On 03/12/2019 18:16, Tamas K Lengyel wrote:
> On Tue, Dec 3, 2019 at 1:09 PM Andrew Cooper <andrew.coop...@citrix.com>
> wrote:
>> On 03/12/2019 18:05, Tamas K Lengyel wrote:
>>>> diff --git a/xen/include/public/vm_event.h b/xen/include/public/vm_event.h
>>>> index 959083d8c4..76676ff4c0 100644
>>>> --- a/xen/include/public/vm_event.h
>>>> +++ b/xen/include/public/vm_event.h
>>>> @@ -281,6 +281,7 @@ struct vm_event_debug {
>>>> uint32_t insn_length;
>>>> uint8_t type; /* HVMOP_TRAP_* */
>>>> uint8_t _pad[3];
>>>> + uint64_t pending_dbg;
>>> This is just a nitpick but I would prefer if we had the _pad field as
>>> the last element in the struct and keep all 64-bit members up in the
>>> front.
>> Well the reason I did it like this is that this version will continue to
>> function with older introspection code. The extra field is within a
>> union and no other data moves.
>>
>> By repositioning to the start, it will almost certainly break older
>> introspection code even though it compiled correctly.
>>
>> Your choice.
> We are already bumping the interface version for the next release so
> old introspection code by design will stop working. We make no ABI
> stability guarantees between interface versions so this is a
> non-issue.
Ok fine. Updated locally, but I won't send a new version of the patch
just for this delta.
diff --git a/xen/include/public/vm_event.h b/xen/include/public/vm_event.h
index 76676ff4c0..8c24a58964 100644
--- a/xen/include/public/vm_event.h
+++ b/xen/include/public/vm_event.h
@@ -278,10 +278,10 @@ struct vm_event_singlestep {
struct vm_event_debug {
uint64_t gfn;
+ uint64_t pending_dbg;
uint32_t insn_length;
uint8_t type; /* HVMOP_TRAP_* */
uint8_t _pad[3];
- uint64_t pending_dbg;
};
struct vm_event_mov_to_msr {
However, this does raise the question of why insn_length is uint32_t.
It has a value which is at most 15.
~Andrew
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