On 1/6/23 11:12, Peter Maydell wrote:
The trouble with this idea is that not all instances of the same
class are actually necessarily the same. For instance, if you
have a system with both (a) a Cortex-A53 with a PMU, and
(b) a Cortex-A53 without a PMU, then they're both instances of
the same class, but they shouldn't be sharing the coprocessor
register hashtable because they don't have an identical set of
system registers.
This kind of same-CPU-type-heterogenous-configuration system is
not something we're currently using on A-profile, but we do have
it for M-profile (the sse200 has a dual-core setup where only one
of the CPUs has an FPU), so it's not totally outlandish.
Yes, I know. See patch 29 where I moved the vfp and dsp properties off of the m-profile
cpus and created new cpu classes instead, specifically for the sse220.
It's not scalable, I'll grant you, but it's hard to design for something we're not using.
What we use now, apart from the sse200, are common properties set on the command-line.
If we were presented with the class properties early enough, we could create sub-classes
with the desired properties before instantiating the objects that go with.
Anyway, it seems like we ought to have some solution that does not involve repeating the
same id register finalization + cpregs hash table construction per cpu -- especially for
user-only.
r~
