On 12/12/19 01:29, Sean Christopherson wrote: >> */ >> -#define MMIO_SPTE_GEN_MASK GENMASK_ULL(18, 0) >> +#define MMIO_SPTE_GEN_MASK GENMASK_ULL(17, 0) >> >> #define MMIO_SPTE_GEN_LOW_START 3 >> #define MMIO_SPTE_GEN_LOW_END 11 >> #define MMIO_SPTE_GEN_LOW_MASK GENMASK_ULL(MMIO_SPTE_GEN_LOW_END, \ >> MMIO_SPTE_GEN_LOW_START) >> >> -#define MMIO_SPTE_GEN_HIGH_START 52 >> -#define MMIO_SPTE_GEN_HIGH_END 61 >> +/* Leave room for SPTE_SPECIAL_MASK. */ >> +#define MMIO_SPTE_GEN_HIGH_START PT64_SECOND_AVAIL_BITS_SHIFT > I'd rather have GEN_HIGH_START be an explicit bit number and then add > a BUILD_BUG_ON(GEN_HIGH_START < PT64_SECOND_AVAIL_BITS_SHIFT) to ensure > the MMIO gen doesn't overlap other stuff. That way we get a build error > if someone changes PT64_SECOND_AVAIL_BITS_SHIFT, otherwise the MMIO gen > will end up who knows where and probably overwrite NX or EPT.SUPPRESS_VE. > Fair enough. While at it I'll also add MMIO_SPTE_GEN_BITS ( MMIO_SPTE_GEN_LOW_END - MMIO_SPTE_GEN_LOW_START + 1 + MMIO_SPTE_GEN_HIGH_END - MMIO_SPTE_GEN_HIGH_START + 1) and use it in MMIO_SPTE_GEN_MASK. Paolo
