Re: [Qemu-devel] [v8][RESEND][PATCH 08/10] xen, gfx passthrough: register a isa bridge

[Chen, Tiejun]

+static void
+xen_igd_passthrough_isa_bridge_create(XenPCIPassthroughState *s,
+                                      XenHostPCIDevice *dev)
+{
+    uint16_t gpu_dev_id;
+    PCIDevice *d = &s->dev;
+
+    if (!is_igd_vga_passthrough(dev)) {
+        return;
+    }

I would rather move the if into xen_pt_initfn, otherwise reading
xen_pt_initfn it looks like we are going to create an isa bridge
regardless.

This makes sense.



+    gpu_dev_id = dev->device_id;
+    igd_passthrough_isa_bridge_create(d->bus, gpu_dev_id);
+}
+
  /* init */

  static int xen_pt_initfn(PCIDevice *d)
@@ -725,6 +740,9 @@ static int xen_pt_initfn(PCIDevice *d)

I'd like to add something like,

if (!is_igd_vga_passthrough(&s->real_device)) {
    XEN_PT_ERR(d, "Need to enable igd-passthru if you're trying"
               " to passthrough IGD GFX.\n");
    xen_host_pci_device_put(&s->real_device); 

    return -1; 

        }

              xen_host_pci_device_put(&s->real_device);
              return -1;
          }
+
+        /* Register ISA bridge for passthrough GFX. */
+        xen_igd_passthrough_isa_bridge_create(s, &s->real_device);
      }

      /* Handle real device's MMIO/PIO BARs */
diff --git a/include/hw/xen/xen.h b/include/hw/xen/xen.h
index 4356af4..703148e 100644
--- a/include/hw/xen/xen.h
+++ b/include/hw/xen/xen.h
@@ -51,4 +51,5 @@ void xen_register_framebuffer(struct MemoryRegion *mr);
  #  define HVM_MAX_VCPUS 32
  #endif

+extern void igd_passthrough_isa_bridge_create(PCIBus *bus, uint16_t 
gpu_dev_id);
  #endif /* QEMU_HW_XEN_H */

Either static or extern. You probably want to drop this declaration.


I just guess you're confused between igd_passthrough_isa_bridge_create() 
and xen_igd_passthrough_isa_bridge_create(), or am I wrong?

Note igd_passthrough_isa_bridge_create() is defined in the pc_piix.c file.

Thanks
Tiejun