[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [PATCH v2 2/5] vm_event: Implement ARM SMC events

On 05/04/2016 04:26 PM, Julien Grall wrote:
> I may misunderstand some parts of the vm event subsystem. To get/set the
> full set of registers, the user will have to use the
> DOMCTL_{set,get}vcpucontext, correct? So why does Xen expose a part of
> the vCPU context through the vm_event?

Because DOMCTL_{set,get}vcpucontext is expensive, and a serious
introspection application will receive hundreds or thousands of events
per second.

Having what's most commonly needed being sent with the vm_event
eliminates the need for extra hypercalls and can make the difference
between a responsive and an unusable userspace introspection application.


Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.