arm-bsp/fvp-baser-aemv8r64: add support for virtio-9p

This patch adds a device tree entry and kernel configs to enable file
sharing between the host and the FVP using the virtio P9 device
component.

Issue-Id: SCM-2299
Signed-off-by: Hugo L'Hostis <hugo.lhostis@arm.com>
Change-Id: Icd757e3c6281e5e84985a3caac72e860a4aeee7f
Signed-off-by: Jon Mason <jon.mason@arm.com>

meta-arm-bsp/documentation/fvp-baser-aemv8r64.md

@@ -152,10 +152,28 @@ runfvp script:
 
  - Type ``ctrl+c`` and wait for kas process to finish.
 
+### File sharing between host and fvp
+It is possible to share a directory between the host machine and the fvp using
+the virtio P9 device component included in the kernel. To do so, create a
+directory to be mounted from the host machine:
+
+    mkdir /path/to/host-mount-dir
+
+Then, add the following parameter containing the path to the directory when
+launching the model:
+
+    --parameter 'bp.virtiop9device.root_path=/path/to/host-mount-dir'
+
+Once you are logged into the fvp, the host directory can be mounted in a
+directory on the model using the following command:
+
+    mount -t 9p -o trans=virtio,version=9p2000.L FM /path/to/fvp-mount-dir
+
 Devices supported in the kernel
 -------------------------------
 
 - serial
+- virtio 9p
 - virtio disk
 - virtio network
 - watchdog

meta-arm-bsp/recipes-kernel/linux/arm-platforms-kmeta/bsp/arm-platforms/fvp-baser-aemv8r64.scc

@@ -1,3 +1,4 @@
 kconf hardware arm64.cfg
 kconf hardware fvp-common-peripherals.cfg
 include cfg/virtio.scc
+include virtio-9p.scc

meta-arm-bsp/recipes-kernel/linux/arm-platforms-kmeta/bsp/arm-platforms/virtio-9p.cfg

@@ -0,0 +1,4 @@
+CONFIG_NET_9P=y
+CONFIG_NET_9P_VIRTIO=y
+CONFIG_9P_FS=y
+CONFIG_9P_FS_POSIX_ACL=y

meta-arm-bsp/recipes-kernel/linux/arm-platforms-kmeta/bsp/arm-platforms/virtio-9p.scc

@@ -0,0 +1 @@
+kconf non-hardware virtio-9p.cfg

meta-arm-bsp/recipes-kernel/linux/files/fvp-baser-aemv8r64/fvp-baser-aemv8r64.dts

@@ -163,6 +163,12 @@
                 interrupts = <0x0 42 0x4>;
         };
 
+        virtio-p9@9c140000{
+                compatible = "virtio,mmio";
+                reg = <0x0 0x9c140000 0x0 0x1000>;
+                interrupts = <0x0 43 0x4>;
+        };
+
         virtio-net@9c150000 {
                 compatible = "virtio,mmio";
                 reg = <0 0x9c150000 0 0x200>;