virtio: Provide version-specific variants of virtio PCI devices

Many of the current virtio-*-pci device types actually represent
3 different types of devices:
* virtio 1.0 non-transitional devices
* virtio 1.0 transitional devices
* virtio 0.9 ("legacy device" in virtio 1.0 terminology)

That would be just an annoyance if it didn't break our device/bus
compatibility QMP interfaces.  With these multi-purpose device
types, there's no way to tell management software that
transitional devices and legacy devices require a Conventional
PCI bus.

The multi-purpose device types would also prevent us from telling
management software what's the PCI vendor/device ID for them,
because their PCI IDs change at runtime depending on the bus
where they were plugged.

This patch adds separate device types for each of those virtio
device flavors:

- virtio-*-pci: the existing multi-purpose device types
  - Configurable using `disable-legacy` and `disable-modern`
    properties
  - Legacy driver support is automatically enabled/disabled
    depending on the bus where it is plugged
  - Supports Conventional PCI and PCI Express buses
    (but Conventional PCI is incompatible with
    disable-legacy=off)
  - Changes PCI vendor/device IDs at runtime
- virtio-*-pci-transitional: virtio-1.0 device supporting legacy drivers
  - Supports Conventional PCI buses only, because
    it has a PIO BAR
- virtio-*-pci-non-transitional: modern-only
  - Supports both Conventional PCI and PCI Express buses

The existing TYPE_* macros for these types will point to an
abstract base type, so existing casts in the code will keep
working for all variants.

A simple test script (tests/acceptance/virtio_version.py) is
included, to check if the new device types are equivalent to
using the `disable-legacy` and `disable-modern` options.

Acked-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 176 insertions, 0 deletions

