dev: Add a VirtIO block device model

1 files changed, 186 insertions, 0 deletions

diff --git a/src/dev/virtio/block.hh b/src/dev/virtio/block.hh
new file mode 100644
index 000000000..bef29580b
--- /dev/null
+++ b/src/dev/virtio/block.hh
@@ -0,0 +1,186 @@
+/*
+ * Copyright (c) 2014 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Andreas Sandberg
+ */
+
+#ifndef __DEV_VIRTIO_BLOCK_HH__
+#define __DEV_VIRTIO_BLOCK_HH__
+
+#include "dev/virtio/base.hh"
+#include "dev/disk_image.hh"
+#include "dev/terminal.hh"
+
+struct VirtIOBlockParams;
+
+/**
+ * VirtIO block device
+ *
+ * The block device uses the following queues:
+ *  -# Requests
+ *
+ * A guest issues a request by creating a descriptor chain that starts
+ * with a BlkRequest. Immediately after the BlkRequest follows the
+ * data for the request. The data buffer(s) are either input or output
+ * descriptors depending on the request type. The last byte in the
+ * descriptor chain should always be writable by the host and contains
+ * the request status code (OK/Error).
+ *
+ * The protocol supports asynchronous request completion by returning
+ * descriptor chains when they have been populated by the backing
+ * store. However, there is little point in doing so here.
+ *
+ * @see https://github.com/rustyrussell/virtio-spec
+ * @see http://docs.oasis-open.org/virtio/virtio/v1.0/virtio-v1.0.html
+ */
+class VirtIOBlock : public VirtIODeviceBase
+{
+  public:
+    typedef VirtIOBlockParams Params;
+    VirtIOBlock(Params *params);
+    virtual ~VirtIOBlock();
+
+    void readConfig(PacketPtr pkt, Addr cfgOffset);
+
+  protected:
+    static const DeviceId ID_BLOCK = 0x02;
+
+    /**
+     * Block device configuration structure
+     *
+     * @note This needs to be changed if the supported feature set
+     * changes!
+     */
+    struct Config {
+        uint64_t capacity;
+    } M5_ATTR_PACKED;
+    Config config;
+
+    /** @{
+     * @name Feature bits
+     */
+    static const FeatureBits F_SIZE_MAX = (1 << 1);
+    static const FeatureBits F_SEG_MAX = (1 << 2);
+    static const FeatureBits F_GEOMETRY = (1 << 4);
+    static const FeatureBits F_RO = (1 << 5);
+    static const FeatureBits F_BLK_SIZE = (1 << 6);
+    static const FeatureBits F_TOPOLOGY = (1 << 10);
+    /** @} */
+
+    /** @{
+     * @name VirtIO block requests
+     */
+    typedef uint32_t RequestType;
+    /** Read request */
+    static const RequestType T_IN = 0;
+    /** Write request */
+    static const RequestType T_OUT = 1;
+    /** Flush device buffers */
+    static const RequestType T_FLUSH = 4;
+    /** @} */
+
+    /** @{
+     * @name VirtIO block request status
+     */
+    typedef uint8_t Status;
+    /** Request succeeded */
+    static const Status S_OK = 0;
+    /** Request failed due to a device error */
+    static const Status S_IOERR = 1;
+    /** Request not supported */
+    static const Status S_UNSUPP = 2;
+    /** @} */
+
+    /** VirtIO block device request as sent by guest */
+    struct BlkRequest {
+        RequestType type;
+        uint32_t reserved;
+        uint64_t sector;
+    } M5_ATTR_PACKED;
+
+    /**
+     * Device read request.
+     *
+     * @param req Disk request from guest.
+     * @param desc_chain Request descriptor chain (from start of
+     *                   request)
+     * @param off_data Offset into the descriptor chain where data
+     *                 should be written.
+     * @param size Request data size.
+     */
+    Status read(const BlkRequest &req, VirtDescriptor *desc_chain,
+                size_t off_data, size_t size);
+    /**
+     * Device write request.
+     *
+     * @param req Disk request from guest.
+     * @param desc_chain Request descriptor chain (from start of
+     *                   request)
+     * @param off_data Offset into the descriptor chain where data
+     *                 should be read.
+     * @param size Request data size.
+     */
+    Status write(const BlkRequest &req, VirtDescriptor *desc_chain,
+                 size_t off_data, size_t size);
+
+  protected:
+    /**
+     * Virtqueue for disk requests.
+     */
+    class RequestQueue
+        : public VirtQueue
+    {
+      public:
+        RequestQueue(PortProxy &proxy, uint16_t size, VirtIOBlock &_parent)
+            : VirtQueue(proxy, size), parent(_parent) {}
+        virtual ~RequestQueue() {}
+
+        void onNotifyDescriptor(VirtDescriptor *desc);
+
+        std::string name() const { return parent.name() + ".qRequests"; }
+
+      protected:
+        VirtIOBlock &parent;
+    };
+
+    /** Device I/O request queue */
+    RequestQueue qRequests;
+
+    /** Image backing this device */
+    DiskImage &image;
+};
+
+#endif // __DEV_VIRTIO_BLOCK_HH__