RE: [PATCH] [v2] x86, suspend: Save/restore extra MSR registers for suspend

[Chen, Yu C]

Hi, Nigel

> -----Original Message-----
> From: Nigel Cunningham [mailto:nigel@xxxxxxxxxxxxxxxxxxxxxx]
> Sent: Friday, August 21, 2015 8:35 PM
> To: Chen, Yu C; rjw@xxxxxxxxxxxxx; pavel@xxxxxx; tglx@xxxxxxxxxxxxx;
> mingo@xxxxxxxxxx; hpa@xxxxxxxxx
> Cc: Zhang, Rui; lenb@xxxxxxxxxx; x86@xxxxxxxxxx; linux-pm@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] [v2] x86, suspend: Save/restore extra MSR registers for
> suspend
> 
> Hi Chen.
> 
> Is there any issue with saving and restoring MSRs unconditionally? That
> would simplify the patch and make things 'just work'.
Saving/restoring unconditionally might take BIOS legal action into account,
for example, BIOS itself is willing to modify the MSR.  And Pavel suggests
using quirk to workaround in V1 patch:
https://patchwork.kernel.org/patch/7023891/

So I'm considering a common framework to save/restore these MSRs,
because user might need to protect more than one MSR during 
suspend, so..

I can modify this patch to a simpler version, for example,
Introducing two variables in struct saved_context , like
MSR_IA32_MISC_ENABLE does.

Thanks for your review

Best Regards,
Yu
> 
> Regards,
> 
> Nigel
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