Virtualizing NVDIMM WPQ flushing with minimal overhead

A non-transitory computer readable storage medium having stored thereon program code executable by a computer system, the program code embodying a method for virtualizing NVDIMM (non-volatile dual-inline memory module) WPQ (write pending queue) flushing with minimal overhead, the method comprising:

• allocating, by a hypervisor of a computer system, a virtual flush hint address (FHA) for a virtual machine (VM), the virtual FHA being associated with one or more physical FHAs corresponding to one or more physical memory controllers of the computer system, the allocating comprising:
• selecting a guest physical address from a guest address space of the VM;
• assigning the selected guest physical address to the virtual FHA;
• adding the virtual FHA to a virtual FHA table for the VM;
• and
• exposing the virtual FHA table to the VM;
• determining, by the hypervisor, whether one or more physical NVDIMMs of the computer system support WPQ flushing;
• and
• if the one or more physical NVDIMMs support WPQ flushing, write protecting, by the hypervisor, a guest physical address (GPA) to host physical address (HPA) mapping for the virtual FHA in a page table of the computer system.

A computer system comprising:

• a processor;
• one or more physical NVDIMMs (non-volatile dual-inline memory modules);
• one or more physical memory controllers;
• and
• a non-transitory computer readable medium having stored thereon program code for virtualizing NVDIMM WPQ (write pending queue) flushing with minimal overhead, the program code causing the processor to:
• allocate a virtual flush hint address (FHA) for a virtual machine (VM), the virtual FHA being associated with one or more physical FHAs corresponding to the one or more physical memory controllers, the allocating comprising:
• selecting a guest physical address from a guest address space of the VM;
• assigning the selected guest physical address to the virtual FHA;
• adding the virtual FHA to a virtual FHA table for the VM;
• and
• exposing the virtual FHA table to the VM;
• determine whether the one or more physical NVDIMMs support WPQ flushing;
• and
• if the one or more physical NVDIMMs support WPQ flushing, write protect a guest physical address (GPA) to host physical address (HPA) mapping for the virtual FHA in a page table of the computer system.