Rectify length of Virtio descriptor address

According to Virtio Specification Version 1.3, Section 2.7.5 *The
Virtqueue Descriptor Table*, the type of 'addr' should be 'uint64_t'
instead of 'uint32_t'.
This commit addresses the error in the previous implementation.

Co-authored-by: Shengwen Cheng <[email protected]>

Author: otteryc

virtio-blk.c

@@ -102,7 +102,7 @@ static void virtio_blk_update_status(virtio_blk_state_t *vblk, uint32_t status)
 
 static void virtio_blk_write_handler(virtio_blk_state_t *vblk,
                                      uint64_t sector,
-                                     uint32_t desc_addr,
+                                     uint64_t desc_addr,
                                      uint32_t len)
 {
     void *dest = (void *) ((uintptr_t) vblk->disk + sector * DISK_BLK_SIZE);
@@ -112,7 +112,7 @@ static void virtio_blk_write_handler(virtio_blk_state_t *vblk,
 
 static void virtio_blk_read_handler(virtio_blk_state_t *vblk,
                                     uint64_t sector,
-                                    uint32_t desc_addr,
+                                    uint64_t desc_addr,
                                     uint32_t len)
 {
     void *dest = (void *) ((uintptr_t) vblk->ram + desc_addr);
@@ -141,13 +141,15 @@ static int virtio_blk_desc_handler(virtio_blk_state_t *vblk,
     /* Collect the descriptors */
     for (int i = 0; i < 3; i++) {
         /* The size of the `struct virtq_desc` is 4 words */
-        const uint32_t *desc = &vblk->ram[queue->QueueDesc + desc_idx * 4];
+        const struct virtq_desc *desc =
+            (struct virtq_desc *) &vblk->ram[queue->QueueDesc + desc_idx * 4];
+
 
         /* Retrieve the fields of current descriptor */
-        vq_desc[i].addr = desc[0];
-        vq_desc[i].len = desc[2];
-        vq_desc[i].flags = desc[3];
-        desc_idx = desc[3] >> 16; /* vq_desc[desc_cnt].next */
+        vq_desc[i].addr = desc->addr;
+        vq_desc[i].len = desc->len;
+        vq_desc[i].flags = desc->flags;
+        desc_idx = desc->next;
     }
 
     /* The next flag for the first and second descriptors should be set,

virtio-net.c

@@ -180,35 +180,36 @@ static ssize_t handle_write(netdev_t *netdev,
 /* Require existing 'desc_idx' to use as iteration variable, and input
  * 'buffer_idx'.
  */
-#define VNET_ITERATE_BUFFER(checked, body)                            \
-    desc_idx = buffer_idx;                                            \
-    while (1) {                                                       \
-        if (checked && desc_idx >= queue->QueueNum)                   \
-            return virtio_net_set_fail(vnet);                         \
-        const uint32_t *desc = &ram[queue->QueueDesc + desc_idx * 4]; \
-        uint16_t desc_flags = desc[3];                                \
-        body if (!(desc_flags & VIRTIO_DESC_F_NEXT)) break;           \
-        desc_idx = desc[3] >> 16;                                     \
+#define VNET_ITERATE_BUFFER(checked, body)                               \
+    desc_idx = buffer_idx;                                               \
+    while (1) {                                                          \
+        if (checked && desc_idx >= queue->QueueNum)                      \
+            return virtio_net_set_fail(vnet);                            \
+        const struct virtq_desc *desc =                                  \
+            (struct virtq_desc *) &ram[queue->QueueDesc + desc_idx * 4]; \
+        uint16_t desc_flags = desc->flags;                               \
+        body if (!(desc_flags & VIRTIO_DESC_F_NEXT)) break;              \
+        desc_idx = desc->next;                                           \
     }
 
 /* Input: 'buffer_idx'.
  * Output: 'buffer_niovs' and 'buffer_iovs'
  */
-#define VNET_BUFFER_TO_IOV(expect_readable)                               \
-    uint16_t desc_idx;                                                    \
-    /* do a first pass to validate flags and count buffers */             \
-    size_t buffer_niovs = 0;                                              \
-    VNET_ITERATE_BUFFER(                                                  \
-        true, if ((!!(desc_flags & VIRTIO_DESC_F_WRITE)) !=               \
-                  (expect_readable)) return virtio_net_set_fail(vnet);    \
-        buffer_niovs++;)                                                  \
-    /* convert to iov */                                                  \
-    struct iovec buffer_iovs[buffer_niovs];                               \
-    buffer_niovs = 0;                                                     \
-    VNET_ITERATE_BUFFER(                                                  \
-        false, uint32_t desc_addr = desc[0]; uint32_t desc_len = desc[2]; \
-        buffer_iovs[buffer_niovs].iov_base =                              \
-            (void *) ((uintptr_t) ram + desc_addr);                       \
+#define VNET_BUFFER_TO_IOV(expect_readable)                                    \
+    uint16_t desc_idx;                                                         \
+    /* do a first pass to validate flags and count buffers */                  \
+    size_t buffer_niovs = 0;                                                   \
+    VNET_ITERATE_BUFFER(                                                       \
+        true, if ((!!(desc_flags & VIRTIO_DESC_F_WRITE)) !=                    \
+                  (expect_readable)) return virtio_net_set_fail(vnet);         \
+        buffer_niovs++;)                                                       \
+    /* convert to iov */                                                       \
+    struct iovec buffer_iovs[buffer_niovs];                                    \
+    buffer_niovs = 0;                                                          \
+    VNET_ITERATE_BUFFER(                                                       \
+        false, uint64_t desc_addr = desc->addr; uint32_t desc_len = desc->len; \
+        buffer_iovs[buffer_niovs].iov_base =                                   \
+            (void *) ((uintptr_t) ram + desc_addr);                            \
         buffer_iovs[buffer_niovs].iov_len = desc_len; buffer_niovs++;)
 
 #define VNET_GENERATE_QUEUE_HANDLER(NAME_SUFFIX, VERB, QUEUE_IDX, READ)        \

virtio-rng.c

@@ -61,20 +61,16 @@ static void virtio_queue_notify_handler(virtio_rng_state_t *vrng,
     VRNG_QUEUE.last_avail++;
 
     /* Read descriptor */
-    uint32_t *desc = &vrng->ram[queue->QueueDesc + buffer_idx * 4];
-    struct virtq_desc vq_desc = {
-        .addr = desc[0],
-        .len = desc[2],
-        .flags = desc[3],
-    };
+    struct virtq_desc *vq_desc =
+        (struct virtq_desc *) &vrng->ram[queue->QueueDesc + buffer_idx * 4];
 
     /* Write entropy buffer */
     void *entropy_buf =
-        (void *) ((uintptr_t) vrng->ram + (uintptr_t) vq_desc.addr);
-    ssize_t total = read(rng_fd, entropy_buf, vq_desc.len);
+        (void *) ((uintptr_t) vrng->ram + (uintptr_t) vq_desc->addr);
+    ssize_t total = read(rng_fd, entropy_buf, vq_desc->len);
 
     /* Clear write flag */
-    desc[3] = 0;
+    vq_desc->flags = 0;
 
     /* Get virtq_used.idx (le16) */
     uint16_t used = ram[queue->QueueUsed] >> 16;

virtio.h

@@ -57,9 +57,9 @@ enum {
 #undef _
 };
 
-struct virtq_desc {
-    uint32_t addr;
+PACKED(struct virtq_desc {
+    uint64_t addr;
     uint32_t len;
     uint16_t flags;
     uint16_t next;
-};
+});