From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43828) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XqFW6-0007dp-40 for qemu-devel@nongnu.org; Mon, 17 Nov 2014 01:10:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XqFW0-0005IZ-JY for qemu-devel@nongnu.org; Mon, 17 Nov 2014 01:10:26 -0500 Received: from mx1.redhat.com ([209.132.183.28]:51419) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XqFW0-0005IT-CI for qemu-devel@nongnu.org; Mon, 17 Nov 2014 01:10:20 -0500 Date: Mon, 17 Nov 2014 08:10:10 +0200 From: "Michael S. Tsirkin" Message-ID: <20141117061010.GB19718@redhat.com> References: <1415172179-7965-1-git-send-email-tiejun.chen@intel.com> <1415172179-7965-2-git-send-email-tiejun.chen@intel.com> <20141105140906.GA4912@redhat.com> <546961DC.4040300@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <546961DC.4040300@intel.com> Subject: Re: [Qemu-devel] [RFC][PATCH 2/2] xen:i386:pc_piix: create isa bridge specific to IGD passthrough List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Chen, Tiejun" Cc: xen-devel@lists.xensource.com, allen.m.kay@intel.com, qemu-devel@nongnu.org, aliguori@amazon.com, pbonzini@redhat.com, rth@twiddle.net On Mon, Nov 17, 2014 at 10:47:56AM +0800, Chen, Tiejun wrote: > On 2014/11/5 22:09, Michael S. Tsirkin wrote: > >On Wed, Nov 05, 2014 at 03:22:59PM +0800, Tiejun Chen wrote: > >>Currently IGD drivers always need to access PCH by 1f.0, and > >>PCH vendor/device id is used to identify the card. > >> > >>Signed-off-by: Tiejun Chen > >>--- > >> hw/i386/pc_piix.c | 28 +++++++++++++++++++++++++++- > >> 1 file changed, 27 insertions(+), 1 deletion(-) > >> > >>diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c > >>index b559181..b19c7a9 100644 > >>--- a/hw/i386/pc_piix.c > >>+++ b/hw/i386/pc_piix.c > >>@@ -50,7 +50,7 @@ > >> #include "cpu.h" > >> #include "qemu/error-report.h" > >> #ifdef CONFIG_XEN > >>-# include > >>+#include > >> #endif > >> > >> #define MAX_IDE_BUS 2 > >>@@ -452,6 +452,31 @@ static void pc_init_isa(MachineState *machine) > >> } > >> > >> #ifdef CONFIG_XEN > >>+static void xen_igd_passthrough_isa_bridge_create(PCIBus *bus) > >>+{ > >>+ struct PCIDevice *dev; > >>+ Error *local_err = NULL; > >>+ uint16_t device_id = 0xffff; > >>+ > >>+ /* Currently IGD drivers always need to access PCH by 1f.0. */ > >>+ dev = pci_create_simple(bus, PCI_DEVFN(0x1f, 0), > >>+ "xen-igd-passthrough-isa-bridge"); > >>+ > >>+ /* Identify PCH card with its own real vendor/device ids. > >>+ * Here that vendor id is always PCI_VENDOR_ID_INTEL. > >>+ */ > >>+ if (dev) { > >>+ device_id = object_property_get_int(OBJECT(dev), "device-id", > >>+ &local_err); > >>+ if (!local_err && device_id != 0xffff) { > >>+ pci_config_set_device_id(dev->config, device_id); > >>+ return; > >>+ } > >>+ } > >>+ > >>+ fprintf(stderr, "xen set xen-igd-passthrough-isa-bridge failed\n"); > >>+} > >>+ > >> static void pc_xen_hvm_init(MachineState *machine) > >> { > >> PCIBus *bus; > >>@@ -461,6 +486,7 @@ static void pc_xen_hvm_init(MachineState *machine) > >> bus = pci_find_primary_bus(); > >> if (bus != NULL) { > >> pci_create_simple(bus, -1, "xen-platform"); > >>+ xen_igd_passthrough_isa_bridge_create(bus); > >> } > >> } > >> #endif > > > >Can't we defer this step until the GPU is added? > > Sounds great but I can't figure out where we can to do this exactly. > > >This way there won't be need to poke at host device > >directly, you could get all info from dev->config > >of the host device. > > As I understand We have two steps here: > > #1 At first I have to write something to check if we're registering 00:02.0 > & IGD, right? But where? While registering each pci device? In xen_pt_initfn. Just check the device and vendor ID against the table you have. > #2 Then if that condition is matched, we register this ISA bridge on its > associated bus. > > Thanks > Tiejun Yep. > >Additionally the correct bridge would be initialized automatically. > > > > > >>-- > >>1.9.1 > >