Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 311 insertions, 0 deletions

diff --git a/include/sysemu/dma.h b/include/sysemu/dma.h
new file mode 100644
index 000000000..3201e7901
--- /dev/null
+++ b/include/sysemu/dma.h
@@ -0,0 +1,311 @@
+/*
+ * DMA helper functions
+ *
+ * Copyright (c) 2009, 2020 Red Hat
+ *
+ * This work is licensed under the terms of the GNU General Public License
+ * (GNU GPL), version 2 or later.
+ */
+
+#ifndef DMA_H
+#define DMA_H
+
+#include "exec/memory.h"
+#include "exec/address-spaces.h"
+#include "block/block.h"
+#include "block/accounting.h"
+
+typedef struct ScatterGatherEntry ScatterGatherEntry;
+
+typedef enum {
+    DMA_DIRECTION_TO_DEVICE = 0,
+    DMA_DIRECTION_FROM_DEVICE = 1,
+} DMADirection;
+
+struct QEMUSGList {
+    ScatterGatherEntry *sg;
+    int nsg;
+    int nalloc;
+    size_t size;
+    DeviceState *dev;
+    AddressSpace *as;
+};
+
+#ifndef CONFIG_USER_ONLY
+
+/*
+ * When an IOMMU is present, bus addresses become distinct from
+ * CPU/memory physical addresses and may be a different size.  Because
+ * the IOVA size depends more on the bus than on the platform, we more
+ * or less have to treat these as 64-bit always to cover all (or at
+ * least most) cases.
+ */
+typedef uint64_t dma_addr_t;
+
+#define DMA_ADDR_BITS 64
+#define DMA_ADDR_FMT "%" PRIx64
+
+static inline void dma_barrier(AddressSpace *as, DMADirection dir)
+{
+    /*
+     * This is called before DMA read and write operations
+     * unless the _relaxed form is used and is responsible
+     * for providing some sane ordering of accesses vs
+     * concurrently running VCPUs.
+     *
+     * Users of map(), unmap() or lower level st/ld_*
+     * operations are responsible for providing their own
+     * ordering via barriers.
+     *
+     * This primitive implementation does a simple smp_mb()
+     * before each operation which provides pretty much full
+     * ordering.
+     *
+     * A smarter implementation can be devised if needed to
+     * use lighter barriers based on the direction of the
+     * transfer, the DMA context, etc...
+     */
+    smp_mb();
+}
+
+/* Checks that the given range of addresses is valid for DMA.  This is
+ * useful for certain cases, but usually you should just use
+ * dma_memory_{read,write}() and check for errors */
+static inline bool dma_memory_valid(AddressSpace *as,
+                                    dma_addr_t addr, dma_addr_t len,
+                                    DMADirection dir)
+{
+    return address_space_access_valid(as, addr, len,
+                                      dir == DMA_DIRECTION_FROM_DEVICE,
+                                      MEMTXATTRS_UNSPECIFIED);
+}
+
+static inline MemTxResult dma_memory_rw_relaxed(AddressSpace *as,
+                                                dma_addr_t addr,
+                                                void *buf, dma_addr_t len,
+                                                DMADirection dir)
+{
+    return address_space_rw(as, addr, MEMTXATTRS_UNSPECIFIED,
+                            buf, len, dir == DMA_DIRECTION_FROM_DEVICE);
+}
+
+static inline MemTxResult dma_memory_read_relaxed(AddressSpace *as,
+                                                  dma_addr_t addr,
+                                                  void *buf, dma_addr_t len)
+{
+    return dma_memory_rw_relaxed(as, addr, buf, len, DMA_DIRECTION_TO_DEVICE);
+}
+
+static inline MemTxResult dma_memory_write_relaxed(AddressSpace *as,
+                                                   dma_addr_t addr,
+                                                   const void *buf,
+                                                   dma_addr_t len)
+{
+    return dma_memory_rw_relaxed(as, addr, (void *)buf, len,
+                                 DMA_DIRECTION_FROM_DEVICE);
+}
+
+/**
+ * dma_memory_rw: Read from or write to an address space from DMA controller.
