Re: [Xen-devel] [PATCH v8 02/17] x86: Support indirect thunks from assembly code

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 15/01/18 10:28, Jan Beulich wrote:
>>      ctxt->io_emul_stub[10] = 0xff;
>>      ctxt->io_emul_stub[11] = 0xd1;
>>  
>> +    /*
>> +     * 3 bytes of P6_NOPS.
>> +     * TODO: untangle ideal_nops from init/livepatch Kconfig options.
>> +     */
>> +    memcpy(&ctxt->io_emul_stub[12], "\x0f\x1f\x00", 3);
> Perhaps better "P6_NOP3" in the comment? And perhaps
> __stringify(P6_NOP3) in the memcpy() invocation, which may then
> make unnecessary that part of the comment?

__stringify(P6_NOP3) really doesn't do what you expect here.  This is
the preprocessed result:

__builtin_memcpy(&ctxt->io_emul_stub[12], "0x0f,0x1f,0x00", 3);

I've fixed up the other points, but left this one opencoded.

~Andrew

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