Add a few instructions for testing the devices. Testing devices like vhost-scsi or vsock may seem daunting but is relatively easy. Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx> --- Documentation/io-testing.txt | 141 +++++++++++++++++++++++++++++++++++ 1 file changed, 141 insertions(+) create mode 100644 Documentation/io-testing.txt diff --git a/Documentation/io-testing.txt b/Documentation/io-testing.txt new file mode 100644 index 00000000..c2e41902 --- /dev/null +++ b/Documentation/io-testing.txt @@ -0,0 +1,141 @@ +This document describes how to test each device, which is required when +modifying the common I/O infrastructure. + + +9P +-- + + CONFIG_NET_9P_VIRTIO + +Without a --disk parameter, kvmtool shares part of the host filesystem +with the guest using 9p. Otherwise, use the `--9p <directory>,<tag>` +parameter to share a directory with the guest, and mount it in the guest +with: + + $ mount -t 9p <tag> <mountpoint> + + +BALLOON +------- + + CONFIG_VIRTIO_BALLOON + + $ lkvm run ... --balloon + +Display memory statistics: + + $ lkvm stat -a -m + *** Guest memory statistics *** + ... + +Remove 20MB of memory from the guest: + + $ lkvm balloon -n guest-$(pidof lkvm) -i 20 + + +BLOCK +----- + + CONFIG_VIRTIO_BLK + + $ lkvm run ... --disk <raw or qcow2 image> + + +CONSOLE +------- + + $ lkvm run ... --console virtio + +See also virtio-console.txt + + +NET +--- + + CONFIG_VIRTIO_NET (guest) + CONFIG_VHOST_NET (host) + +By default kvmtool instantiates a user network device. In order to test +both tap and vhost, setup a tap interface on a local network. + +In the host: + + # ip tuntap add tap0 mode tap user $USER + # ip link set tap0 up + # ip link add br0 type bridge + # ip link set tap0 master br0 + # ip link set br0 up + # ip addr add 192.168.3.1/24 dev br0 + + $ lkvm run ... -n mode=tap,tapif=tap0,vhost=1 + +In the guest: + + # ip link set eth0 up + # ip addr add 192.168.3.12/24 dev eth0 + $ ping -c 1 192.168.3.1 + 64 bytes from 192.168.3.1: seq=0 ttl=64 time=0.303 ms + + +RNG +--- + + CONFIG_HW_RANDOM_VIRTIO + + $ lkvm run ... --rng + +In the guest: + + $ cat /sys/devices/virtual/misc/hw_random/rng_available + virtio_rng.0 + + +SCSI +---- + + CONFIG_SCSI_VIRTIO (guest) + CONFIG_TCM_FILEIO (host) + CONFIG_VHOST_SCSI (host) + +In the host, create a fileio backstore and a target: + + # targetcli (https://github.com/open-iscsi/targetcli-fb) + /> cd backstores/fileio + /backstores/fileio> create kvmtool_1 /srv/kvmtool_1 2M + Created fileio kvmtool_1 with size 2097152 + /backstores/fileio> cd /vhost + /vhost> create + Created target naa.500140571c9308aa. + Created TPG 1. + /vhost> cd naa.500140571c9308aa/tpg1/luns + /vhost/naa.50...8aa/tpg1/luns> create /backstores/fileio/kvmtool_1 + Created LUN 0. + + $ lkvm run ... --disk scsi:naa.500140571c9308aa + [ 0.479644] scsi host0: Virtio SCSI HBA + [ 0.483009] scsi 0:0:1:0: Direct-Access LIO-ORG kvmtool_1 4.0 PQ: 0 ANSI: 6 + + [ 1.242833] sd 0:0:1:0: [sda] 4096 512-byte logical blocks: (2.10 MB/2.00 MiB) + + +VSOCK +----- + + CONFIG_VSOCKETS + CONFIG_VIRTIO_VSOCKETS (guest) + CONFIG_VHOST_VSOCK (host) + +In the host, start a vsock server: + + $ socat - VSOCK-LISTEN:1234 + +We pick 12 as the guest ID. 0 and 1 are reserved, and the host has default +ID 2. + + $ lkvm run ... --vsock 12 + +In the guest, send a message to the host: + + $ echo Hello | socat - VSOCK-CONNECT:2:1234 + +The host server should display "Hello". -- 2.40.1
