From: ddugger@redhat.com <ddugger@redhat.com>
Date: Mon, 6 Apr 2009 15:51:44 -0600
Subject: [pci] xen dom0: hook PCI probe and remove callbacks
Message-id: 200904062151.n36Lpila013514@sobek.n0ano.com
O-Subject: [RHEL5.4 PATCH 3/3] BZ484227: VTD: dom0: hook Linux's PCI probe and remove callbacks
Bugzilla: 484227
RH-Acked-by: Gerd Hoffmann <kraxel@redhat.com>

Hijack the pci_bus_type probe and remove callbacks.  This option only
requires modification to the Xen specific part of Linux.

Upstream Status: Accepted (CS 593)

Signed-off-by: Joshua LeVasseur <joshua.levasseur@netronome.com>
Signed-off-by: Weidong Han <weidong.han@intel.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Don Dugger <donald.d.dugger@intel.com>

diff --git a/drivers/xen/core/Makefile b/drivers/xen/core/Makefile
index 82ec8e7..2992020 100644
--- a/drivers/xen/core/Makefile
+++ b/drivers/xen/core/Makefile
@@ -4,6 +4,7 @@
 
 obj-y := evtchn.o gnttab.o features.o
 
+obj-$(CONFIG_PCI)		    += pci.o
 obj-$(CONFIG_PROC_FS)		+= xen_proc.o
 obj-$(CONFIG_SYSFS)		+= hypervisor_sysfs.o
 obj-$(CONFIG_HOTPLUG_CPU)	+= cpu_hotplug.o
diff --git a/drivers/xen/core/pci.c b/drivers/xen/core/pci.c
new file mode 100644
index 0000000..57bcf84
--- /dev/null
+++ b/drivers/xen/core/pci.c
@@ -0,0 +1,59 @@
+/*
+ * vim:shiftwidth=8:noexpandtab
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <xen/interface/physdev.h>
+
+static int (*pci_bus_probe)(struct device *dev);
+static int (*pci_bus_remove)(struct device *dev);
+
+static int pci_bus_probe_wrapper(struct device *dev)
+{
+	int r;
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct physdev_manage_pci manage_pci;
+	manage_pci.bus = pci_dev->bus->number;
+	manage_pci.devfn = pci_dev->devfn;
+
+	r = HYPERVISOR_physdev_op(PHYSDEVOP_manage_pci_add, &manage_pci);
+	if (r && r != -ENOSYS)
+		return r;
+
+	r = pci_bus_probe(dev);
+	return r;
+}
+
+static int pci_bus_remove_wrapper(struct device *dev)
+{
+	int r;
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct physdev_manage_pci manage_pci;
+	manage_pci.bus = pci_dev->bus->number;
+	manage_pci.devfn = pci_dev->devfn;
+
+	r = pci_bus_remove(dev);
+	/* dev and pci_dev are no longer valid!! */
+
+	WARN_ON(HYPERVISOR_physdev_op(PHYSDEVOP_manage_pci_remove,
+		&manage_pci));
+	return r;
+}
+
+static int __init hook_pci_bus(void)
+{
+	if (!is_running_on_xen() || !is_initial_xendomain())
+		return 0;
+
+	pci_bus_probe = pci_bus_type.probe;
+	pci_bus_type.probe = pci_bus_probe_wrapper;
+
+	pci_bus_remove = pci_bus_type.remove;
+	pci_bus_type.remove = pci_bus_remove_wrapper;
+
+	return 0;
+}
+
+core_initcall(hook_pci_bus);