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

[Rongwei Wang]

> 2020年12月1日 下午11:25，Borislav Petkov <bp@xxxxxxxxx> 写道：
> 
> On Tue, Dec 01, 2020 at 11:17:39PM +0800, Rongwei Wang wrote:
>> In ARM, the system registers can only be accessed through msr and mrs,
>> so the problem created by MSR driver (depend on rdmsr and wrmsr) in
>> x86 is not necessarily present in ARM, which is very different from
>> x86.
> 
> No, the point I'm making is that it doesn't matter what the architecture
> does or does not, register *writes* from userspace are a bad bad idea
> for the reasons I described.
Sorry, I was away for two days and didn't reply in time.
In fact, we find MSR in the x86 architecture to be a particularly useful interface. It helped us a lot when we were doing some kernel debugging. So we consider implementing a similar feature in ARM.
So as a debugging tool, could it exist, e.g. if I change CONFIG_ARM64_MSR to CONFIG_ARM64_MSR_DEBUG or others. Do you think this adjustment is possible?
> 
> -- 
> Regards/Gruss,
>    Boris.
> 
> https://people.kernel.org/tglx/notes-about-netiquette

Regards,
Rongwei Wang.