pc-bios/s390-ccw: Add virtio-net driver code

The driver provides the recv() and send() functions which will
be required by SLOF's libnet code for receiving and sending
packets.

Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1499863793-18627-11-git-send-email-thuth@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

pc-bios/s390-ccw/netboot.mak

@@ -1,7 +1,7 @@
 
 SLOF_DIR := $(SRC_PATH)/roms/SLOF
 
-NETOBJS := start.o sclp.o virtio.o netmain.o libc.a
+NETOBJS := start.o sclp.o virtio.o virtio-net.o netmain.o libc.a
 
 LIBC_INC := -nostdinc -I$(SLOF_DIR)/lib/libc/include
 LIBNET_INC := -I$(SLOF_DIR)/lib/libnet

pc-bios/s390-ccw/virtio-net.c

@@ -0,0 +1,135 @@
+/*
+ * Virtio-net driver for the s390-ccw firmware
+ *
+ * Copyright 2017 Thomas Huth, Red Hat Inc.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <ethernet.h>
+#include "s390-ccw.h"
+#include "virtio.h"
+
+#ifndef DEBUG_VIRTIO_NET
+#define DEBUG_VIRTIO_NET 0
+#endif
+
+#define VIRTIO_NET_F_MAC_BIT  (1 << 5)
+
+#define VQ_RX 0         /* Receive queue */
+#define VQ_TX 1         /* Transmit queue */
+
+struct VirtioNetHdr {
+    uint8_t flags;
+    uint8_t gso_type;
+    uint16_t hdr_len;
+    uint16_t gso_size;
+    uint16_t csum_start;
+    uint16_t csum_offset;
+    /*uint16_t num_buffers;*/ /* Only with VIRTIO_NET_F_MRG_RXBUF or VIRTIO1 */
+};
+typedef struct VirtioNetHdr VirtioNetHdr;
+
+static uint16_t rx_last_idx;  /* Last index in receive queue "used" ring */
+
+int virtio_net_init(void *mac_addr)
+{
+    VDev *vdev = virtio_get_device();
+    VRing *rxvq = &vdev->vrings[VQ_RX];
+    void *buf;
+    int i;
+
+    vdev->guest_features[0] = VIRTIO_NET_F_MAC_BIT;
+    virtio_setup_ccw(vdev);
+
+    IPL_assert(vdev->guest_features[0] & VIRTIO_NET_F_MAC_BIT,
+               "virtio-net device does not support the MAC address feature");
+    memcpy(mac_addr, vdev->config.net.mac, ETH_ALEN);
+
+    for (i = 0; i < 64; i++) {
+        buf = malloc(ETH_MTU_SIZE + sizeof(VirtioNetHdr));
+        IPL_assert(buf != NULL, "Can not allocate memory for receive buffers");
+        vring_send_buf(rxvq, buf, ETH_MTU_SIZE + sizeof(VirtioNetHdr),
+                       VRING_DESC_F_WRITE);
+    }
+    vring_notify(rxvq);
+
+    return 0;
+}
+
+int send(int fd, const void *buf, int len, int flags)
+{
+    VirtioNetHdr tx_hdr;
+    VDev *vdev = virtio_get_device();
+    VRing *txvq = &vdev->vrings[VQ_TX];
+
+    /* Set up header - we do not use anything special, so simply clear it */
+    memset(&tx_hdr, 0, sizeof(tx_hdr));
+
+    vring_send_buf(txvq, &tx_hdr, sizeof(tx_hdr), VRING_DESC_F_NEXT);
+    vring_send_buf(txvq, (void *)buf, len, VRING_HIDDEN_IS_CHAIN);
+    while (!vr_poll(txvq)) {
+        yield();
+    }
+    if (drain_irqs(txvq->schid)) {
+        puts("send: drain irqs failed");
+        return -1;
+    }
+
+    return len;
+}
+
+int recv(int fd, void *buf, int maxlen, int flags)
+{
+    VDev *vdev = virtio_get_device();
+    VRing *rxvq = &vdev->vrings[VQ_RX];
+    int len, id;
+    uint8_t *pkt;
+
+    if (rx_last_idx == rxvq->used->idx) {
+        return 0;
+    }
+
+    len = rxvq->used->ring[rx_last_idx % rxvq->num].len - sizeof(VirtioNetHdr);
+    if (len > maxlen) {
+        puts("virtio-net: Receive buffer too small");
+        len = maxlen;
+    }
+    id = rxvq->used->ring[rx_last_idx % rxvq->num].id % rxvq->num;
+    pkt = (uint8_t *)(rxvq->desc[id].addr + sizeof(VirtioNetHdr));
+
+#if DEBUG_VIRTIO_NET   /* Dump packet */
+    int i;
+    printf("\nbuf %p: len=%i\n", (void *)rxvq->desc[id].addr, len);
+    for (i = 0; i < 64; i++) {
+        printf(" %02x", pkt[i]);
+        if ((i % 16) == 15) {
+            printf("\n");
+        }
+    }
+    printf("\n");
+#endif
+
+    /* Copy data to destination buffer */
+    memcpy(buf, pkt, len);
+
+    /* Mark buffer as available to the host again */
+    rxvq->avail->ring[rxvq->avail->idx % rxvq->num] = id;
+    rxvq->avail->idx = rxvq->avail->idx + 1;
+    vring_notify(rxvq);
+
+    /* Move index to next entry */
+    rx_last_idx = rx_last_idx + 1;
+
+    return len;
+}

pc-bios/s390-ccw/virtio.c

@@ -266,6 +266,11 @@ void virtio_setup_ccw(VDev *vdev)
     run_ccw(vdev, CCW_CMD_VDEV_RESET, NULL, 0);
 
     switch (vdev->senseid.cu_model) {
+    case VIRTIO_ID_NET:
+        vdev->nr_vqs = 2;
+        vdev->cmd_vr_idx = 0;
+        cfg_size = sizeof(vdev->config.net);
+        break;
     case VIRTIO_ID_BLOCK:
         vdev->nr_vqs = 1;
         vdev->cmd_vr_idx = 0;

pc-bios/s390-ccw/virtio.h

@@ -11,8 +11,6 @@
 #ifndef VIRTIO_H
 #define VIRTIO_H
 
-#include "s390-ccw.h"
-
 /* Status byte for guest to report progress, and synchronize features. */
 /* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */
 #define VIRTIO_CONFIG_S_ACKNOWLEDGE     1
@@ -227,6 +225,13 @@ struct ScsiDevice {
 };
 typedef struct ScsiDevice ScsiDevice;
 
+struct VirtioNetConfig {
+    uint8_t mac[6];
+    /* uint16_t status; */               /* Only with VIRTIO_NET_F_STATUS */
+    /* uint16_t max_virtqueue_pairs; */  /* Only with VIRTIO_NET_F_MQ */
+};
+typedef struct VirtioNetConfig VirtioNetConfig;
+
 struct VDev {
     int nr_vqs;
     VRing *vrings;
@@ -239,6 +244,7 @@ struct VDev {
     union {
         VirtioBlkConfig blk;
         VirtioScsiConfig scsi;
+        VirtioNetConfig net;
     } config;
     ScsiDevice *scsi_device;
     bool is_cdrom;
@@ -273,4 +279,6 @@ int vring_wait_reply(void);
 int virtio_run(VDev *vdev, int vqid, VirtioCmd *cmd);
 void virtio_setup_ccw(VDev *vdev);
 
+int virtio_net_init(void *mac_addr);
+
 #endif /* VIRTIO_H */