adding docs/commands.md

Author: MalteJ

docs/commands.md

@@ -0,0 +1,20 @@
+As kernstore will primarily serve block devices for VMs, which access their storage via virtio-blk, we only need to implement functionality serving the following virtio-blk commands:
+
+
+    /* Read from volume */
+    #define VIRTIO_BLK_T_IN 0
+  
+    /* Write to volume */
+    #define VIRTIO_BLK_T_OUT 1
+    
+    /* Cache flush command */
+    #define VIRTIO_BLK_T_FLUSH 4
+    
+    /* Get device ID command */
+    #define VIRTIO_BLK_T_GET_ID 8
+    
+    /* Discard command */
+    #define VIRTIO_BLK_T_DISCARD 11
+    
+    /* Write zeroes command */
+    #define VIRTIO_BLK_T_WRITE_ZEROES 13