+ *
+ * Return a MemTxResult indicating whether the operation succeeded
+ * or failed (eg unassigned memory, device rejected the transaction,
+ * IOMMU fault).
+ *
+ * @as: #AddressSpace to be accessed
+ * @addr: address within that address space
+ * @buf: buffer with the data transferred
+ * @len: the number of bytes to read or write
+ * @dir: indicates the transfer direction
+ */
+static inline MemTxResult dma_memory_rw(AddressSpace *as, dma_addr_t addr,
+                                        void *buf, dma_addr_t len,
+                                        DMADirection dir)
+{
+    dma_barrier(as, dir);
+
+    return dma_memory_rw_relaxed(as, addr, buf, len, dir);
+}
+
+/**
+ * dma_memory_read: Read from an address space from DMA controller.
+ *
+ * Return a MemTxResult indicating whether the operation succeeded
+ * or failed (eg unassigned memory, device rejected the transaction,
+ * IOMMU fault).  Called within RCU critical section.
+ *
+ * @as: #AddressSpace to be accessed
+ * @addr: address within that address space
+ * @buf: buffer with the data transferred
+ * @len: length of the data transferred
+ */
+static inline MemTxResult dma_memory_read(AddressSpace *as, dma_addr_t addr,
+                                          void *buf, dma_addr_t len)
+{
+    return dma_memory_rw(as, addr, buf, len, DMA_DIRECTION_TO_DEVICE);
+}
+
+/**
+ * address_space_write: Write to address space from DMA controller.
+ *
+ * Return a MemTxResult indicating whether the operation succeeded
+ * or failed (eg unassigned memory, device rejected the transaction,
+ * IOMMU fault).
+ *
+ * @as: #AddressSpace to be accessed
+ * @addr: address within that address space
+ * @buf: buffer with the data transferred
+ * @len: the number of bytes to write
+ */
+static inline MemTxResult dma_memory_write(AddressSpace *as, dma_addr_t addr,
+                                           const void *buf, dma_addr_t len)
+{
+    return dma_memory_rw(as, addr, (void *)buf, len,
+                         DMA_DIRECTION_FROM_DEVICE);
+}
+
+/**
+ * dma_memory_set: Fill memory with a constant byte from DMA controller.
+ *
+ * Return a MemTxResult indicating whether the operation succeeded
+ * or failed (eg unassigned memory, device rejected the transaction,
+ * IOMMU fault).
+ *
+ * @as: #AddressSpace to be accessed
+ * @addr: address within that address space
+ * @c: constant byte to fill the memory
+ * @len: the number of bytes to fill with the constant byte
+ */
+MemTxResult dma_memory_set(AddressSpace *as, dma_addr_t addr,
+                           uint8_t c, dma_addr_t len);
+
+/**
+ * address_space_map: Map a physical memory region into a host virtual address.
+ *
+ * May map a subset of the requested range, given by and returned in @plen.
+ * May return %NULL and set *@plen to zero(0), if resources needed to perform
+ * the mapping are exhausted.
+ * Use only for reads OR writes - not for read-modify-write operations.
+ *
+ * @as: #AddressSpace to be accessed
+ * @addr: address within that address space
+ * @len: pointer to length of buffer; updated on return
+ * @dir: indicates the transfer direction
+ */
+static inline void *dma_memory_map(AddressSpace *as,
+                                   dma_addr_t addr, dma_addr_t *len,
+                                   DMADirection dir)
+{
+    hwaddr xlen = *len;
+    void *p;
+
+    p = address_space_map(as, addr, &xlen, dir == DMA_DIRECTION_FROM_DEVICE,
+                          MEMTXATTRS_UNSPECIFIED);
+    *len = xlen;
+    return p;
+}
+
+/**
+ * address_space_unmap: Unmaps a memory region previously mapped
+ *                      by dma_memory_map()
+ *
+ * Will also mark the memory as dirty if @dir == %DMA_DIRECTION_FROM_DEVICE.
+ * @access_len gives the amount of memory that was actually read or written
+ * by the caller.
