uvm_physseg_get_highest_frame
avail_end = ctob(uvm_physseg_get_highest_frame());
paddr_t uvm_physseg_get_highest_frame(void);
ATF_CHECK_EQ(VALID_AVAIL_END_PFN_1 - 1, uvm_physseg_get_highest_frame());
ATF_CHECK_EQ(VALID_AVAIL_END_PFN_3 - 1, uvm_physseg_get_highest_frame());
ATF_CHECK_EQ(VALID_AVAIL_END_PFN_3 - 1, uvm_physseg_get_highest_frame());