On Fri, 2015-09-11 at 07:58 +0800, Nan Xiao wrote: > Hi Alex, > > Thanks very much for your response! so for assigning PCI device in QEMU. > The following method is deprecated: > > qemu-system-x86_64 ... -device pci-assign,host=0000:21:00.1 > > I should use this one instead: > > qemu-system-x86_64 ... -device vfio-pci,host=0000:21:00.1 > > right? Yes, and the device needs to be bound to the vfio_pci driver in the host rather than pci-stub (and you may or may not need to care about IOMMU groups[1]). Thanks, Alex [1] http://vfio.blogspot.com/2014/08/iommu-groups-inside-and-out.html > On Thu, Sep 10, 2015 at 11:08 PM, Alex Williamson > <alex.williamson@xxxxxxxxxx> wrote: > > On Thu, 2015-09-10 at 18:22 +0800, Nan Xiao wrote: > >> Hi all, > >> > >> When building kernel, it prompts "CONFIG_KVM_DEVICE_ASSIGNMENT" is "deprecated". > >> But it is still used in kernel code. E.g.: > >> "kvm_vm_ioctl_check_extension" function: > >> { > >> ... > >> #ifdef CONFIG_KVM_DEVICE_ASSIGNMENT > >> case KVM_CAP_ASSIGN_DEV_IRQ: > >> case KVM_CAP_PCI_2_3: > >> #endif > >> r = 1; > >> break; > >> ... > >> #ifdef CONFIG_KVM_DEVICE_ASSIGNMENT > >> case KVM_CAP_IOMMU: > >> r = iommu_present(&pci_bus_type); > >> break; > >> #endif > >> ... > >> } > >> > >> If not configure this option, the following code will execute failed: > >> > >> ret = ioctl(dev, KVM_CHECK_EXTENSION, KVM_CAP_IOMMU); > >> > >> So does it mean to use KVM assigned device feature, the > >> "CONFIG_KVM_DEVICE_ASSIGNMENT" > >> is not "deprecated"? > > > > Legacy KVM device assignment is deprecated, it is fully replaced by > > VFIO-based device assignment. The intention is to deprecate legacy KVM > > device assignment now, so all users can transition away from it and at > > some point remove it from the kernel. When using QEMU and libvirt, the > > default is already to use VFIO instead of legacy KVM device assignment. > > Thanks, > > > > Alex > > > > > > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
