[Qemu-devel] [PATCH 3/5] xen, gfx passthrough: create intel isa bridge

[Yang Zhang <yang.z.zhang@intel.com>]

From: Yang Zhang <yang.z.zhang@Intel.com>

ISA bridge is needed since Intel gfx drive will probe it instead
of Dev31:Fun0 to make graphics device passthrough work easy for VMM, that
only need to expose ISA bridge to let driver know the real hardware underneath.

The original patch is from Allen Kay [allen.m.kay@intel.com]

Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Cc: Allen Kay <allen.m.kay@intel.com>
---
 hw/xen/xen_pt_graphics.c |   71 ++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 71 insertions(+), 0 deletions(-)

diff --git a/hw/xen/xen_pt_graphics.c b/hw/xen/xen_pt_graphics.c
index 9ad8a74..54f16cf 100644
--- a/hw/xen/xen_pt_graphics.c
+++ b/hw/xen/xen_pt_graphics.c
@@ -162,3 +162,74 @@ out:
     free(bios);
     return rc;
 }
+
+static uint32_t isa_bridge_read_config(PCIDevice *d, uint32_t addr, int len)
+{
+    uint32_t v;
+
+    v = pci_default_read_config(d, addr, len);
+
+    return v;
+}
+
+static void isa_bridge_write_config(PCIDevice *d, uint32_t addr, uint32_t v,
+                                    int len)
+{
+    pci_default_write_config(d, addr, v, len);
+
+    return;
+}
+
+static void isa_bridge_class_init(ObjectClass *klass, void *data)
+{
+    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+
+    k->config_read = isa_bridge_read_config;
+    k->config_write = isa_bridge_write_config;
+
+    return;
+};
+
+typedef struct {
+    PCIDevice dev;
+} ISABridgeState;
+
+static TypeInfo isa_bridge_info = {
+    .name          = "inte-pch-isa-bridge",
+    .parent        = TYPE_PCI_DEVICE,
+    .instance_size = sizeof(ISABridgeState),
+    .class_init = isa_bridge_class_init,
+};
+
+static void xen_pt_graphics_register_types(void)
+{
+    type_register_static(&isa_bridge_info);
+}
+
+type_init(xen_pt_graphics_register_types)
+
+static int create_pch_isa_bridge(PCIBus *bus, XenHostPCIDevice *hdev)
+{
+    struct PCIDevice *dev;
+
+    char rid;
+
+    dev = pci_create(bus, PCI_DEVFN(0x1f, 0), "inte-pch-isa-bridge");
+    if (!dev) {
+        XEN_PT_LOG(dev, "fail to create PCH ISA bridge.\n");
+        return -1;
+    }
+
+    qdev_init_nofail(&dev->qdev);
+
+    pci_config_set_vendor_id(dev->config, hdev->vendor_id);
+    pci_config_set_device_id(dev->config, hdev->device_id);
+
+    xen_host_pci_get_block(hdev, PCI_REVISION_ID, (uint8_t *)&rid, 1);
+
+    pci_config_set_revision(dev->config, rid);
+    pci_config_set_class(dev->config, PCI_CLASS_BRIDGE_ISA);
+
+    XEN_PT_LOG(dev, "Intel PCH ISA bridge is created.\n");
+    return 0;
+}
-- 
1.7.1