[Kimchi-devel] [PATCH v8 0/4] Host device passthrough: Summary
Zhou Zheng Sheng
zhshzhou at linux.vnet.ibm.com
Mon Jul 28 15:25:46 UTC 2014
on 2014/07/28 21:03, Aline Manera wrote:
>
> On 07/28/2014 06:38 AM, Zhou Zheng Sheng wrote:
>> Hi,
>>
>> Yu Xin and me tested the patches on a PC with RHEL6.4 installed. We
>> turned on vt-d in BIOS, enabled intel_iommu=on in kernel command line.
>>
>> After setting this, I verified the IOMMU is enabled.
>> dmesg | grep -e DMAR -e IOMMU | grep -e "DRHD base" -e "enabled"
>>
>> Unfortunately qemu failed to assign PCI devices. The Qemu log was vague.
>> I googled and tried some solutions but none worked. It might be the
>> problem of the machine itself or the maturity of this feature in kernel
>> 2.6 and qemu-kvm 0.12.
>>
>> I also find the libvirt version on RHEL6 is a bit old, it does not
>> provide the necessary device information, so we have to write extra code
>> to fetch it. Moreover, the iommu group sysfs is added in Kenel 3.5, so
>> RHEL6 does not have it.
>>
>> It seems we need more time and work to support RHEL6, so I suggest that,
>> for the first release of this feature, we support the latest Fedora,
>> then in next releases we improve the support for RHEL6.
>
> What about RHEL7, openSUSE 13.1 and Ubuntu 14.04?
>
I didn't get physical machines with this distributions. I did a little
investigation on my Ubuntu 14.04 VM. It supports VFIO, the libvirt is
modern enough to provide all the device information (with only a
one-line-of-code tweak). I didn't actually attach a device to the nested
virtual guest in this Ubuntu virtual machine, because there is no
emulated intel iommu support in QEMU now, but I think it should work in
physical machine because all the necessary parts are ready. I'd try to
find a modern machine with Ubuntu 14.04/RHEL 7 to test this feature.
>> on 2014/07/28 11:01, Zhou Zheng Sheng wrote:
>>> Hi,
>>>
>>> I rebased the patches and send you the drafts for you to test and
>>> develop. I'll add doc and unit tests, then send a formal v9 patch to
>>> list today.
>>>
>>> on 2014/07/25 16:39, Yu Xin Huo wrote:
>>>> Apply failed.
>>>>
>>>>
>>>> On 7/21/2014 5:36 PM, Zhou Zheng Sheng wrote:
>>>>> Hi,
>>>>>
>>>>> This patch series is to enable Kimchi to assign hos devices
>>>>> directly to
>>>>> a VM, thus greately improve VM performance. Currently we support
>>>>> assigning
>>>>> PCI device, USB device and SCSI LUN. For example, we can assign an NIC
>>>>> to VM to improve guest network throughput, or passthrough a USB camera
>>>>> to enable the guest OS to record video.
>>>>>
>>>>> Host devices form a tree. We can assign most of the devices in the
>>>>> tree
>>>>> to VM. By assigning a device, all the devices in its sub-tree are also
>>>>> assigned. It might not make sense to assign a USB controller, because
>>>>> the host may be using one of the devices connected to the controller.
>>>>> Instead, Kimchi just presents the "leaf" devices to assign to guest.
>>>>>
>>>>> In recent Linux kernel and KVM, it is able to recognize the IOMMU
>>>>> group
>>>>> of a PCI device. The "leaf" PCI devices in the same IOMMU group should
>>>>> be assigned and dismissed together. The IOMMU group is the actual
>>>>> smallest isolation granularity of the PCI devices.
>>>>>
>>>>> The first patch is to list all host devices information. It's
>>>>> useful on
>>>>> its own to show host devices information.
>>>>>
>>>>> The second patch is to list all eligible host devices to assign, as
>>>>> well
>>>>> as the "affected" devices in the same IOMMU group.
>>>>>
>>>>> The third patch creates a sub-collection "hostdevs" to the VM
>>>>> resource,
>>>>> and deals with assigning and dismissing devices.
>>>>>
>>>>> The fourth patch adds a sub-collection "vm_holders" to the host device
>>>>> resource. It's to list all VMs that are holding the device.
>>>>>
>>>>> I'll update API and unit test once everyone is happy with the
>>>>> interface
>>>>> and logic.
>>>>>
>>>>> v8:
>>>>> Change the URI for listing affected passthrough devices,
>>>>> suggested by
>>>>> Aline. Move hostdev.py to src/kimchi/model.py. Still discussing
>>>>> API
>>>>> with the front-end developer. Once the API accepted, The author
>>>>> should
>>>>> add tests for model and mockmodel, and change API.md and API.json
>>>>> accordingly.
>>>>> v7:
>>>>> Some minor coding style improvements.
>>>>> v6:
>>>>> Do not passthrough PCI device of class code 0x07. It might
>>>>> contains
>>>>> system device not suitable to assign to guest.
>>>>> v5:
>>>>> Filter ealigible pci devices according to pci class. When
>>>>> assigning a
>>>>> device to VM, check if there are other VMs holding it. Use
>>>>> "kimchi.model.utils.get_vm_config_flag()" to correctly set the device
>>>>> attaching API flag.
>>>>> v4:
>>>>> Add new sub-collection to host device to list the VMs holding
>>>>> the device.
>>>>> v3:
>>>>> Fix a small naming error introduced by rebase.
>>>>> v2:
>>>>> Handle the devices in VM's sub-collection "hostdevs".
>>>>> v1:
>>>>> Handle the devices in VM template.
>>>>>
>>>>> Zhou Zheng Sheng (4):
>>>>> Host device passthrough: List all types of host devices
>>>>> Host device passthrough: List eligible device to passthrough
>>>>> Host device passthrough: Directly assign and dissmis host
>>>>> device from
>>>>> VM
>>>>> Host device passthrough: List VMs that are holding a host device
>>>>>
>>>>> docs/API.md | 11 +-
>>>>> src/kimchi/control/host.py | 7 +
>>>>> src/kimchi/control/vm/hostdevs.py | 44 +++++
>>>>> src/kimchi/featuretests.py | 10 +-
>>>>> src/kimchi/i18n.py | 10 +
>>>>> src/kimchi/mockmodel.py | 7 +-
>>>>> src/kimchi/model/config.py | 2 +
>>>>> src/kimchi/model/host.py | 38 ++--
>>>>> src/kimchi/model/hostdev.py | 311
>>>>> +++++++++++++++++++++++++++++++
>>>>> src/kimchi/model/libvirtstoragepool.py | 18 +-
>>>>> src/kimchi/model/vmhostdevs.py | 324
>>>>> +++++++++++++++++++++++++++++++++
>>>>> src/kimchi/rollbackcontext.py | 3 +
>>>>> src/kimchi/xmlutils.py | 26 ++-
>>>>> tests/test_rest.py | 6 +-
>>>>> tests/test_storagepool.py | 7 +-
>>>>> 15 files changed, 784 insertions(+), 40 deletions(-)
>>>>> create mode 100644 src/kimchi/control/vm/hostdevs.py
>>>>> create mode 100644 src/kimchi/model/hostdev.py
>>>>> create mode 100644 src/kimchi/model/vmhostdevs.py
>>>>>
>>>>
>>>>
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>>>>
>>>
>>
>
--
Zhou Zheng Sheng / 周征晟
E-mail: zhshzhou at linux.vnet.ibm.com
Telephone: 86-10-82454397
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