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Re: [Qemu-devel] [RFC v2 0/2] Add live migration support in the PVRDMA d
Re: [Qemu-devel] [RFC v2 0/2] Add live migration support in the PVRDMA device
Sat, 6 Jul 2019 22:04:55 +0300
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1
On 7/6/19 7:09 AM, Sukrit Bhatnagar wrote:
Changes in v2:
* Modify load_dsr() such that dsr mapping is not performed if dsr value
is non-NULL. Also move free_dsr() out of load_dsr() and call it right
before if needed. These two changes will allow us to call load_dsr()
even when we have already done dsr mapping and would like to go on
with the rest of mappings.
* Use VMStateDescription instead of SaveVMHandlers to describe migration
state. Also add fields for parent PCI object and MSIX.
* Use a temporary structure (struct PVRDMAMigTmp) to hold some fields
during migration. These fields, such as cmd_slot_dma and resp_slot_dma
inside dsr, do not fit into VMSTATE macros as their container
(dsr_info->dsr) will not be ready until it is mapped on the dest.
* Perform mappings to CQ and event notification rings after the state is
loaded. This is an extension to the mappings performed in v1;
following the flow of load_dsr(). All the mappings are succesfully
done on the dest on state load.
Link(s) to v1:
Things working now (were not working at the time of v1):
* vmxnet3 is migrating successfully. The issue was in the migration of
its PCI configuration space, and is solved by the patch Marcel had sent:
* There is no problem due to BounceBuffers which were failing the dma mapping
calls in state load logic earlier. Not sure exactly how it went away. I am
guessing that adding the PCI and MSIX state to migration solved the issue.
I am sure it was connected somehow, anyway, I am glad we can continue
with the project.
What is still needed:
* A workaround to get libvirt to support same-host migration. Since
the problems faced in v1 (mentioned above) are out of the way, we
can move further, and in doing so, we will need this.
[Adding Daniel and Michal]
Is there anyway to test live-migration for libvirt domains on the same host?
Even a 'hack' would be enough.
Sukrit, another way you could do it is by enabling nested virtualization
and have 2 Vms as hosts. I suppose the migration will take some time
Sukrit Bhatnagar (2):
hw/pvrdma: make DSR mapping idempotent in load_dsr()
hw/pvrdma: add live migration support
hw/rdma/vmw/pvrdma_main.c | 104 +++++++++++++++++++++++++++++++++++---
1 file changed, 96 insertions(+), 8 deletions(-)