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



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.

Tamas



 


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