Re: [PATCH v2] x86/xen: avoid warning in Xen pv guest with CONFIG_AMD_MEM_ENCRYPT enabled

Jan Beulich
2021-01-27T11:10:44Z

On 27.01.2021 11:26, Jürgen Groß wrote:
> On 27.01.21 10:43, Andrew Cooper wrote:
>> On 27/01/2021 09:38, Juergen Gross wrote:
>>> diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
>>> index 4409306364dc..ca5ac10fcbf7 100644
>>> --- a/arch/x86/xen/enlighten_pv.c
>>> +++ b/arch/x86/xen/enlighten_pv.c
>>> @@ -583,6 +583,12 @@ DEFINE_IDTENTRY_RAW(xenpv_exc_debug)
>>> exc_debug(regs);
>>> }
>>>
>>> +DEFINE_IDTENTRY_RAW(exc_xen_unknown_trap)
>>> +{
>>> + /* This should never happen and there is no way to handle it. */
>>> + panic("Unknown trap in Xen PV mode.");
>>
>> Looks much better.  How about including regs->entry_vector here, just to
>> short circuit the inevitable swearing which will accompany encountering
>> this panic() ?
>
> You are aware the regs parameter is struct pt_regs *, not the Xen
> struct cpu_user_regs *?
>
> So I have no idea how I should get this information without creating
> a per-vector handler.

Maybe log _RET_IP_ then (ideally decoded to a symbol), to give at
least some hint as to where this was coming from?

Jan