运行` mprotect‘got错误：`qemu_mprotect__osdep: mprotect:许可拒绝

Question

我正在尝试在mac m1上做mit6.828实验室。安装riscv-tool-chain后，我尝试运行make qemu，这似乎是用来启动内核的，但一开始我得到了以下错误：

mkfs/mkfs fs.img README user/xargstest.sh user/_cat user/_echo user/_forktest user/_grep user/_init user/_kill user/_ln user/_ls user/_mkdir user/_rm user/_sh user/_stressfs user/_usertests user/_wc user/_zombie user/_cowtest user/_uthread user/_call user/_testsh user/_kalloctest user/_bcachetest user/_alloctest user/_bigfile
nmeta 46 (boot, super, log blocks 30 inode blocks 13, bitmap blocks 1) blocks 1954 total 2000
balloc: first 766 blocks have been allocated
balloc: write bitmap block at sector 45
qemu-system-riscv64 -machine virt -bios none -kernel kernel/kernel -m 128M -smp 1 -nographic -drive file=fs.img,if=none,format=raw,id=x0 -device virtio-blk-device,drive=x0,bus=virtio-mmio-bus.0
Could not allocate dynamic translator buffer
make: *** [qemu] Error 1

因此，我从github克隆qemu reposiroty以获得源代码，并检查版本到v5.1.0，然后从这个链接路径应用链接中提到的修补程序

配置run如下所示：

 ./configure --disable-kvm --disable-werror --prefix=/usr/local --target-list="riscv64-softmmu"`

make和make install似乎运行良好，但是当我再次在实验室执行make qemu时，出现了另一个错误，我仍然没有找到解决这个问题的方法：

qemu-system-riscv64 -machine virt -bios none -kernel kernel/kernel -m 128M -smp 3 -nographic -drive file=fs.img,if=none,format=raw,id=x0 -device virtio-blk-device,drive=x0,bus=virtio-mmio-bus.0
qemu-system-riscv64: qemu_mprotect__osdep: mprotect failed: Permission denied
**
ERROR:/Users/rezero/Desktop/6.828-note/qemus/qemu-5.1.0/tcg/tcg.c:733:tcg_region_init: assertion failed: (!rc)
Bail out! ERROR:/Users/rezero/Desktop/6.828-note/qemus/qemu-5.1.0/tcg/tcg.c:733:tcg_region_init: assertion failed: (!rc)
make: *** [qemu] Abort trap: 6

Answer 1

我试了很多次，因为我不熟悉qemu和macos。现在我得到了：

# modify /etc/paths 
/usr/bin
/bin
/usr/local/bin
/usr/sbin
/sbin

# modify .zshrc
export PATH="/opt/homebrew/bin:$PATH"
export PATH="$HOME/bin:/usr/local/bin:$PATH"
export PATH="$PATH:/usr/local/opt/riscv-gnu-toolchain/bin"

仍然不知道发生了什么，但事情似乎工作后，我应用了以下两个补丁。(确保在迭代时关闭Rosetta模式，仍然使用qemu 5.1.0)

patch1，您只需将cd下载到qemu目录中，然后命令如下：patch -p1 < ../patch/v2-tcg-Fix-execution-on-Apple-Silicon.patch

patch2只需两行，只需打开osdep.c文件并修改它。

应用上述修补程序之后，运行configure：

./configure --disable-kvm --disable-werror --prefix=/usr/local --target-list="riscv64-softmmu"

和make & make install

然后它起作用了，内核可以开始了。

Answer 2

@Rezero遵循您的步骤，您在编译时是否遇到过这样的错误：

 CC      hw/display/virtio-gpu-3d.o
hw/display/virtio-gpu-3d.c:149:41: error: variable has incomplete type 'struct virgl_renderer_resource_info'
    struct virgl_renderer_resource_info info;
                                        ^
hw/display/virtio-gpu-3d.c:149:12: note: forward declaration of 'struct virgl_renderer_resource_info'
    struct virgl_renderer_resource_info info;
           ^
hw/display/virtio-gpu-3d.c:167:15: error: implicit declaration of function 'virgl_renderer_resource_get_info' is invalid in C99 [-Werror,-Wimplicit-function-declaration]

Answer 3

它是macOS 11.2 mprotect bug，您可以修改qemu/tcg/tcg.c修复它，查看https://gitlab.com/qemu-project/qemu/-/commit/c118881ee607dcac。