Re: [Xen-devel] [PATCH v5 06/30] ARM: GICv3 ITS: allocate device and collection table

[Andre Przywara <andre.przywara@xxxxxxx>]

Hi,

On 06/04/17 15:44, Julien Grall wrote:
> Hi Andre,
> 
> On 06/04/17 00:18, Andre Przywara wrote:
>> diff --git a/xen/include/asm-arm/gic_v3_its.h
>> b/xen/include/asm-arm/gic_v3_its.h
>> index 295eb22..6e51b98 100644
>> --- a/xen/include/asm-arm/gic_v3_its.h
>> +++ b/xen/include/asm-arm/gic_v3_its.h
>> @@ -37,6 +37,11 @@
>>  #define GITS_BASER7                     0x138
>>
>>  /* Register bits */
>> +#define GITS_VALID_BIT                  BIT_ULL(63)
>> +
>> +#define GITS_CTLR_QUIESCENT             BIT(31)
>> +#define GITS_CTLR_ENABLE                BIT(0)
>> +
>>  #define GITS_TYPER_DEVIDS_SHIFT         13
>>  #define GITS_TYPER_DEVIDS_MASK          (0x1fUL <<
>> GITS_TYPER_DEVIDS_SHIFT)
>>  #define GITS_TYPER_DEVICE_ID_BITS(r)    (((r &
>> GITS_TYPER_DEVIDS_MASK) >> \
>> @@ -52,6 +57,33 @@
>>  #define GITS_TYPER_ITT_SIZE(r)          ((((r) &
>> GITS_TYPER_ITT_SIZE_MASK) >> \
>>                                                  
>> GITS_TYPER_ITT_SIZE_SHIFT) + 1)
>>
>> +#define GITS_IIDR_VALUE                 0x34c
> 
> Just spotted this. This value belongs to vgic-its-v3.c as this is a
> "made up value" for the emulation (i.e patch #8).

Ah, good spot. While it's easy to move this, I wonder if we should have
something pseudo-unique for Xen.
In the KVM emulation we use this implementer value (which means "ARM"),
plus an ASCII "K" in the upper 8 bits. This allows the Linux ITS driver
to apply specific errata workarounds, if needed.
Shall I use a similar approach with "X" instead?
This would allow us to later push Xen-emulation specific fixes into
Linux shall we need it.

> With that moved:
> 
> Reviewed-by: Julien Grall <julien.grall@xxxxxxx>

Thanks!

Andre.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel