Hi,
I found this bug when testing my avocado changes in riscv-to-apply.next.
The sifive_u board, both 32 and 64 bits, stopped booting OpenSBI. The
guest hangs indefinitely.
Git bisect points that this patch broke things:
8c3f35d25e7e98655c609b6c1e9f103b9240f8f8 is the first bad commit
commit 8c3f35d25e7e98655c609b6c1e9f103b9240f8f8
Author: Weiwei Li <liwei...@iscas.ac.cn>
Date: Wed Dec 28 14:20:21 2022 +0800
target/riscv: add support for Zca extension
Modify the check for C extension to Zca (C implies Zca)
(https://github.com/alistair23/qemu/commit/8c3f35d25e7e98655c609b6c1e9f103b9240f8f8)
But this patch per se isn't doing anything wrong. The root of the
problem is that this patch makes assumptions based on the previous
patch:
commit a2b409aa6cadc1ed9715e1ab916ddd3dade0ba85
Author: Weiwei Li <liwei...@iscas.ac.cn>
Date: Wed Dec 28 14:20:20 2022 +0800
target/riscv: add cfg properties for Zc* extension
(https://github.com/alistair23/qemu/commit/a2b409aa6cadc1ed9715e1ab916ddd3dade0ba85)
Which added a lot of logic and assumptions that are being skipped by all
the SiFive boards because, during riscv_cpu_realize(), we have this
code:
/* If only MISA_EXT is unset for misa, then set it from properties */
if (env->misa_ext == 0) {
uint32_t ext = 0;
(...)
}
In short, we have a lot of code that are being skipped by all SiFive
CPUs because these CPUs are setting a non-zero value in set_misa() in
their respective cpu_init() functions.
It's possible to just hack in and fix the SiFive problem in isolate, but
I believe we can do better and allow all riscv_cpu_realize() to be executed
for all CPUs, regardless of what they've done during their cpu_init().
Daniel Henrique Barboza (2):
target/riscv/cpu: set cpu->cfg in register_cpu_props()
target/riscv/cpu.c: do not skip misa logic in riscv_cpu_realize()
target/riscv/cpu.c | 525 +++++++++++++++++++++++++--------------------
target/riscv/cpu.h | 4 +
2 files changed, 292 insertions(+), 237 deletions(-)
--
2.39.0
