Re: [PATCH] [RFC] Save/restore MISC_ENABLE register

[H. Peter Anvin]

On 06/07/2010 09:14 AM, Ondrej Zary wrote:
> Save/restore MISC_ENABLE register on suspend/resume.
> This fixes OOPS (invalid opcode) on resume from STR on Asus P4P800-VM, which
> wakes up with MWAIT disabled.
> 
> Is this a correct thing to do? Is it OK on x86_64?

This MSR isn't available on all processors, and thus cannot be saved and
restored unconditionally like this.  On the save path, one can use
rdmsr_safe(); on the wakeup path it's not clear to me it is safe to do
so, so it would be better to save a presence flag on the save path and
conditionalize the write.

	-hpa
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