On Wed, May 04, 2011 at 12:48:20PM -0300, Marcelo Tosatti wrote:
> When we enable an NMI window, we ask for an IRET intercept, since
> the IRET re-enables NMIs.  However, the IRET intercept happens before
> the instruction executes, while the NMI window architecturally opens
> afterwards.
> 
> To compensate for this mismatch, we only open the NMI window in the
> following exit, assuming that the IRET has by then executed; however,
> this assumption is not always correct; we may exit due to a host interrupt
> or page fault, without having executed the instruction.
> 
> Fix by checking for forward progress by recording and comparing the IRET's
> rip.  This is somewhat of a hack, since an unchaging rip does not mean that
> no forward progress has been made, but is the simplest fix for now.
> 
> Signed-off-by: Avi Kivity <[email protected]>
> (cherry picked from commit 97ee7f21f2f06f336b3ef7cc4efd8ec88b4abbf7)

Huh?  That commit id is not in Linus's tree, where did you get it from?

confused,

greg k-h

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