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Re: [Qemu-devel] [PATCH V3 0/4] vfio: Introduce Live migration capabilit
From: |
Kirti Wankhede |
Subject: |
Re: [Qemu-devel] [PATCH V3 0/4] vfio: Introduce Live migration capability to vfio_mdev device |
Date: |
Mon, 5 Mar 2018 18:32:56 +0530 |
Hi Yulei Zhang,
This series is same as the previous version, that is, there is no
pre-copy phase. This only takes care of stop-and-copy phase.
As per we discussed in KVM Forum 2017 in October, there should be
provision of pre-copy phase.
Thanks,
Kirti
On 3/5/2018 11:30 AM, Yulei Zhang wrote:
> Summary
>
> This series RFC would like to resume the discussion about how to
> introduce the live migration capability to vfio mdev device.
>
> By adding a new vfio subtype region VFIO_REGION_SUBTYPE_DEVICE_STATE,
> the mdev device will be set to migratable if the new region exist
> during the initialization.
>
> The intention to add the new region is using it for mdev device status
> save and restore during the migration. The access to this region
> will be trapped and forward to the mdev device driver, it also uses
> the first byte in the new region to control the running state of mdev
> device, so during the migration after stop the mdev driver, qemu could
> retrieve the specific device status from this region and transfer to
> the target VM side for the mdev device restore.
>
> In addition, we add one new ioctl VFIO_IOMMU_GET_DIRTY_BITMAP to help do
> the mdev device dirty page synchronization during the migration, currently
> it is just for static copy, in the future we would like to add new interface
> for the pre-copy.
>
> Below is the vfio_mdev device migration sequence
> Source VM side:
> start migration
> |
> V
> get the cpu state change callback, write to the
> subregion's first byte to stop the mdev device
> |
> V
> quary the dirty page bitmap from iommu container
> and add into qemu dirty list for synchronization
> |
> V
> save the deivce status into Qemufile which is
> read from the vfio device subregion
>
> Target VM side:
> restore the mdev device after get the
> saved status context from Qemufile
> |
> V
> get the cpu state change callback
> write to subregion's first byte to
> start the mdev device to put it in
> running status
> |
> V
> finish migration
>
> V3->V2:
> 1. rebase the patch to Qemu stable 2.10 branch.
> 2. use a common name for the subregion instead of specific for
> intel IGD.
>
> V1->V2:
> Per Alex's suggestion:
> 1. use device subtype region instead of VFIO PCI fixed region.
> 2. remove unnecessary ioctl, use the first byte of subregion to
> control the running state of mdev device.
> 3. for dirty page synchronization, implement the interface with
> VFIOContainer instead of vfio pci device.
>
> Yulei Zhang (4):
> vfio: introduce a new VFIO subregion for mdev device migration support
> vfio: Add vm status change callback to stop/restart the mdev device
> vfio: Add struct vfio_vmstate_info to introduce put/get callback
> funtion for vfio device status save/restore
> vifo: introduce new VFIO ioctl VFIO_IOMMU_GET_DIRTY_BITMAP
>
> hw/vfio/common.c | 34 +++++++++
> hw/vfio/pci.c | 171
> +++++++++++++++++++++++++++++++++++++++++-
> hw/vfio/pci.h | 1 +
> include/hw/vfio/vfio-common.h | 1 +
> linux-headers/linux/vfio.h | 29 ++++++-
> 5 files changed, 232 insertions(+), 4 deletions(-)
>
- [Qemu-devel] [PATCH V3 0/4] vfio: Introduce Live migration capability to vfio_mdev device, Yulei Zhang, 2018/03/05
- [Qemu-devel] [PATCH V3 2/4] vfio: Add vm status change callback to stop/restart the mdev device, Yulei Zhang, 2018/03/05
- [Qemu-devel] [PATCH V3 1/4] vfio: introduce a new VFIO subregion for mdev device migration support, Yulei Zhang, 2018/03/05
- [Qemu-devel] [PATCH V3 3/4] vfio: Add struct vfio_vmstate_info to introduce put/get callback funtion for vfio device status save/restore, Yulei Zhang, 2018/03/05
- [Qemu-devel] [PATCH V3 4/4] vifo: introduce new VFIO ioctl VFIO_IOMMU_GET_DIRTY_BITMAP, Yulei Zhang, 2018/03/05
- Re: [Qemu-devel] [PATCH V3 0/4] vfio: Introduce Live migration capability to vfio_mdev device, no-reply, 2018/03/05
- Re: [Qemu-devel] [PATCH V3 0/4] vfio: Introduce Live migration capability to vfio_mdev device,
Kirti Wankhede <=
- Re: [Qemu-devel] [PATCH V3 0/4] vfio: Introduce Live migration capability to vfio_mdev device, Alex Williamson, 2018/03/12