diff options
| author | Christian Krinitsin <mail@krinitsin.com> | 2025-05-30 16:52:07 +0200 |
|---|---|---|
| committer | Christian Krinitsin <mail@krinitsin.com> | 2025-05-30 16:52:17 +0200 |
| commit | 9260319e7411ff8281700a532caa436f40120ec4 (patch) | |
| tree | 2f6bfe5f3458dd49d328d3a9eb508595450adec0 /gitlab/issues_text/target_missing/host_missing/accel_missing/2971 | |
| parent | 225caa38269323af1bfc2daadff5ec8bd930747f (diff) | |
| download | qemu-analysis-9260319e7411ff8281700a532caa436f40120ec4.tar.gz qemu-analysis-9260319e7411ff8281700a532caa436f40120ec4.zip | |
gitlab scraper: download in toml and text format
Diffstat (limited to 'gitlab/issues_text/target_missing/host_missing/accel_missing/2971')
| -rw-r--r-- | gitlab/issues_text/target_missing/host_missing/accel_missing/2971 | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/gitlab/issues_text/target_missing/host_missing/accel_missing/2971 b/gitlab/issues_text/target_missing/host_missing/accel_missing/2971 new file mode 100644 index 000000000..6706be6f5 --- /dev/null +++ b/gitlab/issues_text/target_missing/host_missing/accel_missing/2971 @@ -0,0 +1,44 @@ +loongarch64 crashes caused by lenient instruction decoding of vldi and xvldi +Description of problem: +Lenient instruction decoding of `vldi` and `xvldi` leads to Qemu crashes. + +The decoding of `vldi` and `xvldi` instruction allows for instructions with illegal immediates. + +`target/loongarch/insns.decode`: + +``` +vldi 0111 00111110 00 ............. ..... @v_i13 +xvldi 0111 01111110 00 ............. ..... @v_i13 +``` + +This is considered in `target/loongarch/tcg/insn_trans/trans_vec.c.inc`: + +```C + /* + * imm bit [11:8] is mode, mode value is 0-12. + * other values are invalid. + */ +``` + +However, an assertion error is raised when this condition is violated and qemu crashes: + +``` +** +ERROR:target/loongarch/insn_trans/trans_vec.c.inc:3574:vldi_get_value: code should not be reached +Bail out! ERROR:target/loongarch/insn_trans/trans_vec.c.inc:3574:vldi_get_value: code should not be reached +``` + +On hardware (Loongson 3A5000), these instructions cause a SIGILL. +Steps to reproduce: +1. compile the `test_inv_vldi` test program for loongarch64 (see additional information) +2. run `qemu-loongarch64-static ./test_inv_vldi` +Additional information: +I will post a patch for this issue to the mailing list soon. + +`test_inv_vldi` source code: + +```C +int main(int argc, char** argv) { + asm volatile(".4byte 0x73e3a000"); +} +``` |