qemu: Pass the pci/e address for qemu bridge

Pass the slot address while attaching bridges. This is needed
to determine the pci/e address of devices that are attached
to the bridge.

Fixes #210

Signed-off-by: Archana Shinde <archana.m.shinde@intel.com>

virtcontainers/bridge.go

@@ -26,6 +26,9 @@ type Bridge struct {
 
 	//ID is used to identify the bridge in the hypervisor
 	ID string
+
+	// Addr is the PCI/e slot of the bridge
+	Addr int
 }
 
 // addDevice on success adds the device ID to the bridge and return the address

virtcontainers/bridge_test.go

@@ -16,7 +16,7 @@ func TestAddRemoveDevice(t *testing.T) {
 	assert := assert.New(t)
 
 	// create a bridge
-	bridges := []*Bridge{{make(map[uint32]string), pciBridge, "rgb123"}}
+	bridges := []*Bridge{{make(map[uint32]string), pciBridge, "rgb123", 5}}
 
 	// add device
 	devID := "abc123"

virtcontainers/qemu.go

@@ -353,6 +353,10 @@ func (q *qemu) createSandbox(sandboxConfig SandboxConfig) error {
 		},
 	}
 
+	// Add bridges before any other devices. This way we make sure that
+	// bridge gets the first available PCI address i.e bridgePCIStartAddr
+	devices = q.arch.appendBridges(devices, q.state.Bridges)
+
 	devices = q.arch.append9PVolumes(devices, sandboxConfig.Volumes)
 	devices = q.arch.appendConsole(devices, q.getSandboxConsole(sandboxConfig.ID))
 
@@ -363,11 +367,6 @@ func (q *qemu) createSandbox(sandboxConfig SandboxConfig) error {
 		}
 	}
 
-	devices = q.arch.appendBridges(devices, q.state.Bridges)
-	if err != nil {
-		return err
-	}
-
 	var ioThread *govmmQemu.IOThread
 	if q.config.BlockDeviceDriver == VirtioSCSI {
 		devices, ioThread = q.arch.appendSCSIController(devices, q.config.EnableIOThreads)

virtcontainers/qemu_amd64.go

@@ -8,6 +8,7 @@ package virtcontainers
 import (
 	"fmt"
 	"os"
+	"strconv"
 
 	govmmQemu "github.com/intel/govmm/qemu"
 )
@@ -204,6 +205,8 @@ func (q *qemuAmd64) appendBridges(devices []govmmQemu.Device, bridges []Bridge)
 			t = govmmQemu.PCIEBridge
 		}
 
+		b.Addr = bridgePCIStartAddr + idx
+
 		devices = append(devices,
 			govmmQemu.BridgeDevice{
 				Type: t,
@@ -212,6 +215,7 @@ func (q *qemuAmd64) appendBridges(devices []govmmQemu.Device, bridges []Bridge)
 				// Each bridge is required to be assigned a unique chassis id > 0
 				Chassis: (idx + 1),
 				SHPC:    true,
+				Addr:    strconv.FormatInt(int64(b.Addr), 10),
 			},
 		)
 	}

virtcontainers/qemu_amd64_test.go

@@ -146,6 +146,7 @@ func TestQemuAmd64AppendBridges(t *testing.T) {
 			ID:      bridges[0].ID,
 			Chassis: 1,
 			SHPC:    true,
+			Addr:    "2",
 		},
 	}
 
@@ -168,6 +169,7 @@ func TestQemuAmd64AppendBridges(t *testing.T) {
 			ID:      bridges[0].ID,
 			Chassis: 1,
 			SHPC:    true,
+			Addr:    "2",
 		},
 	}
 

virtcontainers/qemu_arch_base.go

@@ -9,6 +9,7 @@ import (
 	"encoding/hex"
 	"fmt"
 	"os"
+	"strconv"
 
 	govmmQemu "github.com/intel/govmm/qemu"
 )
@@ -100,6 +101,12 @@ const (
 	defaultMsize9p          = 8192
 )
 
+// This is the PCI start address assigned to the first bridge that
+// is added on the qemu command line. In case of x86_64, the first two PCI
+// addresses (0 and 1) are used by the platform while in case of ARM, address
+// 0 is reserved.
+const bridgePCIStartAddr = 2
+
 const (
 	// VirtioBlock means use virtio-blk for hotplugging drives
 	VirtioBlock = "virtio-blk"
@@ -321,6 +328,8 @@ func (q *qemuArchBase) appendBridges(devices []govmmQemu.Device, bridges []Bridg
 			t = govmmQemu.PCIEBridge
 		}
 
+		b.Addr = bridgePCIStartAddr + idx
+
 		devices = append(devices,
 			govmmQemu.BridgeDevice{
 				Type: t,
@@ -329,6 +338,7 @@ func (q *qemuArchBase) appendBridges(devices []govmmQemu.Device, bridges []Bridg
 				// Each bridge is required to be assigned a unique chassis id > 0
 				Chassis: (idx + 1),
 				SHPC:    true,
+				Addr:    strconv.FormatInt(int64(b.Addr), 10),
 			},
 		)
 	}

virtcontainers/qemu_arch_base_test.go

@@ -327,6 +327,7 @@ func TestQemuArchBaseAppendBridges(t *testing.T) {
 			ID:      bridges[0].ID,
 			Chassis: 1,
 			SHPC:    true,
+			Addr:    "2",
 		},
 	}