From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45499) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ejPtg-0004jl-2X for qemu-devel@nongnu.org; Wed, 07 Feb 2018 08:36:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ejPtb-000575-2w for qemu-devel@nongnu.org; Wed, 07 Feb 2018 08:36:24 -0500 References: <20180207121027.32466-1-lersek@redhat.com> From: Marcel Apfelbaum Message-ID: Date: Wed, 7 Feb 2018 15:35:44 +0200 MIME-Version: 1.0 In-Reply-To: <20180207121027.32466-1-lersek@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] pci-bridge/i82801b11: clear bridge registers on platform reset List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Laszlo Ersek , qemu devel list Cc: "Michael S. Tsirkin" , qemu-stable@nongnu.org Hi Laszlo, On 07/02/2018 14:10, Laszlo Ersek wrote: > The "i82801b11-bridge" device model is a descendant of "base-pci-bridge" > (TYPE_PCI_BRIDGE). However, unlike other similar devices, such as > > - pci-bridge, > - pcie-pci-bridge, > - PCIE Root Port, > - xio3130 switch upstream and downstream ports, > - dec-21154-p2p-bridge, > - pbm-bridge, > - xilinx-pcie-root, > > "i82801b11-bridge" does not clear the bridge specific registers at > platform reset. > > This is a problem because devices on "i82801b11-bridge" continue to > respond to config space cycles after platform reset, when addressed with > the bus number that was previously programmed into the secondary bus > number register of "i82801b11-bridge". This error breaks OVMF's search for > extra (PXB) root buses, for example. > Now I understand why we didn't catch the error until now. Nobody tried to use the pxb device with the dmi-pci bridge. > The device class reset method for "i82801b11-bridge" is currently NULL; This is sad, the device was always broken. > set it directly to pci_bridge_reset(), like the last three bridge models > in the above listing do. > Thanks for catching it! Reviewed-by: Marcel Apfelbaum Thanks, Marcel > Cc: "Michael S. Tsirkin" > Cc: Marcel Apfelbaum > Cc: qemu-stable@nongnu.org > Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1541839 > Signed-off-by: Laszlo Ersek > --- > hw/pci-bridge/i82801b11.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/hw/pci-bridge/i82801b11.c b/hw/pci-bridge/i82801b11.c > index cb522bf30c31..ebf7f5f0e81c 100644 > --- a/hw/pci-bridge/i82801b11.c > +++ b/hw/pci-bridge/i82801b11.c > @@ -98,6 +98,7 @@ static void i82801b11_bridge_class_init(ObjectClass *klass, void *data) > k->realize = i82801b11_bridge_realize; > k->config_write = pci_bridge_write_config; > dc->vmsd = &i82801b11_bridge_dev_vmstate; > + dc->reset = pci_bridge_reset; > set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories); > } > >