On Tue, Sep 15, 2015 at 5:19 AM, Razvan Cojocaru <rcojoc...@bitdefender.com>
wrote:

> A previous version of this patch dealing with support for skipping
> the current instruction when a vm_event response requested it
> computed the instruction length in the hypervisor, adding non-trivial
> code dependencies. This patch allows a userspace vm_event client to
> simply request that the guest's EIP is set to an arbitary value,
> computed by the introspection application.
>

So in my opinion this patch introduces a feature that is not strictly tied
to emulation related vm_event paths. I could use this feature to update the
instruction pointer any time we respond to a vm_event and furthermore, it
may be benefitial to expand the scope of which registers can be updated
this way. For example, I have tools that update not just the instruction
pointer but also the stack pointer and registers used to pass function
inputs. Since we already send a snapshot of select registers to the user
with each event, we could introduce a response flag that indicates that all
registers included in that snapshot should be set to the values sent back
by the user. The user then could choose which registers need to be updated
in bulk.

What do you think?

Thanks,
Tamas
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel

Reply via email to