+ *
+ * @as: #AddressSpace used
+ * @buffer: host pointer as returned by address_space_map()
+ * @len: buffer length as returned by address_space_map()
+ * @dir: indicates the transfer direction
+ * @access_len: amount of data actually transferred
+ */
+static inline void dma_memory_unmap(AddressSpace *as,
+                                    void *buffer, dma_addr_t len,
+                                    DMADirection dir, dma_addr_t access_len)
+{
+    address_space_unmap(as, buffer, (hwaddr)len,
+                        dir == DMA_DIRECTION_FROM_DEVICE, access_len);
+}
+
+#define DEFINE_LDST_DMA(_lname, _sname, _bits, _end) \
+    static inline uint##_bits##_t ld##_lname##_##_end##_dma(AddressSpace *as, \
+                                                            dma_addr_t addr) \
+    {                                                                   \
+        uint##_bits##_t val;                                            \
+        dma_memory_read(as, addr, &val, (_bits) / 8);                   \
+        return _end##_bits##_to_cpu(val);                               \
+    }                                                                   \
+    static inline void st##_sname##_##_end##_dma(AddressSpace *as,      \
+                                                 dma_addr_t addr,       \
+                                                 uint##_bits##_t val)   \
+    {                                                                   \
+        val = cpu_to_##_end##_bits(val);                                \
+        dma_memory_write(as, addr, &val, (_bits) / 8);                  \
+    }
+
+static inline uint8_t ldub_dma(AddressSpace *as, dma_addr_t addr)
+{
+    uint8_t val;
+
+    dma_memory_read(as, addr, &val, 1);
+    return val;
+}
+
+static inline void stb_dma(AddressSpace *as, dma_addr_t addr, uint8_t val)
+{
+    dma_memory_write(as, addr, &val, 1);
+}
+
+DEFINE_LDST_DMA(uw, w, 16, le);
+DEFINE_LDST_DMA(l, l, 32, le);
+DEFINE_LDST_DMA(q, q, 64, le);
+DEFINE_LDST_DMA(uw, w, 16, be);
+DEFINE_LDST_DMA(l, l, 32, be);
+DEFINE_LDST_DMA(q, q, 64, be);
+
+#undef DEFINE_LDST_DMA
+
+struct ScatterGatherEntry {
+    dma_addr_t base;
+    dma_addr_t len;
+};
+
+void qemu_sglist_init(QEMUSGList *qsg, DeviceState *dev, int alloc_hint,
+                      AddressSpace *as);
+void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len);
+void qemu_sglist_destroy(QEMUSGList *qsg);
+#endif
+
+typedef BlockAIOCB *DMAIOFunc(int64_t offset, QEMUIOVector *iov,
+                              BlockCompletionFunc *cb, void *cb_opaque,
+                              void *opaque);
+
+BlockAIOCB *dma_blk_io(AioContext *ctx,
+                       QEMUSGList *sg, uint64_t offset, uint32_t align,
+                       DMAIOFunc *io_func, void *io_func_opaque,
+                       BlockCompletionFunc *cb, void *opaque, DMADirection dir);
+BlockAIOCB *dma_blk_read(BlockBackend *blk,
+                         QEMUSGList *sg, uint64_t offset, uint32_t align,
+                         BlockCompletionFunc *cb, void *opaque);
+BlockAIOCB *dma_blk_write(BlockBackend *blk,
+                          QEMUSGList *sg, uint64_t offset, uint32_t align,
+                          BlockCompletionFunc *cb, void *opaque);
+uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg);
+uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg);
+
+void dma_acct_start(BlockBackend *blk, BlockAcctCookie *cookie,
+                    QEMUSGList *sg, enum BlockAcctType type);
+
+/**
+ * dma_aligned_pow2_mask: Return the address bit mask of the largest
+ * power of 2 size less or equal than @end - @start + 1, aligned with @start,
+ * and bounded by 1 << @max_addr_bits bits.
+ *
+ * @start: range start address
+ * @end: range end address (greater than @start)
+ * @max_addr_bits: max address bits (<= 64)
+ */
+uint64_t dma_aligned_pow2_mask(uint64_t start, uint64_t end,
+                               int max_addr_bits);
+
+#endif