virtio: add features as qdev properties

Add feature bits as properties to virtio. This makes it possible to e.g. define
machine without indirect buffer support, which is required for 0.10
compatibility, or without hardware checksum support, which is required for 0.11
compatibility.  Since default values for optional features are now set by qdev,
get_features callback has been modified: it sets non-optional bits, and clears
bits not supported by host.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 17 insertions, 8 deletions

diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 4e1d5e1..6d0f9dd 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -16,6 +16,8 @@
 #include <inttypes.h>
 
 #include "virtio.h"
+#include "virtio-blk.h"
+#include "virtio-net.h"
 #include "pci.h"
 #include "sysemu.h"
 #include "msix.h"
@@ -92,6 +94,7 @@ typedef struct {
     uint32_t nvectors;
     DriveInfo *dinfo;
     NICConf nic;
+    uint32_t host_features;
 } VirtIOPCIProxy;
 
 /* virtio device */
@@ -175,7 +178,7 @@ static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 	/* Guest does not negotiate properly?  We have to assume nothing. */
 	if (val & (1 << VIRTIO_F_BAD_FEATURE)) {
 	    if (vdev->bad_features)
-		val = vdev->bad_features(vdev);
+		val = proxy->host_features & vdev->bad_features(vdev);
 	    else
 		val = 0;
 	}
@@ -235,8 +238,7 @@ static uint32_t virtio_ioport_read(VirtIOPCIProxy *proxy, uint32_t addr)
 
     switch (addr) {
     case VIRTIO_PCI_HOST_FEATURES:
-        ret = vdev->get_features(vdev);
-        ret |= vdev->binding->get_features(proxy);
+        ret = proxy->host_features;
         break;
     case VIRTIO_PCI_GUEST_FEATURES:
         ret = vdev->guest_features;
@@ -382,11 +384,8 @@ static void virtio_write_config(PCIDevice *pci_dev, uint32_t address,
 
 static unsigned virtio_pci_get_features(void *opaque)
 {
-    unsigned ret = 0;
-    ret |= (1 << VIRTIO_F_NOTIFY_ON_EMPTY);
-    ret |= (1 << VIRTIO_RING_F_INDIRECT_DESC);
-    ret |= (1 << VIRTIO_F_BAD_FEATURE);
-    return ret;
+    VirtIOPCIProxy *proxy = opaque;
+    return proxy->host_features;
 }
 
 static const VirtIOBindings virtio_pci_bindings = {
@@ -442,6 +441,9 @@ static void virtio_init_pci(VirtIOPCIProxy *proxy, VirtIODevice *vdev,
                            virtio_map);
 
     virtio_bind_device(vdev, &virtio_pci_bindings, proxy);
+    proxy->host_features |= 0x1 << VIRTIO_F_NOTIFY_ON_EMPTY;
+    proxy->host_features |= 0x1 << VIRTIO_F_BAD_FEATURE;
+    proxy->host_features = vdev->get_features(vdev, proxy->host_features);
 }
 
 static int virtio_blk_init_pci(PCIDevice *pci_dev)
@@ -553,6 +555,7 @@ static PCIDeviceInfo virtio_info[] = {
             DEFINE_PROP_HEX32("class", VirtIOPCIProxy, class_code, 0),
             DEFINE_PROP_DRIVE("drive", VirtIOPCIProxy, dinfo),
             DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
+            DEFINE_VIRTIO_BLK_FEATURES(VirtIOPCIProxy, host_features),
             DEFINE_PROP_END_OF_LIST(),
         },
         .qdev.reset = virtio_pci_reset,
@@ -564,6 +567,7 @@ static PCIDeviceInfo virtio_info[] = {
         .romfile    = "pxe-virtio.bin",
         .qdev.props = (Property[]) {
             DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 3),
+            DEFINE_VIRTIO_NET_FEATURES(VirtIOPCIProxy, host_features),
             DEFINE_NIC_PROPERTIES(VirtIOPCIProxy, nic),
             DEFINE_PROP_END_OF_LIST(),
         },
@@ -575,6 +579,7 @@ static PCIDeviceInfo virtio_info[] = {
         .exit      = virtio_exit_pci,
         .qdev.props = (Property[]) {
             DEFINE_PROP_HEX32("class", VirtIOPCIProxy, class_code, 0),
+            DEFINE_VIRTIO_COMMON_FEATURES(VirtIOPCIProxy, host_features),
             DEFINE_PROP_END_OF_LIST(),
         },
         .qdev.reset = virtio_pci_reset,
@@ -583,6 +588,10 @@ static PCIDeviceInfo virtio_info[] = {
         .qdev.size = sizeof(VirtIOPCIProxy),
         .init      = virtio_balloon_init_pci,
         .exit      = virtio_exit_pci,
+        .qdev.props = (Property[]) {
+            DEFINE_VIRTIO_COMMON_FEATURES(VirtIOPCIProxy, host_features),
+            DEFINE_PROP_END_OF_LIST(),
+        },
         .qdev.reset = virtio_pci_reset,
     },{
         /* end of list */