From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:54510) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hGHML-0007mi-0C for qemu-devel@nongnu.org; Tue, 16 Apr 2019 02:14:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hGHMJ-0006zy-IK for qemu-devel@nongnu.org; Tue, 16 Apr 2019 02:14:20 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60220) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hGHMI-0006wR-Ls for qemu-devel@nongnu.org; Tue, 16 Apr 2019 02:14:19 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id F123C30832E8 for ; Tue, 16 Apr 2019 06:14:13 +0000 (UTC) From: Markus Armbruster References: <20190411152520.10061-1-armbru@redhat.com> <20190411152520.10061-10-armbru@redhat.com> <20190415154342.GM2852@work-vm> Date: Tue, 16 Apr 2019 08:14:12 +0200 In-Reply-To: <20190415154342.GM2852@work-vm> (David Alan Gilbert's message of "Mon, 15 Apr 2019 16:43:44 +0100") Message-ID: <871s228ojv.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PATCH 09/17] target: Simplify how the TARGET_cpu_list() print List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: qemu-devel@nongnu.org "Dr. David Alan Gilbert" writes: > * Markus Armbruster (armbru@redhat.com) wrote: >> The various TARGET_cpu_list() take an fprintf()-like callback and a >> FILE * to pass to it. Their callers (vl.c's main() via list_cpus(), >> bsd-user/main.c's main(), linux-user/main.c's main()) all pass >> fprintf() and stdout. Thus, the flexibility provided by the (rather >> tiresome) indirection isn't actually used. >> >> Drop the callback, and call qemu_fprintf() instead. > > Actually calling qemu_printf Typo, will fix. Thanks! >> Calling printf() would also work, but would make the code unsuitable >> for monitor context without making it simpler. > > Gernally OK; but just checking - are there any flag combos that will > mean this ends up with the result going down a monitor rather than > stdout, and will that upset something like libvirt that might be using > this to enumerate a cpu list? No. qemu_printf() prints to current monitor if we have one, else to stdout. Thus, it prints to stdout as long as !cur_mon. cur_mon is thread-local, and always set like this: Monitor *old_mon = cur_mon; cur_mon = ... non-null value ... ... do something ... cur-mon = old_mon; It's set and restored * in monitor_qmp_dispatch() around executing a QMP command * in monitor_read() around handling HMP input (this includes executing a command) * in qmp_human_monitor_command() around executing the HMP command (this is where monitors become nested) Therefore, cur_mon is null unless we're executing a QMP command, an HMP command, or are processing HMP input. Clearer now?