Subject: Re: [PATCH 05/26] arm64: Document SW reserved PTE/PMD bits in Stage-2 descriptors

From: Marc Zyngier <[email-masked]>
Date: Wed, 06 May 2020 10:39:59 +0100

Hi Andrew,

On 2020-05-05 16:59, Andrew Scull wrote:
> On Wed, Apr 22, 2020 at 01:00:29PM +0100, Marc Zyngier wrote:
>> Advertise bits [58:55] as reserved for SW in the S2 descriptors.
>> 
>> Signed-off-by: Marc Zyngier <[email-masked]>
>> ---
>>  arch/arm64/include/asm/pgtable-hwdef.h | 2 ++
>>  1 file changed, 2 insertions(+)
>> 
>> diff --git a/arch/arm64/include/asm/pgtable-hwdef.h 
>> b/arch/arm64/include/asm/pgtable-hwdef.h
>> index 6bf5e650da788..7eab0d23cdb52 100644
>> --- a/arch/arm64/include/asm/pgtable-hwdef.h
>> +++ b/arch/arm64/include/asm/pgtable-hwdef.h
>> @@ -177,10 +177,12 @@
>>  #define PTE_S2_RDONLY		(_AT(pteval_t, 1) << 6)   /* HAP[2:1] */
>>  #define PTE_S2_RDWR		(_AT(pteval_t, 3) << 6)   /* HAP[2:1] */
>>  #define PTE_S2_XN		(_AT(pteval_t, 2) << 53)  /* XN[1:0] */
>> +#define PTE_S2_SW_RESVD		(_AT(pteval_t, 15) << 55) /* Reserved for SW 
>> */
>> 
>>  #define PMD_S2_RDONLY		(_AT(pmdval_t, 1) << 6)   /* HAP[2:1] */
>>  #define PMD_S2_RDWR		(_AT(pmdval_t, 3) << 6)   /* HAP[2:1] */
>>  #define PMD_S2_XN		(_AT(pmdval_t, 2) << 53)  /* XN[1:0] */
>> +#define PMD_S2_SW_RESVD		(_AT(pmdval_t, 15) << 55) /* Reserved for SW 
>> */
>> 
>>  #define PUD_S2_RDONLY		(_AT(pudval_t, 1) << 6)   /* HAP[2:1] */
>>  #define PUD_S2_RDWR		(_AT(pudval_t, 3) << 6)   /* HAP[2:1] */
>> --
>> 2.26.1
>> 
>> _______________________________________________
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>> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
> 
> This is consistent with "Attribute fields in stage 1 VMSAv8-64 Block 
> and
> Page descriptors"

Do you mean "stage 2" instead? The reserved bits are the same, but I 
want
to be sure we have looked at the same thing (ARM DDI 0487F.a, D5-2603).

> Reviewed-by: Andrew Scull <[email-masked]>

Thanks,

          M.
-- 
Jazz is not dead. It just smells funny...

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