Re: [Xen-devel] [PATCH v3 5/6] x86/XPTI: reduce .text.entry

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 15.03.18 at 18:10, <andrew.cooper3@xxxxxxxxxx> wrote:
> On 13/03/18 13:50, Jan Beulich wrote:
>> --- a/xen/arch/x86/x86_64/entry.S
>> +++ b/xen/arch/x86/x86_64/entry.S
>> @@ -14,8 +14,6 @@
>>  #include <public/xen.h>
>>  #include <irq_vectors.h>
>>  
>> -        .section .text.entry, "ax", @progbits
>> -
>>  /* %rbx: struct vcpu */
>>  ENTRY(switch_to_kernel)
>>          leaq  VCPU_trap_bounce(%rbx),%rdx
>> @@ -34,8 +32,107 @@ ENTRY(switch_to_kernel)
>>          movb  %cl,TRAPBOUNCE_flags(%rdx)
>>          call  create_bounce_frame
>>          andl  $~X86_EFLAGS_DF,UREGS_eflags(%rsp)
> 
> Newline here please, as test_all_events is logically a separate thing. 

I actually disagree in cases where the label sits in the middle of
straight line code.

> It might be worth using an ALIGN, given how many jmps land here.

That'll again get us into the discussion of suitable NOPs. We'd
have to extend ALIGN by ALTERNATIVE_NOP for the result to
be as desired for all cases. Generally I'd expect straight line
execution here to be (one of) the most common ways to reach
that label.

Furthermore I intentionally didn't want to alter any of the moved
code, other than its spelling/formatting.

> Otherwise, Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

I'll wait with recording this until the above was clarified.

Jan


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