- pages = MAX((entries * sizeof(uint64_t)) / getpagesize(), 1);
- pages = MAX(pow2ceil(pages) - 1, 1); /* Round up */
- create.levels = ctz64(pages) / 6 + 1;
-
- ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_CREATE, &create);
+ /* bits_total is number of "x" needed */
+ bits_total = ctz64(entries * sizeof(uint64_t));
+ /*
+ * bits_per_level is a safe guess of how much we can allocate per level:
+ * 8 is the current minimum for CONFIG_FORCE_MAX_ZONEORDER and MAX_ORDER
+ * is usually bigger than that.
+ * Below we look at getpagesize() as TCEs are allocated from system pages.
+ */
+ bits_per_level = ctz64(getpagesize()) + 8;
+ create.levels = bits_total / bits_per_level;
+ if (bits_total % bits_per_level) {
+ ++create.levels;
+ }
+ max_levels = (64 - create.page_shift) / ctz64(getpagesize());
+ for ( ; create.levels <= max_levels; ++create.levels) {
+ ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_TCE_CREATE, &create);
+ if (!ret) {
+ break;
+ }
+ }