[Qemu-devel] [PATCH] RFC: linux-user-i386: crash on cpuid

[Marc-André Lureau]

Running cpuid instructions with a simple run like:
i386-linux-user/qemu-i386 tests/tcg/sha1-i386

Results in the following assert:
 #0  0x00007ffff64246f5 in raise () from /lib64/libc.so.6
 #1  0x00007ffff64262fa in abort () from /lib64/libc.so.6
 #2  0x00007ffff7937ec5 in g_assertion_message () from /lib64/libglib-2.0.so.0
 #3  0x00007ffff7937f5a in g_assertion_message_expr () from 
/lib64/libglib-2.0.so.0
 #4  0x000055555561b54c in apicid_bitwidth_for_count (count=0) at 
/home/elmarco/src/qemu/include/hw/i386/topology.h:58
 #5  0x000055555561b58a in apicid_smt_width (nr_cores=0, nr_threads=0) at 
/home/elmarco/src/qemu/include/hw/i386/topology.h:67
 #6  0x000055555561b5c3 in apicid_core_offset (nr_cores=0, nr_threads=0) at 
/home/elmarco/src/qemu/include/hw/i386/topology.h:82
 #7  0x000055555561b5e3 in apicid_pkg_offset (nr_cores=0, nr_threads=0) at 
/home/elmarco/src/qemu/include/hw/i386/topology.h:89
 #8  0x000055555561dd86 in cpu_x86_cpuid (env=0x555557999550, index=4, count=3, 
eax=0x7fffffffcae8, ebx=0x7fffffffcaec, ecx=0x7fffffffcaf0, edx=0x7fffffffcaf4) 
at /home/elmarco/src/qemu/target-i386/cpu.c:2405
 #9  0x0000555555638e8e in helper_cpuid (env=0x555557999550) at 
/home/elmarco/src/qemu/target-i386/misc_helper.c:106
 #10 0x000055555599dc5e in static_code_gen_buffer ()
 #11 0x00005555555952f8 in cpu_tb_exec (cpu=0x5555579912d0, itb=0x7ffff4371ab0) 
at /home/elmarco/src/qemu/cpu-exec.c:166
 #12 0x0000555555595c8e in cpu_loop_exec_tb (cpu=0x5555579912d0, 
tb=0x7ffff4371ab0, last_tb=0x7fffffffd088, tb_exit=0x7fffffffd084, 
sc=0x7fffffffd0a0) at /home/elmarco/src/qemu/cpu-exec.c:517
 #13 0x0000555555595e50 in cpu_exec (cpu=0x5555579912d0) at 
/home/elmarco/src/qemu/cpu-exec.c:612
 #14 0x00005555555c065b in cpu_loop (env=0x555557999550) at 
/home/elmarco/src/qemu/linux-user/main.c:297
 #15 0x00005555555c25b2 in main (argc=2, argv=0x7fffffffd848, 
envp=0x7fffffffd860) at /home/elmarco/src/qemu/linux-user/main.c:4803

The fields are set in qemu_init_vcpu() with softmmu, but it's a stub
with linux-user.

Signed-off-by: Marc-André Lureau <address@hidden>
---
 target-i386/cpu.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 5a5299a..ce8f798 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -3097,7 +3097,10 @@ static void x86_cpu_realizefn(DeviceState *dev, Error 
**errp)
 
     mce_init(cpu);
 
-#ifndef CONFIG_USER_ONLY
+#ifdef CONFIG_USER_ONLY
+    cs->nr_cores = smp_cores;
+    cs->nr_threads = smp_threads;
+#else
     if (tcg_enabled()) {
         AddressSpace *newas = g_new(AddressSpace, 1);
 
-- 
2.10.0