Virtual machine state replication using DMA write records
First Claim
Patent Images
1. A method, comprising:
- performing, at a source virtualization host;
determining, by a virtualization management component of the source virtualization host, that an operation to save a representation of a state of a particular virtual machine instantiated at the source virtualization host is to be implemented for a live migration of the particular virtual machine to a target virtualization host;
directing a DMA (direct memory access)-capable device of the source virtualization host to generate respective DMA write records corresponding to one or more DMA write operations directed to the physical memory of the source virtualization host from the DMA-capable device;
generating, by the DMA-capable device, a particular DMA write record indicating a portion of physical memory modified by a particular DMA write operation, wherein the particular DMA write record comprises at least (a) a memory address to which the particular DMA write operation is directed, and (b) a write size of the particular DMA write operation;
storing, by the DMA-capable device, the particular DMA write record in a record buffer accessible from the virtualization management component, wherein the record buffer comprises one or more slots including a particular slot into which the particular DMA write record was stored by the DMA-capable device;
determining, by the virtualization management component, using the record buffer, that the portion of physical memory (a) has been modified by the DMA-capable device and (b) is allocated to the particular virtual machine;
initiating a copy of the portion of the physical memory modified by the DMA-capable device to a target location;
providing, by the virtualization management component, an indication to the DMA-capable device that the particular DMA write record has been examined and that the particular slot is available for re-use; and
re-using, by the DMA-capable device, the particular slot to store another DMA write record corresponding to a different DMA write operation.
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Abstract
A DMA-capable device of a virtualization host stores a DMA write record, indicating a portion of host memory that is targeted by a DMA write operation, in a write buffer accessible from a virtualization management component of the host. The virtualization management component uses the DMA write record to identify a portion of memory to be copied to a target location to save a representation of a state of a particular virtual machine instantiated at the host.
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Citations
17 Claims
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1. A method, comprising:
performing, at a source virtualization host; determining, by a virtualization management component of the source virtualization host, that an operation to save a representation of a state of a particular virtual machine instantiated at the source virtualization host is to be implemented for a live migration of the particular virtual machine to a target virtualization host; directing a DMA (direct memory access)-capable device of the source virtualization host to generate respective DMA write records corresponding to one or more DMA write operations directed to the physical memory of the source virtualization host from the DMA-capable device; generating, by the DMA-capable device, a particular DMA write record indicating a portion of physical memory modified by a particular DMA write operation, wherein the particular DMA write record comprises at least (a) a memory address to which the particular DMA write operation is directed, and (b) a write size of the particular DMA write operation; storing, by the DMA-capable device, the particular DMA write record in a record buffer accessible from the virtualization management component, wherein the record buffer comprises one or more slots including a particular slot into which the particular DMA write record was stored by the DMA-capable device; determining, by the virtualization management component, using the record buffer, that the portion of physical memory (a) has been modified by the DMA-capable device and (b) is allocated to the particular virtual machine; initiating a copy of the portion of the physical memory modified by the DMA-capable device to a target location; providing, by the virtualization management component, an indication to the DMA-capable device that the particular DMA write record has been examined and that the particular slot is available for re-use; and re-using, by the DMA-capable device, the particular slot to store another DMA write record corresponding to a different DMA write operation. - View Dependent Claims (2, 3, 4)
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5. A computer system, comprising:
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one or more processors; a memory; and a DMA-capable device configured to perform DMA write operations directed to the memory; wherein the memory comprises instructions that when executed on the one or more processors implement a virtualization management component configured to; in response to a determination that a representation of a state of a particular virtual machine instantiated at the computer system is to be replicated, issue a command to the DMA-capable device to store, in one or more record buffers accessible from the virtualization management component, respective DMA write records corresponding to DMA write operations directed to the memory from the DMA-capable device; examine a particular DMA write record written to a particular record buffer of the one or more record buffers by the DMA-capable device to identify a portion of memory that has been modified during a particular phase of an operation to save the representation of the state, wherein the particular record buffer comprises one or more slots including a particular slot into which the particular DMA write record was written by the DMA-capable device; initiate a replication of the portion of memory to a target location; and provide an indication to the DMA-capable device that the particular DMA write record has been examined and that the particular slot is available for storing another DMA write record corresponding to a different DMA write operation. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A non-transitory computer-accessible storage medium storing program instructions that when executed on one or more processors implement a virtualization management component configured to:
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determine that a representation of a state of a particular virtual machine instantiated at a virtualization host is to be replicated; examine a particular DMA write record written to a particular record buffer by a DMA-capable device of the virtualization host to identify a portion of memory that has been modified by a DMA write operation initiated at the DMA-capable device during a particular time window, wherein the particular record buffer comprises one or more slots including a particular slot into which the particular DMA write record was written by the DMA-capable device; initiate a replication of the portion of memory to a target location; and provide an indication to the DMA-capable device that the particular DMA write record has been examined and that the particular slot is available for storing another DMA write record corresponding to a different DMA write operation.
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Specification