Re: [PATCH 5/6] x86/alternative: Relocate all insn-relative fields

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 23/04/2024 3:59 pm, Jan Beulich wrote:
> On 22.04.2024 20:14, Andrew Cooper wrote:
>> @@ -317,14 +338,23 @@ static void init_or_livepatch 
>> _apply_alternatives(struct alt_instr *start,
>>                           */
>>                          goto skip_this_alternative;
>>                      }
>> +
>> +                    continue;
>>                  }
>> -                else if ( force && system_state < SYS_STATE_active )
>> -                    ASSERT_UNREACHABLE();
> This (and the other one below) is related to altcall patching, which you
> say you mean to leave alone: During the 2nd pass, no un-processed CALL /
> JMP should occur anymore that aren't altcall related.

Calling the parameter "force" was a mistake and I regret not asking for
it to change.  It should be a SEAL_ALTCALL flag of some form or another.

But, that's not what this ASSERT() is doing.  This assert is only
checking that you don't try sealing a still-NULL altcall early, which is
only doing nothing more than checking that the caller of
_apply_alternatives() passed a parameter correctly.

~Andrew