Re: [PATCH v1 1/3] i386: Remove the limitation of IP payloads for Intel PT

[Paolo Bonzini]

On 25/09/20 18:54, Eduardo Habkost wrote:
> On Fri, Sep 25, 2020 at 04:42:26PM +0000, Strong, Beeman wrote:
>> LIP=0 will differ from LIP=1 behavior only when CSbase is non-zero, which 
>> requires 32-bit code.  In that case a LIP=0 implementation will provide only 
>> the EIP offset from CSbase in IP packets (like TIP or FUP), while LIP=1 
>> implementation will provide the full LIP (CSbase + EIP offset).
>>
> Thanks.  Is it possible to make KVM emulate LIP=0 behavior
> correctly on LIP=1 hosts, or vice versa?

No, it's not possible.  KVM doesn't have a say on what the processor
writes in the tracing packets.

Paolo