Virtual processor scheduling via memory monitoring

A computer system, comprising:

• a memory to store a data structure accessible by guest software running on a first virtual processor, the data structure comprising a polling flag and a waiting task flag associated with the first virtual processor;
• and
• a processor, operatively coupled to the memory, to:
• configure a virtual machine control structure (VMCS) associated with a virtual machine to allow the virtual machine execute memory monitoring instructions without triggering a virtual machine exit event;
• detect an event associated with a first virtual processor associated with the virtual machine running on the processor;
• test a polling flag residing in a memory accessible by guest software running on the first virtual processor, wherein a first state of the polling flag indicates that the first virtual processor is monitoring modifications to a memory region comprising a waiting task flag, and wherein the waiting task flag indicates whether a task has been queued for the first virtual processor;
• set the polling flag to a second state, wherein the second state prevents a second virtual processor associated with the virtual machine from notifying the first virtual processor via the waiting task flag, and wherein testing the polling flag and setting the polling flag to the second state is performed in an atomic operation;
• and
• process the detected event.

A non-transitory computer-readable storage medium comprising executable instructions that, when executed by a physical processor of a host computer system, cause the physical processor to:

• configure a virtual machine control structure (VMCS) associated with a virtual machine to allow the virtual machine execute memory monitoring instructions without triggering a virtual machine exit event;
• detect an event associated with a first virtual processor associated with the virtual machine running on a physical processor of the host computer system;
• test a polling flag residing in a memory accessible by guest software running on the first virtual processor, wherein a first state of the polling flag indicates that the first virtual processor is monitoring modifications to a memory region comprising a waiting task flag, and wherein the waiting task flag indicates whether a task has been queued for the first virtual processor;
• set the polling flag to a second state, wherein the second state prevents a second virtual processor associated with the virtual machine from notifying the first virtual processor via the waiting task flag, and wherein testing the polling flag and setting the polling flag to the second state is performed in an atomic operation;
• and
• process the detected event.