Messages in this thread | | | Date | Tue, 29 Apr 2014 00:14:59 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] x86-64: espfix for 64-bit mode *PROTOTYPE* |
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On 04/28/2014 09:36 PM, H. Peter Anvin wrote: > > There are still things that need fixing: we need to go through the > espfix path even when returning from NMI/MC (which fortunately can't > nest with taking an NMI/MC on the espfix path itself, since in that case > we will have been interrupted while running in the kernel with a kernel > stack.) > > (Cc: Rostedt because of the NMI issue.) >
NMI is fine: we go through irq_return except for nested NMI. There are only three IRETs in the kernel (irq_return, nested_nmi_out, and the early trap handler) and all of them are good.
I think we just need to clean up the PV aspects of this and then we should be in good shape. I have done a bunch of cleanups to the development git tree.
I'm considering making 16-bit segment support a EXPERT config option for both 32- and 64-bit kernels, as it seems like a bit of a waste for embedded systems which don't need this kind of backward compatibility. Maybe that is something that can be left for someone else to implement if they feel like it.
-hpa
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