Hypervisor direct memory access

A method for providing direct memory access for a device in use by a virtual machine, comprising:

• identifying, as a result of a transaction between the device and the virtual machine, a memory access request for one or more pages of a first memory by the device;
• communicating with a memory paging processor to determine whether the requested one or more pages are unmapped in the first memory;
• based on determining that the requested one or more pages are unmapped in the first memory:
• buffering at least a part of the memory access request in a second memory as a buffered memory access request;
• and
• generating a request to the memory paging processor to page-in the one or more pages;
• receiving, from the memory paging processor, an indication that the one or more pages are available in the first memory;
• in response to the indication that the one or more pages are available in the first memory, continuing the transaction based on the buffered memory access request without requiring a retry memory access request from the device.

A method for providing direct memory access, comprising:

• identifying a memory access request for one or more pages of a first memory by a peripheral device;
• communicating with a memory paging processor to determine whether the requested one or more pages are unmapped in the first memory;
• based on determining that the requested one or more pages are unmapped in the first memory:
• storing at least a part of the memory access request in a second memory as a buffered memory access request;
• and
• generating a request to the memory paging processor to page-in the one or more pages;
• receiving, from the memory paging processor, an indication that the one or more pages are available in the first memory;
• and
• in response to the indication that the one or more pages are available in the first memory, using the buffered memory access request, without requiring a retry memory access request from the peripheral device, to resume the memory access request for the one or more pages of the first memory.