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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Re: [PATCH] [RFC] More fp instructions for realmode emulation (Enables booting OS/2 as a HVM guest on Intel/VT hardware)
On 3/3/08 16:59, "Andi Kleen" <andi@xxxxxxxxxxxxxx> wrote: >>> Yes you definitely need to. That was a kernel crash bug on native Linux >>> some time ago... >>> >>> Also you need to do the same for any FXSAVEs/FXRSTORs if you haven't >>> already. >> >> FXSAVE/FXRSTOR do not flush pending FPU exceptions, right? > > Yes they do not, but there are other ways to make them #GP We don't trust FXRSTOR but we do trust FXSAVE. The AMD manual says that FXRSTOR will #GP if 1s are written to MXCSR reserved bits, but I take this to be a cut-and-paste typo since FXSAVE does not write to MXCSR. If there's real evidence of FXSAVE causing #GP dependent on current FPU state, I'd be very happy to find out about it! -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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