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Diffstat (limited to 'src/dev/virtio/block.hh')
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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 ℑ +}; + +#endif // __DEV_VIRTIO_BLOCK_HH__ |