Re: [PATCH 0/1] plugins: add API to read guest CPU memory from hwaddr

[Alex Bennée]

Rowan Hart <rowanbhart@gmail.com> writes:

> This patch adds a single API function which allows reading from a guest
> CPU physical address.
>
> I don't know of a good way to add a self-contained test for this feature
> to tests/tcg/plugins, but I did come up with a small test case to
> demonstrate the functionality using peiyuanix/riscv-os:

We have bare metal system tests (hello and memory) for i386, alpha,
loongarch64, aarch64 and arm. If you fancy having a go at implementing a
boot.S for riscv64 that would be super helpful for the check-tcg tests
as a whole.

See:

  tests/tcg/i386/system/boot.S
  tests/tcg/alpha/system/boot.S
  tests/tcg/loongarch64/system/boot.S
  tests/tcg/aarch64/system/boot.S
  tests/tcg/x86_64/system/boot.S
  tests/tcg/arm/system/boot.S

for what is needed (basically a MMU-enabled flat memory map and some
sort of emit char helper, probably using semihosting in this case)

>
> First, grab and build the firmware code:
>
> curl -o firmware.S 
> https://raw.githubusercontent.com/peiyuanix/riscv-os/main/03-Bare-Metal-Hello-RISC-V/firmware.s
> curl -o firmware.x 
> https://raw.githubusercontent.com/peiyuanix/riscv-os/main/03-Bare-Metal-Hello-RISC-V/firmware.ld
> riscv64-linux-gnu-as firmware.S -o firmware.o
> riscv64-linux-gnu-ld -T firmware.x -o firmare firmware.o
> riscv64-linux-gnu-objcopy -O binary -S firmware firmware.bin
>
> Next, grab and build the plugin (just dumps from phys address on first
> instruction executed):
>
> curl -o dump-riscv-firmware.c 
> https://gist.githubusercontent.com/novafacing/5abc08052fab671a0fb26547810b4c55/raw/33772d614d6e36eae30e3405af34f149d7cc608b/dump-riscv-firmware.c
> gcc -rdynamic -shared -fPIC -Iinclude/qemu $(pkg-config --cflags --libs 
> glib-2.0) -o libdump-riscv-firmware.so dump-riscv-firmware.c
>
<snip>

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro