Re: [Xen-devel] [PATCH V2] x86/vm_event: block interrupt injection for sync vm_events

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 13.12.18 at 14:18, <rcojocaru@xxxxxxxxxxxxxxx> wrote:
> So, long story short, on VMX we first send out the vm_event, while
> processing it an interrupt / exception may become pending, before
> resuming the VCPU that has sent out the vm_event there's a Xen function
> that picks up the pending interrupt and schedules it (writes it in the
> VMCS), and only then we attempt the emulation, which may overwrite it
> (because there's only one place we can write to schedule interrupts /
> exceptions).

So perhaps the solution is indeed to change the order of how things
get done, instead of blocking interrupts? You seem to think this way
too, as per ...

> 2. Interrupts are not blocked indefinitely - only until the emulation is
> done. It could be argued that that's really the proper place for them to
> be processed anyway - on an instruction boundary, _after_ the
> in-progress instruction has finished executing. It's just that with the
> vm_event introspection thing you could say that executing the current
> instruction may take a bit longer.

... this.

Jan



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel