Simultaneous kernel mode and user mode access to a device using the NVMe interface

A non-transitory, computer-readable medium having stored thereon computer executable instructions that, when executed by a host computer system having a host memory space divided into at least a kernel space with a block I/O layer and a plurality of user spaces, enable simultaneous kernel mode access and user mode access to a non-volatile memory express (NVMe) device using the NVMe interface by causing the host computer system to perform at least the following:

• provide kernel mode access to an NVMe device by:
• creating a first set of one or more queues by at least reserving a first range of memory addresses in the kernel space;
• providing a location address and size of the first set of queues to a controller of the NVMe device;
• and
• simultaneously provide user mode access to the controller of the NVMe device in response to receiving a request for user mode access from a user application process running on the host computer system by:
• creating a second set of one or more queues by at least reserving a second range of memory addresses mapped for use by the user application process, and
• providing a location address and size of the second set of queues to the user application process and the controller of the NVMe device;
• such that the NVMe device is able to communicate with an application process via the first set of queues or the second set of queues, the second set of queues bypassing the block I/O layer of the kernel space.

A host computer system that supports simultaneous kernel mode access and user mode access to a non-volatile memory express (NVMe) device using the NVMe interface, the system comprising:

• an operating system configured to:
• run a user application and a kernel mode process,
• create a host memory space divided into at least a kernel space having a block I/O layer and a plurality of user spaces;
• and
• a memory device driver configured to:
• provide kernel mode access to an NVMe device by:
• creating a first set of one or more queues by at least reserving a first range of memory addresses in the kernel space,
• providing a location address and size of the first set of queues to a controller of the NVMe device, and
• simultaneously provide user mode access to the controller of the NVMe device in response to receiving a request for user mode access from the user application process running on the host computer system, by:
• creating a second set of one or more queues by at least reserving a second range of memory addresses mapped for use by the user application, and
• providing a location address and size of the second set of queues to the user application and the controller of the NVMe device:,
• such that the NVMe device is able to communicate with an application process via the first set of queues or the second set of queues, the second set of queues bypassing the block I/O layer of the kernel space.