From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:37074) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ri5ku-0002JV-Hx for qemu-devel@nongnu.org; Tue, 03 Jan 2012 09:54:25 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ri5kl-0000ZI-CQ for qemu-devel@nongnu.org; Tue, 03 Jan 2012 09:54:24 -0500 Received: from cantor2.suse.de ([195.135.220.15]:40907 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ri5kl-0000Z4-3o for qemu-devel@nongnu.org; Tue, 03 Jan 2012 09:54:15 -0500 From: Alexander Graf Date: Tue, 3 Jan 2012 16:08:19 +0100 Message-Id: <1325603302-12412-8-git-send-email-agraf@suse.de> In-Reply-To: <1325603302-12412-1-git-send-email-agraf@suse.de> References: <1325603302-12412-1-git-send-email-agraf@suse.de> Subject: [Qemu-devel] [PATCH 07/10] pseries: Add a routine to find a stable "default" vty and use it List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "qemu-devel@nongnu.org Developers" Cc: Blue Swirl , Michael Ellerman , Aurelien Jarno , David Gibson From: David Gibson In vty_lookup() we have a special case for supporting early debug in the kernel. This accepts reg == 0 as a special case to mean "any vty". We implement this by searching the vtys on the bus and returning the first we find. This means that the vty we chose depends on the order the vtys are specified on the QEMU command line - because that determines the order of the vtys on the bus. We'd rather the command line order was irrelevant, so instead return the vty with the lowest reg value. This is still a guess as to what the user really means, but it is at least stable WRT command line ordering. Signed-off-by: Michael Ellerman Signed-off-by: David Gibson Signed-off-by: Alexander Graf [agraf] fix braces --- hw/spapr_vty.c | 47 ++++++++++++++++++++++++++++++++++++++--------- 1 files changed, 38 insertions(+), 9 deletions(-) diff --git a/hw/spapr_vty.c b/hw/spapr_vty.c index e217314..2923ca7 100644 --- a/hw/spapr_vty.c +++ b/hw/spapr_vty.c @@ -149,24 +149,53 @@ static VIOsPAPRDeviceInfo spapr_vty = { }, }; +static VIOsPAPRDevice *spapr_vty_get_default(VIOsPAPRBus *bus) +{ + VIOsPAPRDevice *sdev, *selected; + DeviceState *iter; + + /* + * To avoid the console bouncing around we want one VTY to be + * the "default". We haven't really got anything to go on, so + * arbitrarily choose the one with the lowest reg value. + */ + + selected = NULL; + QTAILQ_FOREACH(iter, &bus->bus.children, sibling) { + /* Only look at VTY devices */ + if (iter->info != &spapr_vty.qdev) { + continue; + } + + sdev = DO_UPCAST(VIOsPAPRDevice, qdev, iter); + + /* First VTY we've found, so it is selected for now */ + if (!selected) { + selected = sdev; + continue; + } + + /* Choose VTY with lowest reg value */ + if (sdev->reg < selected->reg) { + selected = sdev; + } + } + + return selected; +} + static VIOsPAPRDevice *vty_lookup(sPAPREnvironment *spapr, target_ulong reg) { VIOsPAPRDevice *sdev; sdev = spapr_vio_find_by_reg(spapr->vio_bus, reg); if (!sdev && reg == 0) { - DeviceState *qdev; - /* Hack for kernel early debug, which always specifies reg==0. - * We search all VIO devices, and grab the first available vty - * device. This attempts to mimic existing PowerVM behaviour + * We search all VIO devices, and grab the vty with the lowest + * reg. This attempts to mimic existing PowerVM behaviour * (early debug does work there, despite having no vty with * reg==0. */ - QTAILQ_FOREACH(qdev, &spapr->vio_bus->bus.children, sibling) { - if (qdev->info == &spapr_vty.qdev) { - return DO_UPCAST(VIOsPAPRDevice, qdev, qdev); - } - } + return spapr_vty_get_default(spapr->vio_bus); } return sdev; -- 1.6.0.2