Re: [PATCH 0/3] arm64:msr: Add MSR driver

[Randy Dunlap]

On 11/30/20 10:05 AM, Marc Zyngier wrote:
> On 2020-11-30 17:48, Rongwei Wang wrote:
> 
>> The interfaces of this module is same as MSR module in user space, and to solve
>> the problem that ARM platform has no similar MSR module. Using this interface,
>> we did some pressure tests to test the stability and security of MSR driver. The
>> test results show that the driver will not cause system panic if various
>> illegal values and multithreading concurrent access are passed through the
>> interface.
> 
> It would certainly help if you described what problem you are trying
> to solve here. In general, giving userspace access to random system
> registers is a pretty bad idea.
> 
> Are you trying to validate a CPU? a hypervisor? Or is it just a fun way
> to check how many things you can poke before something catches fire?

I agree with the requests for justification.

Rongwei mentions that this driver functions the same as the
x86 platform MSR driver.  This one uses /dev.
I thought that the x86 driver used /sys, but I could be wrong.

Do we (or not) want cross-platform compatabilities?

Regarding permissions, /dev or /sys files have permission settings.
They don't have to be world-readable.


-- 
~Randy