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

[Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>]

On 12/10/18 6:59 PM, Razvan Cojocaru wrote:
> On 12/10/18 6:49 PM, Roger Pau Monné wrote:
>> On Mon, Dec 10, 2018 at 06:01:49PM +0200, Razvan Cojocaru wrote:
>>> diff --git a/xen/include/asm-arm/vm_event.h b/xen/include/asm-arm/vm_event.h
>>> index 66f2474..b63249e 100644
>>> --- a/xen/include/asm-arm/vm_event.h
>>> +++ b/xen/include/asm-arm/vm_event.h
>>> @@ -52,4 +52,10 @@ void vm_event_emulate_check(struct vcpu *v, 
>>> vm_event_response_t *rsp)
>>>      /* Not supported on ARM. */
>>>  }
>>>  
>>> +static inline
>>> +void vm_event_block_interrupts(struct vcpu *v, bool value)
>>> +{
>>> +    /* Not supported on ARM. */
>>
>> ASSERT_UNREACHABLE?
> 
> Will do (although if you look at the rest of the function in that header
> it'll break what appears to be the prior convention).

Sorry, on second thought we can't do that, because that function is
being called from the common code - which is why the function became
necessary. Specifically, this it unconditionally called in
monitor_traps(), which is used for all events (ARM and otherwise).

So it's valid to call monitor_traps() for ARM vm_events and expect it to
run without issue, which ASSERT_UNREACHABLE() would of course break.


Thanks,
Razvan

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