev, Error **errp) > > diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h > > index 0be07c8..4a2f7d4 100644 > > --- a/include/hw/pci/pci.h > > +++ b/include/hw/pci/pci.h > > @@ -190,6 +190,7 @@ typedef struct PCIDeviceClass { > > > > void (*realize)(PCIDevice *dev, Error **errp); > > int (*init)(PCIDevice *dev);/* TODO convert to realize() and remove */ > > + void (*is_valid_func)(PCIDevice *dev, Error **errp); > > PCIUnregisterFunc *exit; > > PCIConfigReadFunc *config_read; > > PCIConfigWriteFunc *config_write;