Re: [Minios-devel] [UNIKRAFT PATCH v2 2/9] plat/kvm: Make mxcsr_ptr in entry64.S a 32-bit value

[Yuri Volchkov <yuri.volchkov@xxxxxxxxx>]

Hi,

I pushed this and the previous patches. No need to send them in the v3.

Thanks, Yuri.

Yuri Volchkov <yuri.volchkov@xxxxxxxxx> writes:

> Reviewed-by: Yuri Volchkov <yuri.volchkov@xxxxxxxxx>
>
> Florian Schmidt <florian.schmidt@xxxxxxxxx> writes:
>
>> LDMXCSR reads 32 bits into the register. If mxcsr_ptr is only a .word
>> (and thus 16 bits), the instruction reads adjacent bytes into the MXCSR
>> register, which can to produce #GP faults on LDMXCSR when those adjacent
>> bytes contain 1's in bit locations that are reserved in MXCSR.
>>
>> Signed-off-by: Florian Schmidt <florian.schmidt@xxxxxxxxx>
>> ---
>>  plat/kvm/x86/entry64.S | 3 +--
>>  1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/plat/kvm/x86/entry64.S b/plat/kvm/x86/entry64.S
>> index 35738b67..dc3614a2 100644
>> --- a/plat/kvm/x86/entry64.S
>> +++ b/plat/kvm/x86/entry64.S
>> @@ -160,8 +160,7 @@ gdt64_ptr:
>>  
>>  .type mxcsr_ptr, @object
>>  mxcsr_ptr:
>> -    .word 0x1f80                    /* Intel SDM power-on default */
>> -
>> +    .long 0x1f80                    /* Intel SDM power-on default */
>>  
>>  
>>  #include "pagetable.S"
>> -- 
>> 2.19.2
>>
>
> -- 
> Yuri Volchkov
> Software Specialist
>
> NEC Europe Ltd
> Kurfürsten-Anlage 36
> D-69115 Heidelberg

-- 
Yuri Volchkov
Software Specialist

NEC Europe Ltd
Kurfürsten-Anlage 36
D-69115 Heidelberg

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