Messages in this thread |  | | | Date | Wed, 08 Apr 2009 09:11:55 -0700 | | From | "H. Peter Anvin" <> | | Subject | Re: [PATCH] do not keep interrupt window closed by sti in real mode |
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Glauber Costa wrote: > > I get the idea from the pseudocode in sti description. > It says: > IF PE = 0 (* Executing in real-address mode *) > THEN > IF <- 1; (* Set Interrupt Flag *) > ELSE (* Executing in protected mode or virtual-8086 mode *) > > There is no mention to any other activity besides setting the if flag.
But the same is true for the protected mode side of the instruction description!
> Also, sti is used extensively in many places like the linux kernel for the > guest, and it works just fine in kvm. So I was led to believe that real mode > in fact behaving differently.
The difference is that at least under current Intel VT, VT only handles protected mode -- the real mode runs purely in the interpreter.
> I'll take a look at avi's suggestion.
-hpa
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