vdpa_sim: move buffer allocation in the devices

Currently, the vdpa_sim core does not use the buffer, but only
allocates it.

The buffer is used by devices differently, and some future devices
may not use it. So let's move all its management inside the devices.

Add a new `free` device callback called to clean up the resources
allocated by the device.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20230407133658.66339-2-sgarzare@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 21 insertions, 7 deletions

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
index 55920502f76b..cfe962911804 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
@@ -58,6 +58,7 @@ struct vdpasim_net{
 	struct vdpasim_dataq_stats tx_stats;
 	struct vdpasim_dataq_stats rx_stats;
 	struct vdpasim_cq_stats cq_stats;
+	void *buffer;
 };
 
 static struct vdpasim_net *sim_to_net(struct vdpasim *vdpasim)
@@ -87,14 +88,15 @@ static bool receive_filter(struct vdpasim *vdpasim, size_t len)
 	size_t hdr_len = modern ? sizeof(struct virtio_net_hdr_v1) :
 				  sizeof(struct virtio_net_hdr);
 	struct virtio_net_config *vio_config = vdpasim->config;
+	struct vdpasim_net *net = sim_to_net(vdpasim);
 
 	if (len < ETH_ALEN + hdr_len)
 		return false;
 
-	if (is_broadcast_ether_addr(vdpasim->buffer + hdr_len) ||
-	    is_multicast_ether_addr(vdpasim->buffer + hdr_len))
+	if (is_broadcast_ether_addr(net->buffer + hdr_len) ||
+	    is_multicast_ether_addr(net->buffer + hdr_len))
 		return true;
-	if (!strncmp(vdpasim->buffer + hdr_len, vio_config->mac, ETH_ALEN))
+	if (!strncmp(net->buffer + hdr_len, vio_config->mac, ETH_ALEN))
 		return true;
 
 	return false;
@@ -225,8 +227,7 @@ static void vdpasim_net_work(struct vdpasim *vdpasim)
 
 		++tx_pkts;
 		read = vringh_iov_pull_iotlb(&txq->vring, &txq->out_iov,
-					     vdpasim->buffer,
-					     PAGE_SIZE);
+					     net->buffer, PAGE_SIZE);
 
 		tx_bytes += read;
 
@@ -245,7 +246,7 @@ static void vdpasim_net_work(struct vdpasim *vdpasim)
 		}
 
 		write = vringh_iov_push_iotlb(&rxq->vring, &rxq->in_iov,
-					      vdpasim->buffer, read);
+					      net->buffer, read);
 		if (write <= 0) {
 			++rx_errors;
 			break;
@@ -427,6 +428,13 @@ static void vdpasim_net_setup_config(struct vdpasim *vdpasim,
 		vio_config->mtu = cpu_to_vdpasim16(vdpasim, 1500);
 }
 
+static void vdpasim_net_free(struct vdpasim *vdpasim)
+{
+	struct vdpasim_net *net = sim_to_net(vdpasim);
+
+	kvfree(net->buffer);
+}
+
 static void vdpasim_net_mgmtdev_release(struct device *dev)
 {
 }
@@ -456,7 +464,7 @@ static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
 	dev_attr.get_config = vdpasim_net_get_config;
 	dev_attr.work_fn = vdpasim_net_work;
 	dev_attr.get_stats = vdpasim_net_get_stats;
-	dev_attr.buffer_size = PAGE_SIZE;
+	dev_attr.free = vdpasim_net_free;
 
 	simdev = vdpasim_create(&dev_attr, config);
 	if (IS_ERR(simdev))
@@ -470,6 +478,12 @@ static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
 	u64_stats_init(&net->rx_stats.syncp);
 	u64_stats_init(&net->cq_stats.syncp);
 
+	net->buffer = kvmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!net->buffer) {
+		ret = -ENOMEM;
+		goto reg_err;
+	}
+
 	/*
 	 * Initialization must be completed before this call, since it can
 	 * connect the device to the vDPA bus, so requests can arrive after