[Qemu-devel] [PATCH V3] hw/virtio: Add PCIe capability to virtio devices

[Marcel Apfelbaum <marcel@redhat.com>]

The virtio devices are converted to PCI-Express
if they are plugged into a PCI-Express bus and
the 'modern' protocol is enabled.

Devices plugged directly into the Root Complex as
Integrated Endpoints remain PCI.

Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
---
v2 -> v3:
 - Addressed Michael S. Tsirkin's comments:
   - enable pcie only for 2.5+ machines.

v1 -> v2:
 - Addressed Michael S. Tsirkin's comments:
   - Added the minimum required capabilities for PCIe devices
   - Integrated Endpoints remain PCI

 - Use pcie_endpoint_cap_init instead of manually creating the pcie capability.

 - Regarding Gerd Hoffman's comments:
   - Creating virtio-pcie devices:
     For the moment I prefer to not duplicate the virtio definitions,
     at least until we don't have a consensus (Personally I don't like it)
   - Removing the IO bar:
     This would be my next patch on the "virtio to express" series, I plan
     to remove it only for "modern" devices.

Thanks,
Marcel

 hw/virtio/virtio-pci.c | 22 ++++++++++++++++++++++
 hw/virtio/virtio-pci.h |  2 ++
 include/hw/compat.h    | 46 +++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index f55dd2b..a288d8b 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1592,6 +1592,26 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error **errp)
 
     address_space_init(&proxy->modern_as, &proxy->modern_cfg, "virtio-pci-cfg-as");
 
+    if (!(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_PCIE)
+        && !(proxy->flags & VIRTIO_PCI_FLAG_DISABLE_MODERN)
+        && pci_bus_is_express(pci_dev->bus)
+        && !pci_bus_is_root(pci_dev->bus)) {
+        int pos;
+
+        pci_dev->cap_present |= QEMU_PCI_CAP_EXPRESS;
+        pos = pcie_endpoint_cap_init(pci_dev, 0);
+        assert(pos > 0);
+
+        pos = pci_add_capability(pci_dev, PCI_CAP_ID_PM, 0, PCI_PM_SIZEOF);
+        assert(pos > 0);
+
+        /*
+         * Indicates that this function complies with revision 1.2 of the
+         * PCI Power Management Interface Specification.
+         */
+        pci_set_word(pci_dev->config + pos + PCI_PM_PMC, 0x3);
+    }
+
     virtio_pci_bus_new(&proxy->bus, sizeof(proxy->bus), proxy);
     if (k->realize) {
         k->realize(proxy, errp);
@@ -1622,6 +1642,8 @@ static Property virtio_pci_properties[] = {
                     VIRTIO_PCI_FLAG_DISABLE_LEGACY_BIT, false),
     DEFINE_PROP_BIT("disable-modern", VirtIOPCIProxy, flags,
                     VIRTIO_PCI_FLAG_DISABLE_MODERN_BIT, true),
+    DEFINE_PROP_BIT("disable-pcie", VirtIOPCIProxy, flags,
+                    VIRTIO_PCI_FLAG_DISABLE_PCIE_BIT, false),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
index 801c23a..1a487fc 100644
--- a/hw/virtio/virtio-pci.h
+++ b/hw/virtio/virtio-pci.h
@@ -72,8 +72,10 @@ typedef struct VirtioBusClass VirtioPCIBusClass;
 /* virtio version flags */
 #define VIRTIO_PCI_FLAG_DISABLE_LEGACY_BIT 2
 #define VIRTIO_PCI_FLAG_DISABLE_MODERN_BIT 3
+#define VIRTIO_PCI_FLAG_DISABLE_PCIE_BIT 4
 #define VIRTIO_PCI_FLAG_DISABLE_LEGACY (1 << VIRTIO_PCI_FLAG_DISABLE_LEGACY_BIT)
 #define VIRTIO_PCI_FLAG_DISABLE_MODERN (1 << VIRTIO_PCI_FLAG_DISABLE_MODERN_BIT)
+#define VIRTIO_PCI_FLAG_DISABLE_PCIE (1 << VIRTIO_PCI_FLAG_DISABLE_PCIE_BIT)
 
 typedef struct {
     MSIMessage msg;
diff --git a/include/hw/compat.h b/include/hw/compat.h
index 095de5d..0a08531 100644
--- a/include/hw/compat.h
+++ b/include/hw/compat.h
@@ -2,7 +2,51 @@
 #define HW_COMPAT_H
 
 #define HW_COMPAT_2_4 \
-        /* empty */
+        {\
+            .driver   = "virtio-blk-pci",\
+            .property = "disable-pcie",\
+            .value    = "on",\
+        },{\
+            .driver   = "virtio-scsi-pci",\
+            .property = "disable-pcie",\
+            .value    = "on",\
+        },{\
+            .driver   = "virtio-net-pci",\
+            .property = "disable-pcie",\
+            .value    = "on",\
+        },{\
+            .driver   = "virtio-input-host-pci",\
+            .property = "disable-pcie",\
+            .value    = "on",\
+        },{\
+            .driver   = "virtio-keyboard-pci",\
+            .property = "disable-pcie",\
+            .value    = "on",\
+        },{\
+            .driver   = "virtio-mouse-pci",\
+            .property = "disable-pcie",\
+            .value    = "on",\
+        },{\
+            .driver   = "virtio-serial-pci",\
+            .property = "disable-pcie",\
+            .value    = "on",\
+        },{\
+            .driver   = "virtio-tablet-pci",\
+            .property = "disable-pcie",\
+            .value    = "on",\
+        },{\
+            .driver   = "virtio-gpu-pci",\
+            .property = "disable-pcie",\
+            .value    = "on",\
+        },{\
+            .driver   = "virtio-balloon-pci",\
+            .property = "disable-pcie",\
+            .value    = "on",\
+        },{\
+            .driver   = "virtio-rng-pci",\
+            .property = "disable-pcie",\
+            .value    = "on",\
+        },
 
 #define HW_COMPAT_2_3 \
         {\
-- 
2.1.0