On 1 February 2012 12:11, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: > The obvious fix would be to test for the virt extensions in ID_PFR1 > before enabling KVM, and mask out the virt extensions from the same > register in the guest by trapping CP15-c0. But c0 is used by cache > maintenance operations, and trapping would lead to unacceptable > performance degradation. You can just set HCR.TID3 to get hyp traps on only the feature ID registers, right? (traps access to only ID_PFR0, ID_PFR1, ID_DFR0, ID_AFR0, ID_MMFR0, ID_MMFR1, ID_MMFR2, ID_MMFR3, ID_ISAR0, ID_ISAR1, ID_ISAR2, ID_ISAR3, ID_ISAR4, ID_ISAR5, MVFR0, and MVFR1, none of which should be on performance-critical paths I hope.) -- PMM -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
