On 17/04/2015 07:10, Wanpeng Li wrote: >> > >> >Before the change, if guest CR4.MCE==0, then the machine check is >> >escalated to Catastrophic Error (CATERR) and the machine dies. > Could you point out which section of SDM describes that the machine check > is escalated to a CATERR if CR4.MCE==0? It's under the description of "Interrupt 18--Machine-Check Exception (#MC)": The machine-check mechanism is enabled by setting the MCE flag in control register CR4. [...] If the machine-check mechanism is not enabled (the MCE flag in control register CR4 is clear), a machine-check exception causes the processor to enter the shutdown state. This of course also applies whenever the non-root mode CR4 (*not* the shadow CR4 in the VMCS!) has the MCE flag cleared. Paolo -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html