看代码并加上中文注释，还有就是做lab
代码基于2020 MIT 6.S081的xv6-riscv，lab也基于此
我只在macos intel x86调试，所以下面环境就是macos环境要安装的，brew自行安装吧😄
$ brew tap riscv/riscv
$ brew install riscv-tools
重新配置下PATH环境变量，把riscv工具相关二进制加入到PATH
PATH=$PATH:/usr/local/opt/riscv-gnu-toolchain/bin
最后安装qemu
brew install qemu
原来xv6的代码在最新qemu里面起来卡住，改了些代码后可以启动，
所以不知道后面更新的qemu是否还能启动，
所以记下现在运行的版本：
$ riscv64-unknown-elf-gcc --version
riscv64-unknown-elf-gcc (GCC) 10.2.0
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ qemu-system-riscv64 --version
QEMU emulator version 6.0.0
Copyright (c) 2003-2021 Fabrice Bellard and the QEMU Project developers
$ make qemu
ctrl+a,松开,按x
$ usertests # 进入系统后执行, 会运行很多测试，回归测试必用
这个lab跟原来的不同，是每个lab是基于上个lab基础继续做的，所以这样最后代码就基本是所有lab的集合，很有挑战哈
每个lab跑测试之前最好清空下文件
$ make clean
$ ./grade-lab-util
make: `kernel/kernel' is up to date.
== Test sleep, no arguments == sleep, no arguments: OK (1.8s)
== Test sleep, returns == sleep, returns: OK (0.7s)
== Test sleep, makes syscall == sleep, makes syscall: OK (0.9s)
== Test pingpong == pingpong: OK (1.0s)
== Test primes == primes: OK (1.0s)
== Test find, in current directory == find, in current directory: OK (1.2s)
== Test find, recursive == find, recursive: OK (1.6s)
== Test xargs == xargs: OK (1.5s)
== Test time ==
time: OK
Score: 100/100
$ ./grade-lab-syscall
make: `kernel/kernel' is up to date.
== Test trace 32 grep == trace 32 grep: OK (1.5s)
== Test trace all grep == trace all grep: OK (0.8s)
== Test trace nothing == trace nothing: OK (1.1s)
== Test trace children == trace children: OK (15.1s)
== Test sysinfotest == sysinfotest: OK (2.5s)
== Test time ==
time: OK
Score: 35/35
$ LAB=pgtbl ./grade-lab-pgtbl
make: `kernel/kernel' is up to date.
== Test pte printout == pte printout: OK (0.9s)
== Test answers-pgtbl.txt == answers-pgtbl.txt: OK
== Test count copyin == count copyin: OK (0.9s)
== Test usertests == (287.8s)
== Test usertests: copyin ==
usertests: copyin: OK
== Test usertests: copyinstr1 ==
usertests: copyinstr1: OK
== Test usertests: copyinstr2 ==
usertests: copyinstr2: OK
== Test usertests: copyinstr3 ==
usertests: copyinstr3: OK
== Test usertests: sbrkmuch ==
usertests: sbrkmuch: OK
== Test usertests: all tests ==
usertests: all tests: OK
== Test time ==
time: OK
Score: 66/66
$ LAB=traps ./grade-lab-traps
make: `kernel/kernel' is up to date.
== Test answers-traps.txt == answers-traps.txt: OK
== Test backtrace test == backtrace test: OK (1.1s)
== Test running alarmtest == (4.5s)
== Test alarmtest: test0 ==
alarmtest: test0: OK
== Test alarmtest: test1 ==
alarmtest: test1: OK
== Test alarmtest: test2 ==
alarmtest: test2: OK
== Test usertests == usertests: OK (305.4s)
(Old xv6.out.usertests failure log removed)
== Test time ==
time: OK
Score: 85/85
$ ./grade-lab-lazy
make: `kernel/kernel' is up to date.
== Test running lazytests == (1.6s)
== Test lazy: map ==
lazy: map: OK
== Test lazy: unmap ==
lazy: unmap: OK
== Test usertests == (230.8s)
== Test usertests: pgbug ==
usertests: pgbug: OK
== Test usertests: sbrkbugs ==
usertests: sbrkbugs: OK
== Test usertests: argptest ==
usertests: argptest: OK
== Test usertests: sbrkmuch ==
usertests: sbrkmuch: OK
== Test usertests: sbrkfail ==
usertests: sbrkfail: OK
== Test usertests: sbrkarg ==
usertests: sbrkarg: OK
== Test usertests: stacktest ==
usertests: stacktest: OK
== Test usertests: execout ==
usertests: execout: OK
== Test usertests: copyin ==
usertests: copyin: OK
== Test usertests: copyout ==
usertests: copyout: OK
== Test usertests: copyinstr1 ==
usertests: copyinstr1: OK
== Test usertests: copyinstr2 ==
usertests: copyinstr2: OK
== Test usertests: copyinstr3 ==
usertests: copyinstr3: OK
== Test usertests: rwsbrk ==
usertests: rwsbrk: OK
== Test usertests: truncate1 ==
usertests: truncate1: OK
== Test usertests: truncate2 ==
usertests: truncate2: OK
== Test usertests: truncate3 ==
usertests: truncate3: OK
== Test usertests: reparent2 ==
usertests: reparent2: OK
== Test usertests: badarg ==
usertests: badarg: OK
== Test usertests: reparent ==
usertests: reparent: OK
== Test usertests: twochildren ==
usertests: twochildren: OK
== Test usertests: forkfork ==
usertests: forkfork: OK
== Test usertests: forkforkfork ==
usertests: forkforkfork: OK
== Test usertests: createdelete ==
usertests: createdelete: OK
== Test usertests: linkunlink ==
usertests: linkunlink: OK
== Test usertests: linktest ==
usertests: linktest: OK
== Test usertests: unlinkread ==
