On 14.09.2012 18:17, Michael Tokarev wrote: > On 04.09.2012 10:58, Michael Tokarev wrote: >> On 04.09.2012 10:53, Paolo Bonzini wrote: >>> Il 03/09/2012 20:13, Michael Tokarev ha scritto: >> [] >>>> qemu -nographic -kernel /boot/vmlinuz-$(uname -r) -append console=ttyS0 >>>> -serial pty >>>> >>>> This will hang with 100% CPU usage until something is sent >>>> to the pty. <Enter> key is enough. >> [] >>> Could it be this one? >>> >>> <http://permalink.gmane.org/gmane.comp.emulators.qemu/168209> >> >> Removing this "pending" initialization fixes this problem too. > > Actually it is not the same thing, and applying this path > does not solve the originak issue for me, neither does > updating to 1.2.0 help. > > But it looks like I wasn't correct with the initial diagnostic. > Qemu (either 1.1 or 1.2) just sleeps for a few moments (about > 2 seconds) after startup with my command line option, and I > thought it is stalled. > > The actual problem appears to be qemu-kvm-specific, it does not > affect qemu (with or without -enable-kvm). > > qemu-kvm -nographic -kernel /boot/vmlinuz-$(uname -r) -append console=ttyS0 > -serial pty > > This hangs till I send a char to the pty.
And it is even _more_ twisted than that. It depends on the timing. If I connect to the pty "too soon", it will not stall. But if I wait for ~2 seconds or more before connecting, both qemu and qemu-kvm (and so current qemu/master too) will hang, requiring a keypress on the pty for the guest to start booting. Hwell. /mjt
