IPMMU_CTX_INVALID
memset(mmu->utlb_ctx, IPMMU_CTX_INVALID, mmu->features->num_utlbs);
if (mmu->utlb_ctx[i] == IPMMU_CTX_INVALID)
mmu->utlb_ctx[utlb] = IPMMU_CTX_INVALID;
mmu->utlb_ctx[utlb] = IPMMU_CTX_INVALID;