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vdpa: move file descriptor to vhost_vdpa_shared 
Next patches will register the vhost_vdpa memory listener while the VM
is migrating at the destination, so we can map the memory to the device
before stopping the VM at the source.  The main goal is to reduce the
downtime.

However, the destination QEMU is unaware of which vhost_vdpa device will
register its memory_listener.  If the source guest has CVQ enabled, it
will be the CVQ device.  Otherwise, it  will be the first one.

Move the file descriptor to VhostVDPAShared so all vhost_vdpa can use
it, rather than always in the first / last vhost_vdpa.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20231221174322.3130442-7-eperezma@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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@eugpermar @mstsirkin
eugpermar authored and mstsirkin committed Dec 26, 2023
1 parent e36b999 commit f12b249
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Showing 4 changed files with 13 additions and 16 deletions.
2 changes: 1 addition & 1 deletion hw/virtio/vdpa-dev.c
View file
Expand Up @@ -66,7 +66,6 @@ static void vhost_vdpa_device_realize(DeviceState *dev, Error **errp)
if (*errp) {
return;
}
v->vdpa.device_fd = v->vhostfd;

v->vdev_id = vhost_vdpa_device_get_u32(v->vhostfd,
VHOST_VDPA_GET_DEVICE_ID, errp);
Expand Down Expand Up @@ -115,6 +114,7 @@ static void vhost_vdpa_device_realize(DeviceState *dev, Error **errp)
goto free_vqs;
}
v->vdpa.shared = g_new0(VhostVDPAShared, 1);
v->vdpa.shared->device_fd = v->vhostfd;
v->vdpa.shared->iova_range = iova_range;

ret = vhost_dev_init(&v->dev, &v->vdpa, VHOST_BACKEND_TYPE_VDPA, 0, NULL);
Expand Down
14 changes: 7 additions & 7 deletions hw/virtio/vhost-vdpa.c
View file
Expand Up @@ -90,7 +90,7 @@ int vhost_vdpa_dma_map(struct vhost_vdpa *v, uint32_t asid, hwaddr iova,
hwaddr size, void *vaddr, bool readonly)
{
struct vhost_msg_v2 msg = {};
int fd = v->device_fd;
int fd = v->shared->device_fd;
int ret = 0;

msg.type = v->msg_type;
Expand Down Expand Up @@ -122,7 +122,7 @@ int vhost_vdpa_dma_unmap(struct vhost_vdpa *v, uint32_t asid, hwaddr iova,
hwaddr size)
{
struct vhost_msg_v2 msg = {};
int fd = v->device_fd;
int fd = v->shared->device_fd;
int ret = 0;

msg.type = v->msg_type;
Expand All @@ -145,7 +145,7 @@ int vhost_vdpa_dma_unmap(struct vhost_vdpa *v, uint32_t asid, hwaddr iova,

static void vhost_vdpa_listener_begin_batch(struct vhost_vdpa *v)
{
int fd = v->device_fd;
int fd = v->shared->device_fd;
struct vhost_msg_v2 msg = {
.type = v->msg_type,
.iotlb.type = VHOST_IOTLB_BATCH_BEGIN,
Expand Down Expand Up @@ -174,7 +174,7 @@ static void vhost_vdpa_listener_commit(MemoryListener *listener)
struct vhost_vdpa *v = container_of(listener, struct vhost_vdpa, listener);
struct vhost_dev *dev = v->dev;
struct vhost_msg_v2 msg = {};
int fd = v->device_fd;
int fd = v->shared->device_fd;

if (!(dev->backend_cap & (0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH))) {
return;
Expand Down Expand Up @@ -499,7 +499,7 @@ static int vhost_vdpa_call(struct vhost_dev *dev, unsigned long int request,
void *arg)
{
struct vhost_vdpa *v = dev->opaque;
int fd = v->device_fd;
int fd = v->shared->device_fd;
int ret;

assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_VDPA);
Expand Down Expand Up @@ -661,7 +661,7 @@ static int vhost_vdpa_host_notifier_init(struct vhost_dev *dev, int queue_index)
struct vhost_vdpa *v = dev->opaque;
VirtIODevice *vdev = dev->vdev;
VhostVDPAHostNotifier *n;
int fd = v->device_fd;
int fd = v->shared->device_fd;
void *addr;
char *name;

