[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 09/11] x86/xen: use capabilities instead of fake cpuid values for xsave
On 18/04/17 07:31, Juergen Gross wrote: > @@ -281,22 +274,24 @@ static bool __init xen_check_mwait(void) > return false; > #endif > } > -static void __init xen_init_cpuid_mask(void) > + > +static bool __init xen_check_xsave(void) > { > - unsigned int ax, bx, cx, dx; > - unsigned int xsave_mask; > + unsigned int err, eax, edx; > > - ax = 1; > - cx = 0; > - cpuid(1, &ax, &bx, &cx, &dx); > + /* Test OSXSAVE capability via xgetbv instruction. */ The code is fine, but this comment isn't going to be any help to people reading this code in 6 months time. How about this: "Xen 4.0 and older accidentally leaked the host XSAVE flag into guest view, despite not being able to support guests using the functionality. Probe for the actual availability of XSAVE by seeing whether xgetbv executes successfully or raises #UD." Everything else is fine, so Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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