Re: [RFC PATCH v4 07/11] coco: guest: arm64: Add guest APIs to read host-cached DA objects

[Aneesh Kumar K . V]

Kameron Carr <kameroncarr@xxxxxxxxxxxxxxxxxxx> writes:

>> diff --git a/drivers/virt/coco/arm-cca-guest/rsi-da.h b/drivers/virt/coco/arm-cca-guest/rsi-da.h
>> index 297cb800edc0..88067d2230ab 100644
>> --- a/drivers/virt/coco/arm-cca-guest/rsi-da.h
>> +++ b/drivers/virt/coco/arm-cca-guest/rsi-da.h
>> @@ -10,6 +10,8 @@
>>  #include <linux/pci-tsm.h>
>>  #include <asm/rsi_smc.h>
>>  
>> +#define MAX_CACHE_OBJ_SIZE	SZ_16M
>
> Why is the limit 16 MiB? I don't see that limitation in the RHI spec.
> Does the limit come from PCI TSM?
>

I based that on the SPDM MeasurementRecordLength, which is 16 MB.

-aneesh