#370 Guest/Host serial ports no longer working

[AndrewB]

Host:
Linux, Fedora 10 2.6.27.9-159.fc10.x86_64 on Intel Core 2 Duo (Q6600) running KVM (kvm-74-10.fc10.x86_64)

Guest:
Windows XP Home, using qemu-kvm -M pc -m 768 -smp 2 -boot c -hda /home/vm/Windows_XP_Home.img -net nic,macaddr=00:16:3e:10:23:ee,vlan=0 -net user,vlan=0,script=,ifname=virbr0 -std-vga -soundhw es1370 -localtime -serial /dev/ttyS0

Error messages when quitting Guest OS:
kvm_run: Unknown error 524
kvm_run returned -524

Summary:
On Fedora 8 and Fedora 9 using KVM-65 and earlier, connections from Windows COM1 to /dev/ttyS0 worked. On Fedora 10 and KVM-74 serial connection between guest and host no longer works.

How to reproduce:
On host OS, use GTKTerm to access the serial port /dev/ttyS0 with a loopback adapter attached to the port. You will see characters echo'ed back.

On Guest OS, use option -serial stdio and Hyperterm to access COM1, and you will see characters from Hyperterm on the Host OS terminal that started qemu-kvm (so we know that the Guest OS can send data out of KVM).

On Fedora 10, if you regress to KVM-65 (from Fedora 9 repository), by:

rpm -e kvm-74-10.fc10.x86_64
rpm -ihv --force gnutls-2.0.4-2.fc9.x86_64.rpm
rpm -ihv kvm-65-1.fc9.x86_64.rpm

Now option -serial /dev/ttyS0 will operate as expected, and Hyperterm will see characters echo'ed from the loopback hardware.