1 files changed, 48 insertions, 0 deletions
diff --git a/results/classifier/108/other/1060 b/results/classifier/108/other/1060
new file mode 100644
index 000000000..1c6752bea
--- /dev/null
+++ b/results/classifier/108/other/1060
@@ -0,0 +1,48 @@
+other: 0.662
+device: 0.604
+graphic: 0.540
+semantic: 0.443
+debug: 0.343
+vnc: 0.323
+PID: 0.230
+socket: 0.226
+performance: 0.190
+boot: 0.186
+network: 0.177
+permissions: 0.166
+files: 0.131
+KVM: 0.052
+
+RISC-V: mtval/stval is not correctly set to the instruction itself on illegal instructions
+Description of problem:
+QEMU 7.0 claims to support `stval`/`mtval` for illegal instructions, but `mtval`/`stval` is actually set to `0`
+Steps to reproduce:
+1. Assemble and link `mtval-illegal.elf`. The code simply sets up a trap handler and generates an illegal instruction exception
+
+2. Start QEMU with:
+
+  ```
+  qemu-system-riscv64 -cpu rv64,h=off -bios mtval-illegal.elf -nographic -icount shift=0 -s -S
+  ```
+
+3. Attach with GDB:
+
+  ```
+  gdb mtval-illegal.elf
+
+  # Within GDB
+  target extended-remote :1234
+  break trap
+  disp $mtval
+
+  # Keep single stepping until breakpoint
+  stepi
+  ```
+
+4. When control flow reaches `trap`, `mtval` is written with `0` instead of the encoding of `csrw time, x0` (`0xc0101073`)
+Additional information:
+Writing `0` to `mtval` on a illegal instruction trap is allowed by the specs, but since the [changelog of QEMU 7.0][changelog] says it should be supported, I would consider it a bug.
+
+[changelog]: https://wiki.qemu.org/ChangeLog/7.0#RISC-V
+
+I encountered this when trying to figure out why my program worked with QEMU 6 but breaks with QEMU 7. It's more complicated, but in that case I managed to get `mtval` written with neither `0` nor the actual illegal instruction, but a different illegal instruction. I will try gathering up all the dependencies and write down the steps to reproduce if needed and if I find the time.