Re: [RFC] new MSR r/w functions per CPU

From: H. Peter Anvin
Date: Wed Dec 13 2006 - 17:23:04 EST


Dave Jones wrote:

Exposing the guts of the msr driver like that doesn't seem too clean.
For in-kernel use, why not just add something like this..
(note:not even compile tested)..


Well, that *is* the guts of the MSR driver.

void rdmsr_on_cpu(unsigned int cpu, unsigned long msr, unsigned long *lo, unsigned long *hi)
{
cpumask_t oldmask;

oldmask = current->cpus_allowed;
set_cpus_allowed(current, cpumask_of_cpu(cpu));

rdmsr(msr, &lo, &hi);

set_cpus_allowed(current, oldmask);
}


[The above doesn't work, by the way. This approach was discussed a long time ago, and vetoed due to the potential for deadlock.]

-hpa
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/