diff --git a/tests/acceptance/virtio_version.py b/tests/acceptance/virtio_version.py
new file mode 100644
index 0000000000..ce990250d8
--- /dev/null
+++ b/tests/acceptance/virtio_version.py
@@ -0,0 +1,176 @@
+"""
+Check compatibility of virtio device types
+"""
+# Copyright (c) 2018 Red Hat, Inc.
+#
+# Author:
+#  Eduardo Habkost <ehabkost@redhat.com>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or
+# later.  See the COPYING file in the top-level directory.
+import sys
+import os
+
+sys.path.append(os.path.join(os.path.dirname(__file__), "..", "..", "scripts"))
+from qemu import QEMUMachine
+from avocado_qemu import Test
+
+# Virtio Device IDs:
+VIRTIO_NET = 1
+VIRTIO_BLOCK = 2
+VIRTIO_CONSOLE = 3
+VIRTIO_RNG = 4
+VIRTIO_BALLOON = 5
+VIRTIO_RPMSG = 7
+VIRTIO_SCSI = 8
+VIRTIO_9P = 9
+VIRTIO_RPROC_SERIAL = 11
+VIRTIO_CAIF = 12
+VIRTIO_GPU = 16
+VIRTIO_INPUT = 18
+VIRTIO_VSOCK = 19
+VIRTIO_CRYPTO = 20
+
+PCI_VENDOR_ID_REDHAT_QUMRANET = 0x1af4
+
+# Device IDs for legacy/transitional devices:
+PCI_LEGACY_DEVICE_IDS = {
+    VIRTIO_NET:     0x1000,
+    VIRTIO_BLOCK:   0x1001,
+    VIRTIO_BALLOON: 0x1002,
+    VIRTIO_CONSOLE: 0x1003,
+    VIRTIO_SCSI:    0x1004,
+    VIRTIO_RNG:     0x1005,
+    VIRTIO_9P:      0x1009,
+    VIRTIO_VSOCK:   0x1012,
+}
+
+def pci_modern_device_id(virtio_devid):
+    return virtio_devid + 0x1040
+
+def devtype_implements(vm, devtype, implements):
+    return devtype in [d['name'] for d in vm.command('qom-list-types', implements=implements)]
+
+def get_pci_interfaces(vm, devtype):
+    interfaces = ('pci-express-device', 'conventional-pci-device')
+    return [i for i in interfaces if devtype_implements(vm, devtype, i)]
+
+class VirtioVersionCheck(Test):
+    """
+    Check if virtio-version-specific device types result in the
+    same device tree created by `disable-modern` and
+    `disable-legacy`.
+
+    :avocado: enable
+    :avocado: tags=x86_64
+    """
+
+    # just in case there are failures, show larger diff:
+    maxDiff = 4096
+
+    def run_device(self, devtype, opts=None, machine='pc'):
+        """
+        Run QEMU with `-device DEVTYPE`, return device info from `query-pci`
+        """
+        with QEMUMachine(self.qemu_bin) as vm:
+            vm.set_machine(machine)
+            if opts:
+                devtype += ',' + opts
+            vm.add_args('-device', '%s,id=devfortest' % (devtype))
+            vm.add_args('-S')
+            vm.launch()
+
+            pcibuses = vm.command('query-pci')
+            alldevs = [dev for bus in pcibuses for dev in bus['devices']]
+            devfortest = [dev for dev in alldevs
+                          if dev['qdev_id'] == 'devfortest']
+            return devfortest[0], get_pci_interfaces(vm, devtype)
+
+
+    def assert_devids(self, dev, devid, non_transitional=False):
+        self.assertEqual(dev['id']['vendor'], PCI_VENDOR_ID_REDHAT_QUMRANET)
+        self.assertEqual(dev['id']['device'], devid)
+        if non_transitional:
+            self.assertTrue(0x1040 <= dev['id']['device'] <= 0x107f)
+            self.assertGreaterEqual(dev['id']['subsystem'], 0x40)
+
+    def check_all_variants(self, qemu_devtype, virtio_devid):
+        """Check if a virtio device type and its variants behave as expected"""
+        # Force modern mode:
+        dev_modern, _ = self.run_device(qemu_devtype,
+                                       'disable-modern=off,disable-legacy=on')
+        self.assert_devids(dev_modern, pci_modern_device_id(virtio_devid),
+                           non_transitional=True)
+
+        # <prefix>-non-transitional device types should be 100% equivalent to
+        # <prefix>,disable-modern=off,disable-legacy=on
+        dev_1_0, nt_ifaces = self.run_device('%s-non-transitional' % (qemu_devtype))
+        self.assertEqual(dev_modern, dev_1_0)
+
+        # Force transitional mode:
+        dev_trans, _ = self.run_device(qemu_devtype,
+                                      'disable-modern=off,disable-legacy=off')
+        self.assert_devids(dev_trans, PCI_LEGACY_DEVICE_IDS[virtio_devid])
+
+        # Force legacy mode:
+        dev_legacy, _ = self.run_device(qemu_devtype,
+                                       'disable-modern=on,disable-legacy=off')
+        self.assert_devids(dev_legacy, PCI_LEGACY_DEVICE_IDS[virtio_devid])
+
+        # No options: default to transitional on PC machine-type:
+        no_opts_pc, generic_ifaces = self.run_device(qemu_devtype)
+        self.assertEqual(dev_trans, no_opts_pc)
+
+        #TODO: check if plugging on a PCI Express bus will make the
+        #      device non-transitional
+        #no_opts_q35 = self.run_device(qemu_devtype, machine='q35')
+        #self.assertEqual(dev_modern, no_opts_q35)
+
+        # <prefix>-transitional device types should be 100% equivalent to
+        # <prefix>,disable-modern=off,disable-legacy=off
+        dev_trans, trans_ifaces = self.run_device('%s-transitional' % (qemu_devtype))
+        self.assertEqual(dev_trans, dev_trans)
+
+        # ensure the interface information is correct:
+        self.assertIn('conventional-pci-device', generic_ifaces)
+        self.assertIn('pci-express-device', generic_ifaces)
+
+        self.assertIn('conventional-pci-device', nt_ifaces)
+        self.assertIn('pci-express-device', nt_ifaces)
+
+        self.assertIn('conventional-pci-device', trans_ifaces)
+        self.assertNotIn('pci-express-device', trans_ifaces)
+
+
+    def test_conventional_devs(self):
+        self.check_all_variants('virtio-net-pci', VIRTIO_NET)
+        # virtio-blk requires 'driver' parameter
+        #self.check_all_variants('virtio-blk-pci', VIRTIO_BLOCK)
+        self.check_all_variants('virtio-serial-pci', VIRTIO_CONSOLE)
+        self.check_all_variants('virtio-rng-pci', VIRTIO_RNG)
+        self.check_all_variants('virtio-balloon-pci', VIRTIO_BALLOON)
+        self.check_all_variants('virtio-scsi-pci', VIRTIO_SCSI)
+        # virtio-9p requires 'fsdev' parameter
+        #self.check_all_variants('virtio-9p-pci', VIRTIO_9P)
+
+    def check_modern_only(self, qemu_devtype, virtio_devid):
+        """Check if a modern-only virtio device type behaves as expected"""
+        # Force modern mode:
+        dev_modern, _ = self.run_device(qemu_devtype,
+                                       'disable-modern=off,disable-legacy=on')
+        self.assert_devids(dev_modern, pci_modern_device_id(virtio_devid),
+                           non_transitional=True)
+
+        # No options: should be modern anyway
+        dev_no_opts, ifaces = self.run_device(qemu_devtype)
+        self.assertEqual(dev_modern, dev_no_opts)
+
+        self.assertIn('conventional-pci-device', ifaces)
+        self.assertIn('pci-express-device', ifaces)
+
+    def test_modern_only_devs(self):
+        self.check_modern_only('virtio-vga', VIRTIO_GPU)
+        self.check_modern_only('virtio-gpu-pci', VIRTIO_GPU)
+        self.check_modern_only('virtio-mouse-pci', VIRTIO_INPUT)
+        self.check_modern_only('virtio-tablet-pci', VIRTIO_INPUT)
+        self.check_modern_only('virtio-keyboard-pci', VIRTIO_INPUT)