usertests: unlinkread: OK
== Test usertests: concreate ==
usertests: concreate: OK
== Test usertests: subdir ==
usertests: subdir: OK
== Test usertests: fourfiles ==
usertests: fourfiles: OK
== Test usertests: sharedfd ==
usertests: sharedfd: OK
== Test usertests: exectest ==
usertests: exectest: OK
== Test usertests: bigargtest ==
usertests: bigargtest: OK
== Test usertests: bigwrite ==
usertests: bigwrite: OK
== Test usertests: bsstest ==
usertests: bsstest: OK
== Test usertests: sbrkbasic ==
usertests: sbrkbasic: OK
== Test usertests: kernmem ==
usertests: kernmem: OK
== Test usertests: validatetest ==
usertests: validatetest: OK
== Test usertests: opentest ==
usertests: opentest: OK
== Test usertests: writetest ==
usertests: writetest: OK
== Test usertests: writebig ==
usertests: writebig: OK
== Test usertests: createtest ==
usertests: createtest: OK
== Test usertests: openiput ==
usertests: openiput: OK
== Test usertests: exitiput ==
usertests: exitiput: OK
== Test usertests: iput ==
usertests: iput: OK
== Test usertests: mem ==
usertests: mem: OK
== Test usertests: pipe1 ==
usertests: pipe1: OK
== Test usertests: preempt ==
usertests: preempt: OK
== Test usertests: exitwait ==
usertests: exitwait: OK
== Test usertests: rmdot ==
usertests: rmdot: OK
== Test usertests: fourteen ==
usertests: fourteen: OK
== Test usertests: bigfile ==
usertests: bigfile: OK
== Test usertests: dirfile ==
usertests: dirfile: OK
== Test usertests: iref ==
usertests: iref: OK
== Test usertests: forktest ==
usertests: forktest: OK
== Test time ==
time: OK
Score: 119/119
$ ./grade-lab-cow
== Test running cowtest == (11.4s)
== Test simple ==
simple: OK
== Test three ==
three: OK
== Test file ==
file: OK
== Test usertests == (192.0s)
== Test usertests: copyin ==
usertests: copyin: OK
== Test usertests: copyout ==
usertests: copyout: OK
== Test usertests: all tests ==
usertests: all tests: OK
== Test time ==
time: OK
Score: 110/110
$ ./grade-lab-thread
== Test uthread == uthread: OK (7.0s)
== Test answers-thread.txt == answers-thread.txt: OK
== Test ph_safe == gcc -o ph -g -O2 notxv6/ph.c -pthread
ph_safe: OK (8.9s)
== Test ph_fast == make: `ph' is up to date.
ph_fast: OK (18.1s)
== Test barrier == gcc -o barrier -g -O2 notxv6/barrier.c -pthread
barrier: OK (2.3s)
== Test time ==
time: OK
Score: 60/60
$ LAB=lock ./grade-lab-lock
make: `kernel/kernel' is up to date.
== Test running kalloctest == (413.1s)
== Test kalloctest: test1 ==
kalloctest: test1: OK
== Test kalloctest: test2 ==
kalloctest: test2: OK
== Test kalloctest: sbrkmuch == kalloctest: sbrkmuch: OK (18.8s)
== Test running bcachetest == (16.6s)
== Test bcachetest: test0 ==
bcachetest: test0: OK
== Test bcachetest: test1 ==
bcachetest: test1: OK
== Test usertests == usertests: OK (244.3s)
== Test time ==
time: OK
Score: 70/70
$ ./grade-lab-fs
== Test running bigfile == running bigfile: OK (636.2s)
== Test running symlinktest == (3.1s)
== Test symlinktest: symlinks ==
symlinktest: symlinks: OK
== Test symlinktest: concurrent symlinks ==
symlinktest: concurrent symlinks: OK
== Test usertests == usertests: OK (1362.6s)
== Test time ==
time: OK
Score: 100/100
$ ./grade-lab-mmap
== Test running mmaptest == (12.3s)
== Test mmaptest: mmap f ==
mmaptest: mmap f: OK
== Test mmaptest: mmap private ==
mmaptest: mmap private: OK
== Test mmaptest: mmap read-only ==
mmaptest: mmap read-only: OK
== Test mmaptest: mmap read/write ==
mmaptest: mmap read/write: OK
== Test mmaptest: mmap dirty ==
mmaptest: mmap dirty: OK
== Test mmaptest: not-mapped unmap ==
mmaptest: not-mapped unmap: OK
== Test mmaptest: two files ==
mmaptest: two files: OK
== Test mmaptest: fork_test ==
mmaptest: fork_test: OK
== Test usertests == usertests: OK (834.4s)
== Test time ==
time: OK
Score: 140/140
在一个窗口运行
$ make server
python3 server.py 25600
listening on localhost port 25600
在另一个窗口运行
$ ./grade-lab-net
make: `kernel/kernel' is up to date.
== Test running nettests == (3.9s)
== Test nettest: ping ==
nettest: ping: OK
== Test nettest: single process ==
nettest: single process: OK
== Test nettest: multi-process ==
nettest: multi-process: OK
== Test nettest: DNS ==
nettest: DNS: OK
== Test time ==
time: OK
Score: 100/100
- 由于内核页表，延迟加载页和fork的copy on write这几个实验，造成了系统调用实验里面
sysinfotest里面测试testmem兼容不了了，所以我注释这部分测试 - 由于文件系统实验引入了大文件的支持，令
usertests执行非常慢，我机子要差不多20几分钟，如果调试可以把writebig这个测试注释掉
https://pdos.csail.mit.edu/6.828/2020/xv6.html