Re: [PATCH v5 20/22] target/arm: Create tagged ram when MTE is enabled

[Richard Henderson]

On 12/5/19 10:40 AM, Peter Maydell wrote:
>> +         * If it is, we must allocate the ram to back that up.
>> +         */
>> +        if (object_property_find(cpuobj, "tag-memory", NULL)) {
>> +            if (!tag_sysmem) {
>> +                tag_sysmem = g_new(MemoryRegion, 1);
>> +                memory_region_init(tag_sysmem, OBJECT(machine),
>> +                                   "tag-memory", UINT64_MAX / 32);
>> +
>> +                if (vms->secure) {
>> +                    secure_tag_sysmem = g_new(MemoryRegion, 1);
>> +                    memory_region_init(secure_tag_sysmem, OBJECT(machine),
>> +                                       "secure-tag-memory", UINT64_MAX / 
>> 32);
>> +
>> +                    /* As with ram, secure-tag takes precedence over tag.  
>> */
>> +                    memory_region_add_subregion_overlap(secure_tag_sysmem, 
>> 0,
>> +                                                        tag_sysmem, -1);
>> +                }
>> +            }
> 
> Are there really separate S and NS tag RAMs?

Implementation defined, I believe.  As with everything about tag storage, it
would seem.  But since there are separate S and NS normal RAMS, I create
separate tag spaces to match.


r~