e.g. $qemu-system-x86_64 -device port92 will report segment fault, for port92_write try a un-allocated assignment for a20_out. so check before this assignment.
Signed-off-by: liguang <lig.f...@cn.fujitsu.com> --- hw/i386/pc.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/hw/i386/pc.c b/hw/i386/pc.c index ed7d9ba..a0e8ee0 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -440,7 +440,8 @@ static void port92_write(void *opaque, hwaddr addr, uint64_t val, DPRINTF("port92: write 0x%02x\n", val); s->outport = val; - qemu_set_irq(*s->a20_out, (val >> 1) & 1); + if (s->a20_out) + qemu_set_irq(*s->a20_out, (val >> 1) & 1); if (val & 1) { qemu_system_reset_request(); } -- 1.7.2.5