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?
Thanks in advance!
Best Regards
Nan Xiao
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
>
>
>
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