Messages in this thread | | | Date | Thu, 12 Jan 2012 17:46:36 -0800 | Subject | Re: x86, mce, Use user return notifier in mce | From | Tony Luck <> |
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On Thu, Jan 12, 2012 at 4:36 PM, Huang Ying <ying.huang@intel.com> wrote: > Replace the home-made TIF_MCE_NOTIFY based code in MCE with user > return notifier.
When I looked at this before, I found that the existing user return notifier had the meaning "call a function before THIS CPU returns to user space". Use in KVM was to update some MSR that needed adjustment before a cpu ran another user process.
The MCE code wanted something slightly different: "call a function before THIS PROCESS returns to user space". So my prototype code from last year made a whole new set of interfaces - similar in style to the user return notifier, but with the MCE semantics.
At first glance it looks like you are just using the user return notifier code (perhaps I'm mis-reading the diff?). This won't work - it's possible for a context switch, and then the process that hit the MCE may get moved to another cpu, when it will be run. Meanwhile we'll execute our function in the context of some other process.
-Tony
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