Re: [PATCH 3/3] x86/monitor: Add new monitor event to catch all vmexits

[Tamas K Lengyel <tamas@xxxxxxxxxxxxx>]

On Thu, May 12, 2022 at 9:47 AM Tamas K Lengyel <tamas@xxxxxxxxxxxxx> wrote:
>
> On Wed, May 4, 2022 at 9:12 AM Tamas K Lengyel <tamas@xxxxxxxxxxxxx> wrote:
> >
> > On Wed, Apr 27, 2022 at 11:51 AM Tamas K Lengyel
> > <tamas.lengyel@xxxxxxxxx> wrote:
> > >
> > > Add monitor event that hooks the vmexit handler allowing for both sync and
> > > async monitoring of events. With async monitoring an event is placed on 
> > > the
> > > monitor ring for each exit and the rest of the vmexit handler resumes 
> > > normally.
> > > If there are additional monitor events configured those will also place 
> > > their
> > > respective events on the monitor ring.
> > >
> > > With the sync version an event is placed on the monitor ring but the 
> > > handler
> > > does not get resumed, thus the sync version is only useful when the VM is 
> > > not
> > > expected to resume normally after the vmexit. Our use-case is primarily 
> > > with
> > > the sync version with VM forks where the fork gets reset after sync vmexit
> > > event, thus the rest of the vmexit handler can be safely skipped. This is
> > > very useful when we want to avoid Xen crashing the VM under any 
> > > circumstance,
> > > for example during fuzzing. Collecting all vmexit information regardless 
> > > of
> > > the root cause makes it easier to reason about the state of the VM on the
> > > monitor side, hence we opt to receive all events, even for external 
> > > interrupt
> > > and NMI exits and let the monitor agent decide how to proceed.
> > >
> > > Signed-off-by: Tamas K Lengyel <tamas.lengyel@xxxxxxxxx>
> > > ---
> > > v5: wrap vmexit fields in arch.vmx structures in the public vm_event ABI
> >
> > Patch ping. Could a toolstack maintainer please take a look at this?
> > The hypervisor side already has a Reviewed-by.
>
> Patch ping.

Patch ping.

Tamas