[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [virtio-dev] Re: [PATCH v2 0/4] Use of unique identifie
From: |
Venu Busireddy |
Subject: |
Re: [Qemu-devel] [virtio-dev] Re: [PATCH v2 0/4] Use of unique identifier for pairing virtio and passthrough devices... |
Date: |
Tue, 26 Jun 2018 23:12:56 -0500 |
User-agent: |
Mutt/1.9.2 (2017-12-15) |
On 2018-06-27 07:06:42 +0300, Michael S. Tsirkin wrote:
> On Tue, Jun 26, 2018 at 10:49:30PM -0500, Venu Busireddy wrote:
> > The patch set "Enable virtio_net to act as a standby for a passthru
> > device" [1] deals with live migration of guests that use passthrough
> > devices. However, that scheme uses the MAC address for pairing
> > the virtio device and the passthrough device. The thread "netvsc:
> > refactor notifier/event handling code to use the failover framework"
> > [2] discusses an alternate mechanism, such as using an UUID, for pairing
> > the devices. Based on that discussion, proposals "Add "Group Identifier"
> > to virtio PCI capabilities." [3] and "RFC: Use of bridge devices to
> > store pairing information..." [4] were made.
> >
> > The current patch set includes all the feedback received for proposals [3]
> > and [4]. For the sake of completeness, patch for the virtio specification
> > is also included here. Following is the updated proposal.
> >
> > 1. Extend the virtio specification to include a new virtio PCI capability
> > "VIRTIO_PCI_CAP_GROUP_ID_CFG".
>
> There's still discussion around whether it should be
> a virtio pci capability, a virtio net config field or
> a new kind of capability.
>
> > 2. Enhance the QEMU CLI to include a "uuid" option to the virtio device.
> > The "uuid" is a string in UUID format.
> >
> > 3. Enhance the QEMU CLI to include a "uuid" option to the bridge device.
> > The "uuid" is a string in UUID format. Currently, PCIe bridge for
> > the Q35 model is supported.
> >
> > 4. The operator creates a unique identifier string using 'uuidgen'.
> >
> > 5. When the virtio device is created, the operator uses the "uuid" option
> > (for example, '-device virtio-net-pci,uuid="string"') and specifies
> > the UUID created in step 4.
> >
> > QEMU stores the UUID in the virtio device's configuration space
> > in the capability "VIRTIO_PCI_CAP_GROUP_ID_CFG".
> >
> > 6. When assigning a PCI device to the guest in passthrough mode, the
> > operator first creates a bridge using the "uuid" option (for example,
> > '-device pcie-downstream,uuid="string"') to specify the UUID created
> > in step 4, and then attaches the passthrough device to the bridge.
> >
> > QEMU stores the UUID in the configuration space of the bridge as
> > Vendor-Specific capability (0x09). The "Vendor" here is not to be
> > confused with a specific organization. Instead, the vendor of the
> > bridge is QEMU. To avoid mixing up with other bridges, the bridge
> > will be created with vendor ID 0x1b36 (PCI_VENDOR_ID_REDHAT) and
> > device ID 0x000e (PCI_DEVICE_ID_REDHAT_PCIE_BRIDGE) if the "uuid"
> > option is specified. Otherwise, current defaults are used.
> >
> > 7. Patch 4 in patch series "Enable virtio_net to act as a standby for
> > a passthru device" [1] needs to be modified to use the UUID values
> > present in the bridge's configuration space and the virtio device's
> > configuration space instead of the MAC address for pairing the devices.
> >
> > Thanks!
> >
> > Venu
>
> The part where the visibility of a vfio device is controlled by the
> virtio driver acknowledging the backup feature is missing here.
Could you please elaborate?
Thanks,
Venu
>
>
> > [1] https://lists.oasis-open.org/archives/virtio-dev/201805/msg00156.html
> > [2] https://www.spinics.net/lists/netdev/msg499011.html
> > [3] https://lists.oasis-open.org/archives/virtio-dev/201805/msg00118.html
> > [4] https://lists.oasis-open.org/archives/virtio-dev/201805/msg00204.html
> >
> > Changes in v2:
> > - As Michael Tsirkin suggested, changed the virtio specification
> > to restrict the group identifier to be a 16-byte field, presented
> > entirely in the virtio device's configuration space.
> > - As Michael Tsirkin suggested, instead of tweaking the ioh3420
> > device with Red Hat vendor ID, create a new PCIe bridge device
> > named "pcie-downstream" with Red Hat Vendor ID, and include the
> > group identifier in this device.
> > - Added a new patch to enhance the "pci-bridge" device to support
> > the group identifier (for the i440FX model).
> >
> > Venu Busireddy (4):
> > Add a true or false option to the DEFINE_PROP_UUID macro.
> > Add "Group Identifier" support to virtio devices.
> > Add "Group Identifier" support to Red Hat PCI bridge.
> > Add "Group Identifier" support to Red Hat PCI Express bridge.
> >
> > default-configs/arm-softmmu.mak | 1 +
> > default-configs/i386-softmmu.mak | 1 +
> > default-configs/x86_64-softmmu.mak | 1 +
> > hw/acpi/vmgenid.c | 2 +-
> > hw/pci-bridge/Makefile.objs | 1 +
> > hw/pci-bridge/pci_bridge_dev.c | 8 +
> > hw/pci-bridge/pcie_downstream.c | 215 ++++++++++++++++++++
> > hw/pci-bridge/pcie_downstream.h | 10 +
> > hw/pci/pci_bridge.c | 26 +++
> > hw/virtio/virtio-pci.c | 15 ++
> > hw/virtio/virtio-pci.h | 3 +-
> > include/hw/pci/pci.h | 3 +
> > include/hw/pci/pcie.h | 1 +
> > include/hw/qdev-properties.h | 4 +-
> > include/standard-headers/linux/virtio_pci.h | 8 +
> > 15 files changed, 295 insertions(+), 4 deletions(-)
> > create mode 100644 hw/pci-bridge/pcie_downstream.c
> > create mode 100644 hw/pci-bridge/pcie_downstream.h
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: address@hidden
> For additional commands, e-mail: address@hidden
>
- [Qemu-devel] [PATCH v2 1/4] Add a true or false option to the DEFINE_PROP_UUID macro., (continued)
[Qemu-devel] [PATCH v2 4/4] Add "Group Identifier" support to Red Hat PCI Express bridge., Venu Busireddy, 2018/06/26
[Qemu-devel] [PATCH v2 virtio 1/1] Add "Group Identifier" to virtio PCI capabilities., Venu Busireddy, 2018/06/26
Re: [Qemu-devel] [PATCH v2 0/4] Use of unique identifier for pairing virtio and passthrough devices..., Michael S. Tsirkin, 2018/06/27
Re: [Qemu-devel] [PATCH v2 0/4] Use of unique identifier for pairing virtio and passthrough devices..., Roman Kagan, 2018/06/27
- Re: [Qemu-devel] [PATCH v2 0/4] Use of unique identifier for pairing virtio and passthrough devices..., Venu Busireddy, 2018/06/27
- Re: [Qemu-devel] [PATCH v2 0/4] Use of unique identifier for pairing virtio and passthrough devices..., Michael S. Tsirkin, 2018/06/27
- Re: [Qemu-devel] [PATCH v2 0/4] Use of unique identifier for pairing virtio and passthrough devices..., Venu Busireddy, 2018/06/27
- Re: [Qemu-devel] [PATCH v2 0/4] Use of unique identifier for pairing virtio and passthrough devices..., Michael S. Tsirkin, 2018/06/27
- Re: [Qemu-devel] [PATCH v2 0/4] Use of unique identifier for pairing virtio and passthrough devices..., Venu Busireddy, 2018/06/27
- Re: [Qemu-devel] [PATCH v2 0/4] Use of unique identifier for pairing virtio and passthrough devices..., Michael S. Tsirkin, 2018/06/27
- Re: [Qemu-devel] [PATCH v2 0/4] Use of unique identifier for pairing virtio and passthrough devices..., Venu Busireddy, 2018/06/27