Allowing world switches between virtual machines via hypervisor world switch security setting

A method performed by a server comprising a hypervisor configured to manage execution of virtual machines, wherein the hypervisor is configured to initiate context switches between virtual machines executable by one or more processor cores of the server, wherein the context switches between virtual machines allow at least a portion of a processor state associated with a first virtual machine to remain during execution of a subsequent virtual machine, wherein the hypervisor is configured to initiate world switches between virtual machines executable by the one or more processor cores, wherein world switches between virtual machines eliminate at least a processor core cache, register, or pipeline state associated with the first virtual machine when switching to execution of the subsequent virtual machine, and wherein the hypervisor is configured to implement continuous world switch security for one or more of the virtual machines, the method comprising:

• detecting, by the server, a world switch indicator associated with a task for a cloud customer;
• activating, by the server, a hypervisor world switch security setting in response to detecting that the world switch indicator requires world switches, and not context switches, between a virtual machine including the task for the cloud customer and other virtual machines executable by the server;
• and
• when the hypervisor world switch security setting is on, allowing, by the hypervisor, world switches, and not context switches, between a virtual machine including the task for the cloud customer and other virtual machines executable by the server, wherein allowing world switches and not context switches comprises:
• detecting, by the hypervisor, during execution of the virtual machine including the task, the hypervisor world switch security setting for the virtual machine including the task, to determine whether the hypervisor world switch security setting is on for the virtual machine including the task.

A non-transitory computer readable medium including computer executable instructions implementing a hypervisor configured to apply continuous world switch security for one or more virtual machines, comprising:

• instructions implementing a hypervisor, wherein:
• the hypervisor is configured to initiate context switches between virtual machines executable by one or more processor cores included in a server, wherein context switches between virtual machines allow at least a portion of a processor state associated with a first virtual machine to remain during execution of a subsequent virtual machine;
• the hypervisor is configured to initiate world switches between virtual machines executable by the one or more processor cores included in the server, wherein world switches between virtual machines eliminate at least a processor core cache, register, or pipeline state associated with the first virtual machine when switching to execution of the subsequent virtual machine;
• the hypervisor is configured to implement a hypervisor world switch security setting associated with a task for a cloud customer, so that:
• when the hypervisor world switch security setting is on, the hypervisor is configured to allow world switches, and not context switches, between a virtual machine including the task for the cloud customer and other virtual machines executable by the server;
• and
• when the hypervisor world switch security setting is off, the hypervisor is configured to allow world switches and context switches between the virtual machine including the task for the cloud customer and other virtual machines executable by the server;
• wherein the hypervisor is configured to detect the hypervisor world switch security setting at least in part by reference, during execution of the virtual machine including the task, to the hypervisor world switch security setting for the virtual machine including the task to determine whether the hypervisor world switch security setting is on for the virtual machine including the task.