LIVE MIGRATION OF PARAVIRTUAL REMOTE DIRECT MEMORY ACCESS (PVRDMA) VIRTUAL MACHINES VIA HARDWARE-ASSISTED QUEUE PAIR SUSPEND/RESUME AND QUERY/RECREATE OPERATIONS

1 . A method comprising, during a switchover phase of live migrating a paravirtual remote direct memory access (PVRDM) virtual machine (VM) from a source host system to a destination host system:

invoking, by a source hypervisor of the source host system, a first application programming interface (API) exposed by a source host channel adapter (HCA) of the source host system for suspending operation of a physical queue pair residing on the source HCA and created by the PVRDMA VM;

invoking, by the source hypervisor, a second API exposed by the source HCA for querying a queue pair state of the physical queue pair, the queue pair state including an internal runtime state pertaining to one or more in-flight work request elements (WQEs) associated with the physical queue pair, the invoking of the second API resulting in the receipt of a queried queue pair state; and

transmitting, by the source hypervisor, a snapshot for a PVRDMA device used by the PVRDMA VM to a destination hypervisor of the destination host system, the snapshot including the queried queue pair state.

2 . The method of claim 1 wherein the snapshot further includes a virtual device state of the PVRDMA device, the virtual device state comprising shadow copies of remote direct memory access (RDMA) resources created by the PVRDMA VM.

3 . The method of claim 1 wherein the virtual device state includes a shadow copy of the physical queue pair, and wherein the shadow copy does not include the internal runtime state.

4 . The method of claim 1 further comprising, by the destination hypervisor:

invoking a third API exposed by a destination HCA of the destination host system for recreating, based on the queried queue pair state, the physical queue pair in a suspended state on the destination HCA, such that the recreated physical queue pair has the internal runtime state included in the queried queue pair state.

5 . The method of claim 4 further comprising, by the destination hypervisor:

invoking a fourth API exposed by the destination HCA for resuming operation of the recreated physical queue pair on the destination HCA.

6 . The method of claim 1 further comprising, upon determining that the PVRDMA VM was not successfully migrated to the destination host system:

invoking, by the source hypervisor, a third API exposed by the source HCA for resuming operation of the physical queue pair on the source HCA.

7 . The method of claim 1 wherein the PVRDMA VM carries out, using the PVRDMA device, RDMA communication with at least one bare-metal RDMA endpoint.

8 . A non-transitory computer readable storage medium having stored thereon program code executable by a source hypervisor of a source host system, the program code embodying a method comprising, during a switchover phase of live migrating a paravirtual remote direct memory access (PVRDM) virtual machine (VM) from the source host system to a destination host system:

invoking a first application programming interface (API) exposed by a source host channel adapter (HCA) of the source host system for suspending operation of a physical queue pair residing on the source HCA and created by the PVRDMA VM;

invoking a second API exposed by the source HCA for querying a queue pair state of the physical queue pair, the queue pair state including an internal runtime state pertaining to one or more in-flight work request elements (WQEs) associated with the physical queue pair, the invoking of the second API resulting in the receipt of a queried queue pair state; and

transmitting a snapshot for a PVRDMA device used by the PVRDMA VM to a destination hypervisor of the destination host system, the snapshot including the queried queue pair state.

9 . The non-transitory computer readable storage medium of claim 8 wherein the snapshot further includes a virtual device state of the PVRDMA device, the virtual device state comprising shadow copies of remote direct memory access (RDMA) resources created by the PVRDMA VM.

10 . The non-transitory computer readable storage medium of claim 8 wherein the virtual device state includes a shadow copy of the physical queue pair, and wherein the shadow copy does not include the internal runtime state.

11 . The non-transitory computer readable storage medium of claim 8 wherein upon receiving the snapshot, the destination hypervisor:

invokes a third API exposed by a destination HCA of the destination host system for recreating, based on the queried queue pair state, the physical queue pair in a suspended state on the destination HCA, such that the recreated physical queue pair has the internal runtime state included in the queried queue pair state.

12 . The non-transitory computer readable storage medium of claim 11 wherein the destination hypervisor further:

invokes a fourth API exposed by the destination HCA for resuming operation of the recreated physical queue pair on the destination HCA.

13 . The non-transitory computer readable storage medium of claim 8 wherein the method further comprises, upon determining that the PVRDMA VM was not successfully migrated to the destination host system:

invoking, by the source hypervisor, a third API exposed by the source HCA for resuming operation of the physical queue pair on the source HCA.

14 . The non-transitory computer readable storage medium of claim 8 wherein the PVRDMA VM carries out, using the PVRDMA device, RDMA communication with at least one bare-metal RDMA endpoint.

15 . A host system comprising:

a hypervisor including a paravirtual remote direct memory access (PVRDMA) device;

a host channel adapter (HCA);

a PVRDMA virtual machine (VM) using the PVRDMA device for remote direct memory access (RDMA) communication; and

a non-transitory computer readable medium having stored thereon program code that causes the hypervisor to, during a switchover phase of live migrating the PVRDMA VM to a destination host system:

invoke a first application programming interface (API) exposed by the HCA for suspending operation of a physical queue pair residing on the HCA and created by the PVRDMA VM;

invoke a second API exposed by the source HCA for querying a queue pair state of the physical queue pair, the queue pair state including an internal runtime state pertaining to one or more in-flight work request elements (WQEs) associated with the physical queue pair, the invoking of the second API resulting in the receipt of a queried queue pair state; and

transmit a snapshot for the PVRDMA device to a destination hypervisor of the destination host system, the snapshot including the queried queue pair state.

16 . The host system of claim 15 wherein the snapshot further includes a virtual device state of the PVRDMA device, the virtual device state comprising shadow copies of RDMA resources created by the PVRDMA VM.

17 . The host system of claim 15 wherein the virtual device state includes a shadow copy of the physical queue pair, and wherein the shadow copy does not include the internal runtime state.

18 . The host system of claim 15 wherein upon receiving the snapshot, the destination hypervisor:

invokes a third API exposed by a destination HCA of the destination host system for recreating, based on the queried queue pair state, the physical queue pair in a suspended state on the destination HCA, such that the recreated physical queue pair has the internal runtime state included in the queried queue pair state.

19 . The host system of claim 18 wherein the destination hypervisor further:

invokes a fourth API exposed by the destination HCA for resuming operation of the recreated physical queue pair on the destination HCA.

20 . The host system of claim 15 wherein the program code further causes the hypervisor to, upon determining that the PVRDMA VM was not successfully migrated to the destination host system:

invoke a third API exposed by the source HCA for resuming operation of the physical queue pair on the source HCA.

21 . The host system of claim 15 wherein the PVRDMA VM carries out, using the PVRDMA device, RDMA communication with at least one bare-metal RDMA endpoint.