From mboxrd@z Thu Jan  1 00:00:00 1970
From: Razvan Cojocaru <rcojocaru@bitdefender.com>
Subject: Re: [PATCH V9 for-4.5 4/4] xen: Handle resumed
 instruction based on previous mem_event reply
Date: Wed, 17 Sep 2014 13:54:43 +0300
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To: Jan Beulich <JBeulich@suse.com>
Cc: kevin.tian@intel.com, keir@xen.org, ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com, andrew.cooper3@citrix.com, eddie.dong@intel.com, tim@xen.org, jun.nakajima@intel.com, xen-devel@lists.xenproject.org, ian.jackson@eu.citrix.com
List-Id: xen-devel@lists.xenproject.org

On 09/17/14 13:48, Jan Beulich wrote:
>>>> On 17.09.14 at 10:29, <rcojocaru@bitdefender.com> wrote:
>> --- a/xen/include/public/mem_event.h
>> +++ b/xen/include/public/mem_event.h
>> @@ -31,11 +31,19 @@
>>  #include "io/ring.h"
>>  
>>  /* Memory event flags */
>> -#define MEM_EVENT_FLAG_VCPU_PAUSED  (1 << 0)
>> -#define MEM_EVENT_FLAG_DROP_PAGE    (1 << 1)
>> -#define MEM_EVENT_FLAG_EVICT_FAIL   (1 << 2)
>> -#define MEM_EVENT_FLAG_FOREIGN      (1 << 3)
>> -#define MEM_EVENT_FLAG_DUMMY        (1 << 4)
>> +#define MEM_EVENT_FLAG_VCPU_PAUSED     (1 << 0)
>> +#define MEM_EVENT_FLAG_DROP_PAGE       (1 << 1)
>> +#define MEM_EVENT_FLAG_EVICT_FAIL      (1 << 2)
>> +#define MEM_EVENT_FLAG_FOREIGN         (1 << 3)
>> +#define MEM_EVENT_FLAG_DUMMY           (1 << 4)
>> +/*
>> + * Emulate the fault-causing instruction (if set in the event response flags).
>> + * This will allow the guest to continue execution without lifting the page
>> + * access restrictions.
>> + */
>> +#define MEM_EVENT_FLAG_EMULATE         (1 << 5)
>> +/* Same as MEM_EVENT_FLAG_EMULATE, but with write operations disabled. */
> 
> As we've gone through this incrementally suppressing more and more
> operations, I think you should be very explicit here and say "...
> with write operations or operations potentially having side effects
> (like memory mapped or port I/O) disabled".

Of course, thanks for the comment! Will do.


Thanks,
Razvan Cojocaru