On Wed, May 30, 2012 at 04:35:41PM +0100, Jan Beulich wrote:

quoted

quoted

quoted

On 30.05.12 at 17:15, "H. Peter Anvin" [off-list ref] wrote:

On 05/30/2012 08:08 AM, Jan Beulich wrote:

quoted

Xen does trap and emulate (possibly just ignore) both instructions.

Then why the fsck is there paravirt_crap on this?

I have no clue. Jeremy, Konrad?

No idea. The git 132ec92f says:

Borislav Petkov [off-list ref]
Date:   Mon Aug 31 09:50:09 2009 +0200

    x86, msr: Add rd/wrmsr interfaces with preset registers

    native_{rdmsr,wrmsr}_safe_regs are two new interfaces which allow
    presetting of a subset of eight x86 GPRs before executing the rd/wrmsr
    instructions. This is needed at least on AMD K8 for accessing an erratum
    workaround MSR.

    Originally based on an idea by H. Peter Anvin.