Hello,
I found an input which triggers an abort() in mch_update_pciexbar:
#0 0x00007ffff686d761 in __GI_raise (sig=sig@entry=0x6) at ../sysdeps/unix/sysv/linux/raise.c:50
#1 0x00007ffff685755b in __GI_abort () at abort.c:79
#2 0x000055555705c7ae in mch_update_pciexbar (mch=0x629000005920) at /home/alxndr/Development/qemu/hw/pci-host/q35.c:324
#3 0x000055555705bb6a in mch_write_config (d=0x629000005920, address=0x60, val=0x8400056e, len=0x4) at /home/alxndr/Development/qemu/hw/pci-host/q35.c:480
#4 0x00005555570954fb in pci_host_config_write_common (pci_dev=0x629000005920, addr=0x60, limit=0x100, val=0x8400056e, len=0x4) at /home/alxndr/Development/qemu/hw/pci/pci_host.c:81
#5 0x000055555709606e in pci_data_write (s=0x61d000096080, addr=0xf2000060, val=0x8400056e, len=0x4) at /home/alxndr/Development/qemu/hw/pci/pci_host.c:118
#6 0x00005555570967d0 in pci_host_data_write (opaque=0x629000005200, addr=0x0, val=0x8400056e, len=0x4) at /home/alxndr/Development/qemu/hw/pci/pci_host.c:165
#7 0x00005555564938b5 in memory_region_write_accessor (mr=0x629000005610, addr=0x0, value=0x7fffffff9c70, size=0x4, shift=0x0, mask=0xffffffff, attrs=...) at /home/alxndr/Development/qemu/memory.c:483
#8 0x000055555649328a in access_with_adjusted_size (addr=0x0, value=0x7fffffff9c70, size=0x4, access_size_min=0x1, access_size_max=0x4, access_fn=0x555556493360 <memory_region_write_accessor>, mr=0x629000005610, attrs=...) at /home/alxndr/Development/qemu/memory.c:544
#9 0x0000555556491df6 in memory_region_dispatch_write (mr=0x629000005610, addr=0x0, data=0x8400056e, op=MO_32, attrs=...) at /home/alxndr/Development/qemu/memory.c:1476
#10 0x00005555562cbbf4 in flatview_write_continue (fv=0x606000033b00, addr=0xcfc, attrs=..., ptr=0x7fffffffa4e0, len=0x4, addr1=0x0, l=0x4, mr=0x629000005610) at /home/alxndr/Development/qemu/exec.c:3137
#11 0x00005555562bbad9 in flatview_write (fv=0x606000033b00, addr=0xcfc, attrs=..., buf=0x7fffffffa4e0, len=0x4) at /home/alxndr/Development/qemu/exec.c:3177
#12 0x00005555562bb609 in address_space_write (as=0x55555968f940 <address_space_io>, addr=0xcfc, attrs=..., buf=0x7fffffffa4e0, len=0x4) at /home/alxndr/Development/qemu/exec.c:3268
#13 0x0000555556478c0a in cpu_outl (addr=0xcfc, val=0x8400056e) at /home/alxndr/Development/qemu/ioport.c:80
#14 0x000055555648166f in qtest_process_command (chr=0x555559691d00 <qtest_chr>, words=0x60300009ebf0) at /home/alxndr/Development/qemu/qtest.c:396
#15 0x000055555647f187 in qtest_process_inbuf (chr=0x555559691d00 <qtest_chr>, inbuf=0x61900000f680) at /home/alxndr/Development/qemu/qtest.c:710
#16 0x000055555647e8b4 in qtest_read (opaque=0x555559691d00 <qtest_chr>, buf=0x7fffffffca40 "outl 0xcf8 0xf2000060\noutl 0xcfc 0x8400056e\n-M pc-q35-5.0 -device intel-hda,id=hda0 -device hda-output,bus=hda0.0 -device hda-micro,bus=hda0.0 -device hda-duplex,bus=hda0.0 -display none -nodefaults -nographic\n\377\377\377\177", size=0xd2) at /home/alxndr/Development/qemu/qtest.c:722
#17 0x00005555579c260c in qemu_chr_be_write_impl (s=0x60f000001f30, buf=0x7fffffffca40 "outl 0xcf8 0xf2000060\noutl 0xcfc 0x8400056e\n-M pc-q35-5.0 -device intel-hda,id=hda0 -device hda-output,bus=hda0.0 -device hda-micro,bus=hda0.0 -device hda-duplex,bus=hda0.0 -display none -nodefaults -nographic\n\377\377\377\177", len=0xd2) at /home/alxndr/Development/qemu/chardev/char.c:183
#18 0x00005555579c275b in qemu_chr_be_write (s=0x60f000001f30, buf=0x7fffffffca40 "outl 0xcf8 0xf2000060\noutl 0xcfc 0x8400056e\n-M pc-q35-5.0 -device intel-hda,id=hda0 -device hda-output,bus=hda0.0 -device hda-micro,bus=hda0.0 -device hda-duplex,bus=hda0.0 -display none -nodefaults -nographic\n\377\377\377\177", len=0xd2) at /home/alxndr/Development/qemu/chardev/char.c:195
#19 0x00005555579cb97a in fd_chr_read (chan=0x6080000026a0, cond=G_IO_IN, opaque=0x60f000001f30) at /home/alxndr/Development/qemu/chardev/char-fd.c:68
#20 0x0000555557a530ea in qio_channel_fd_source_dispatch (source=0x60c00002ef00, callback=0x5555579cb540 <fd_chr_read>, user_data=0x60f000001f30) at /home/alxndr/Development/qemu/io/channel-watch.c:84
#21 0x00007ffff7ca8898 in g_main_context_dispatch () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#22 0x0000555557c10b85 in glib_pollfds_poll () at /home/alxndr/Development/qemu/util/main-loop.c:219
#23 0x0000555557c0f57e in os_host_main_loop_wait (timeout=0x0) at /home/alxndr/Development/qemu/util/main-loop.c:242
#24 0x0000555557c0f177 in main_loop_wait (nonblocking=0x0) at /home/alxndr/Development/qemu/util/main-loop.c:518
#25 0x000055555689fd1e in qemu_main_loop () at /home/alxndr/Development/qemu/softmmu/vl.c:1664
#26 0x0000555557a6a29d in main (argc=0x17, argv=0x7fffffffe148, envp=0x7fffffffe208) at /home/alxndr/Development/qemu/softmmu/main.c:49
I can reproduce this in qemu 5.0 built using these qtest commands:
cat << EOF | ./qemu-system-i386 \
-qtest stdio -nographic -monitor none -serial none \
-M pc-q35-5.0
outl 0xcf8 0xf2000060
outl 0xcfc 0x8400056e
EOF
Please let me know if I can provide any further info.
-Alex
Proposed fix:
https:/