Re: [tip:x86/asm] x86/asm/msr: Make wrmsrl_safe() a function

From: Ingo Molnar
Date: Fri Jun 05 2015 - 06:04:55 EST



* H. Peter Anvin <hpa@xxxxxxxxx> wrote:

> Shouldn't we make it a proper function sine there is going to have to be a
> function call involved anyway?

Yeah, so what I think should be done instead is to flip around the API:
make wrmsrl_safe() the primary API and derive wrmsr_safe() from that,
because it's the saner API and because we have 3 times more wrmsrl_safe()
users right now!

And I'd make _that_ mapping inline, which would catch crap like:

./arch/x86/include/asm/msr.h: return wrmsr_safe(msr, (u32)val, (u32)(val >> 32));
./arch/x86/xen/enlighten.c: wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));

and would turn it back into wrmsrl_safe(pfn)/etc. seemlessly.

In addition to that we might even phase out the high/low API altogether, as code
like this:

!wrmsr_safe(MSR_EFER,
header->pmode_efer_low,
header->pmode_efer_high))

should probably use a single u64.

But crappy paravirt indirections get in the way of an easy, trivial restructuring,
as usual...

Thanks,

Ingo
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