On 22/06/2019 15:20, Mark Cave-Ayland wrote: > I've just given your tcg-ppc-vsx branch a spin here, and like Howard I'm > getting > segfaults trying to launch my MacOS images :( The segfault is weird: it > doesn't get > caught by an attached gdb and the qemu-system-ppc process seems to hang > around like a > zombie which makes me think that it's probably an illegal instruction of some > kind, > but the PPC kernel can't handle it as well as x86 does. > > With a bit more work I bisected it down to the first commit in the patchset > (d8dcbb57e9: "tcg/ppc: Initial backend support for Altivec") and then as an > experiment I hacked tcg_can_emit_vec_op() to always return 0 to see if that > made a > difference, but the segfault still appears. > > The commit message mentions that the load and store helpers are also > improved, so I > wonder if they are what is causing the error rather than the vector parts? > Also in > the kernel log I see the following messages appearing: > > [3639669.374942] qemu-system-ppc[28591]: segfault (11) at 64b8 nip f87280 lr > f8723c > code 1 in qemu-system-ppc[94e000+aa0000] > [3639669.380015] qemu-system-ppc[28591]: code: 93c10038 91810020 90010044 > 7fc802a6 > 3fde0059 2e030000 3bde6c18 7c9d2378 > [3639669.385056] qemu-system-ppc[28591]: code: 813e80a0 7cbb2b78 7cda3378 > 7cf93b78 > <81428ff8> 9141001c 39400000 81290000 > > Does that help at all? If not let me know if there are any other tests that > you'd > like me to try to help debug this.
One more hint: if I try a build of d8dcbb57e9 along with my tcg_can_emit_vec_op() hack and pass --enable-debug-tcg to configure then I get an assert on startup: qemu-system-ppc: /home/mca/src/qemu/tcg/tcg.c:2207: process_op_defs: Assertion `tdefs != ((void *)0)' failed. Aborted ATB, Mark.
