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hw/virtio-net.c: set config size using host features

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Currently, the config size for virtio devices is hard coded. When a new
feature is added that changes the config size, drivers that assume a static
config size will break. For purposes of backward compatibility, there needs
to be a way to inform drivers of the config size needed to accommodate the
set of features enabled.

aliguori: merged in
 - hw/virtio-net: use existing macros to implement endof
 - hw/virtio-net: fix config_size data type

Signed-off-by: Jesse Larrew <jlarrew@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Jesse Larrew 2013-02-05 17:47:16 -06:00 committed by Anthony Liguori
parent 1e89ad5b00
commit 14f9b664b3
1 changed files with 36 additions and 8 deletions
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44
hw/virtio-net.c
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@ -73,8 +73,31 @@ typedef struct VirtIONet
int multiqueue; int multiqueue;
uint16_t max_queues; uint16_t max_queues;
uint16_t curr_queues; uint16_t curr_queues;
size_t config_size;
} VirtIONet; } VirtIONet;
/*
* Calculate the number of bytes up to and including the given 'field' of
* 'container'.
*/
#define endof(container, field) \
(offsetof(container, field) + sizeof(((container *)0)->field))
typedef struct VirtIOFeature {
uint32_t flags;
size_t end;
} VirtIOFeature;
static VirtIOFeature feature_sizes[] = {
{.flags = 1 << VIRTIO_NET_F_MAC,
.end = endof(struct virtio_net_config, mac)},
{.flags = 1 << VIRTIO_NET_F_STATUS,
.end = endof(struct virtio_net_config, status)},
{.flags = 1 << VIRTIO_NET_F_MQ,
.end = endof(struct virtio_net_config, max_virtqueue_pairs)},
{}
};
static VirtIONetQueue *virtio_net_get_subqueue(NetClientState *nc) static VirtIONetQueue *virtio_net_get_subqueue(NetClientState *nc)
{ {
VirtIONet *n = qemu_get_nic_opaque(nc); VirtIONet *n = qemu_get_nic_opaque(nc);
@ -104,15 +127,15 @@ static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config)
stw_p(&netcfg.status, n->status); stw_p(&netcfg.status, n->status);
stw_p(&netcfg.max_virtqueue_pairs, n->max_queues); stw_p(&netcfg.max_virtqueue_pairs, n->max_queues);
memcpy(netcfg.mac, n->mac, ETH_ALEN); memcpy(netcfg.mac, n->mac, ETH_ALEN);
memcpy(config, &netcfg, sizeof(netcfg)); memcpy(config, &netcfg, n->config_size);
} }
static void virtio_net_set_config(VirtIODevice *vdev, const uint8_t *config) static void virtio_net_set_config(VirtIODevice *vdev, const uint8_t *config)
{ {
VirtIONet *n = to_virtio_net(vdev); VirtIONet *n = to_virtio_net(vdev);
struct virtio_net_config netcfg; struct virtio_net_config netcfg = {};
memcpy(&netcfg, config, sizeof(netcfg)); memcpy(&netcfg, config, n->config_size);
if (!(n->vdev.guest_features >> VIRTIO_NET_F_CTRL_MAC_ADDR & 1) && if (!(n->vdev.guest_features >> VIRTIO_NET_F_CTRL_MAC_ADDR & 1) &&
memcmp(netcfg.mac, n->mac, ETH_ALEN)) { memcmp(netcfg.mac, n->mac, ETH_ALEN)) {
@ -1279,16 +1302,21 @@ static void virtio_net_guest_notifier_mask(VirtIODevice *vdev, int idx,
} }
VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf, VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf,
virtio_net_conf *net, virtio_net_conf *net, uint32_t host_features)
uint32_t host_features)
{ {
VirtIONet *n; VirtIONet *n;
int i; int i, config_size = 0;
for (i = 0; feature_sizes[i].flags != 0; i++) {
if (host_features & feature_sizes[i].flags) {
config_size = MAX(feature_sizes[i].end, config_size);
}
}
n = (VirtIONet *)virtio_common_init("virtio-net", VIRTIO_ID_NET, n = (VirtIONet *)virtio_common_init("virtio-net", VIRTIO_ID_NET,
sizeof(struct virtio_net_config), config_size, sizeof(VirtIONet));
sizeof(VirtIONet));
n->config_size = config_size;
n->vdev.get_config = virtio_net_get_config; n->vdev.get_config = virtio_net_get_config;
n->vdev.set_config = virtio_net_set_config; n->vdev.set_config = virtio_net_set_config;
n->vdev.get_features = virtio_net_get_features; n->vdev.get_features = virtio_net_get_features;