Expand Down Expand Up @@ -1290,7 +1290,7 @@ static void vhost_vdpa_suspend(struct vhost_dev *dev)

if (dev->backend_cap & BIT_ULL(VHOST_BACKEND_F_SUSPEND)) {
trace_vhost_vdpa_suspend(dev);
r = ioctl(v->device_fd, VHOST_VDPA_SUSPEND);
r = ioctl(v->shared->device_fd, VHOST_VDPA_SUSPEND);
if (unlikely(r)) {
error_report("Cannot suspend: %s(%d)", g_strerror(errno), errno);
} else {
Expand Down
2 changes: 1 addition & 1 deletion include/hw/virtio/vhost-vdpa.h
View file
Expand Up @@ -32,6 +32,7 @@ typedef struct VhostVDPAHostNotifier {

/* Info shared by all vhost_vdpa device models */
typedef struct vhost_vdpa_shared {
int device_fd;
struct vhost_vdpa_iova_range iova_range;

/* IOVA mapping used by the Shadow Virtqueue */
Expand All @@ -42,7 +43,6 @@ typedef struct vhost_vdpa_shared {
} VhostVDPAShared;

typedef struct vhost_vdpa {
int device_fd;
int index;
uint32_t msg_type;
bool iotlb_batch_begin_sent;
Expand Down
11 changes: 4 additions & 7 deletions net/vhost-vdpa.c
View file
Expand Up @@ -235,14 +235,11 @@ static void vhost_vdpa_cleanup(NetClientState *nc)
vhost_net_cleanup(s->vhost_net);
g_free(s->vhost_net);
s->vhost_net = NULL;
}
if (s->vhost_vdpa.device_fd >= 0) {
qemu_close(s->vhost_vdpa.device_fd);
s->vhost_vdpa.device_fd = -1;
}
if (s->vhost_vdpa.index != 0) {
return;
}
qemu_close(s->vhost_vdpa.shared->device_fd);
g_free(s->vhost_vdpa.shared);
}

Expand Down Expand Up @@ -448,7 +445,7 @@ static int vhost_vdpa_set_address_space_id(struct vhost_vdpa *v,
};
int r;

r = ioctl(v->device_fd, VHOST_VDPA_SET_GROUP_ASID, &asid);
r = ioctl(v->shared->device_fd, VHOST_VDPA_SET_GROUP_ASID, &asid);
if (unlikely(r < 0)) {
error_report("Can't set vq group %u asid %u, errno=%d (%s)",
asid.index, asid.num, errno, g_strerror(errno));
Expand Down Expand Up @@ -544,7 +541,7 @@ static int vhost_vdpa_net_cvq_start(NetClientState *nc)
return 0;
}

cvq_group = vhost_vdpa_get_vring_group(v->device_fd,
cvq_group = vhost_vdpa_get_vring_group(v->shared->device_fd,
v->dev->vq_index_end - 1,
&err);
if (unlikely(cvq_group < 0)) {
Expand Down Expand Up @@ -1671,7 +1668,6 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
qemu_set_info_str(nc, TYPE_VHOST_VDPA);
s = DO_UPCAST(VhostVDPAState, nc, nc);

s->vhost_vdpa.device_fd = vdpa_device_fd;
s->vhost_vdpa.index = queue_pair_index;
s->always_svq = svq;
s->migration_state.notify = NULL;
Expand All @@ -1680,6 +1676,7 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
vhost_vdpa_net_valid_svq_features(features,
&s->vhost_vdpa.migration_blocker);
s->vhost_vdpa.shared = g_new0(VhostVDPAShared, 1);
s->vhost_vdpa.shared->device_fd = vdpa_device_fd;
s->vhost_vdpa.shared->iova_range = iova_range;
s->vhost_vdpa.shared->shadow_data = svq;
} else if (!is_datapath) {
Expand Down

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