From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:36050) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TCXBL-0007vS-HC for qemu-devel@nongnu.org; Fri, 14 Sep 2012 10:47:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TCXBK-0002FR-9U for qemu-devel@nongnu.org; Fri, 14 Sep 2012 10:47:47 -0400 Received: from isrv.corpit.ru ([86.62.121.231]:50038) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TCXBK-0002FI-2W for qemu-devel@nongnu.org; Fri, 14 Sep 2012 10:47:46 -0400 Message-ID: <5053438F.9000601@msgid.tls.msk.ru> Date: Fri, 14 Sep 2012 18:47:43 +0400 From: Michael Tokarev MIME-Version: 1.0 References: <5044F367.5080300@msgid.tls.msk.ru> <5045A560.4080108@redhat.com> <5045A6AD.8030107@msgid.tls.msk.ru> <50533C73.2080901@msgid.tls.msk.ru> In-Reply-To: <50533C73.2080901@msgid.tls.msk.ru> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] apparently missing yet another notify_event() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Anthony Liguori , qemu-devel 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-$(uname -r) -append console=ttyS0 -serial pty >>>> >>>> This will hang with 100% CPU usage until something is sent >>>> to the pty. key is enough. >> [] >>> Could it be this one? >>> >>> >> >> Removing this "pending" initialization fixes this problem too. > > Actually it is not the same thing, and applying this path > does not solve the originak issue for me, neither does > updating to 1.2.0 help. > > But it looks like I wasn't correct with the initial diagnostic. > Qemu (either 1.1 or 1.2) just sleeps for a few moments (about > 2 seconds) after startup with my command line option, and I > thought it is stalled. > > The actual problem appears to be qemu-kvm-specific, it does not > affect qemu (with or without -enable-kvm). > > qemu-kvm -nographic -kernel /boot/vmlinuz-$(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