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, 489 insertions, 0 deletions

diff --git a/util/bitmap.c b/util/bitmap.c
new file mode 100644
index 000000000..1f201393a
--- /dev/null
+++ b/util/bitmap.c
@@ -0,0 +1,489 @@
+/*
+ * Bitmap Module
+ *
+ * Stolen from linux/src/lib/bitmap.c
+ *
+ * Copyright (C) 2010 Corentin Chary
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/bitops.h"
+#include "qemu/bitmap.h"
+#include "qemu/atomic.h"
+
+/*
+ * bitmaps provide an array of bits, implemented using an
+ * array of unsigned longs.  The number of valid bits in a
+ * given bitmap does _not_ need to be an exact multiple of
+ * BITS_PER_LONG.
+ *
+ * The possible unused bits in the last, partially used word
+ * of a bitmap are 'don't care'.  The implementation makes
+ * no particular effort to keep them zero.  It ensures that
+ * their value will not affect the results of any operation.
+ * The bitmap operations that return Boolean (bitmap_empty,
+ * for example) or scalar (bitmap_weight, for example) results
+ * carefully filter out these unused bits from impacting their
+ * results.
+ *
+ * These operations actually hold to a slightly stronger rule:
+ * if you don't input any bitmaps to these ops that have some
+ * unused bits set, then they won't output any set unused bits
+ * in output bitmaps.
+ *
+ * The byte ordering of bitmaps is more natural on little
+ * endian architectures.
+ */
+
+int slow_bitmap_empty(const unsigned long *bitmap, long bits)
+{
+    long k, lim = bits/BITS_PER_LONG;
+
+    for (k = 0; k < lim; ++k) {
+        if (bitmap[k]) {
+            return 0;
+        }
+    }
+    if (bits % BITS_PER_LONG) {
+        if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits)) {
+            return 0;
+        }
+    }
+
+    return 1;
+}
+
+int slow_bitmap_full(const unsigned long *bitmap, long bits)
+{
+    long k, lim = bits/BITS_PER_LONG;
+
+    for (k = 0; k < lim; ++k) {
+        if (~bitmap[k]) {
+            return 0;
+        }
+    }
+
+    if (bits % BITS_PER_LONG) {
+        if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits)) {
+            return 0;
+        }
+    }
+
+    return 1;
+}
+
+int slow_bitmap_equal(const unsigned long *bitmap1,
+                      const unsigned long *bitmap2, long bits)
+{
+    long k, lim = bits/BITS_PER_LONG;
+
+    for (k = 0; k < lim; ++k) {
+        if (bitmap1[k] != bitmap2[k]) {
+            return 0;
+        }
+    }
+
+    if (bits % BITS_PER_LONG) {
+        if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) {
+            return 0;
+        }
+    }
+
+    return 1;
+}
+
+void slow_bitmap_complement(unsigned long *dst, const unsigned long *src,
+                            long bits)
+{
+    long k, lim = bits/BITS_PER_LONG;
+
+    for (k = 0; k < lim; ++k) {
+        dst[k] = ~src[k];
+    }
+
+    if (bits % BITS_PER_LONG) {
+        dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
+    }
+}
+
+int slow_bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
+                    const unsigned long *bitmap2, long bits)
+{
+    long k;
+    long nr = BITS_TO_LONGS(bits);
+    unsigned long result = 0;
+
+    for (k = 0; k < nr; k++) {
+        result |= (dst[k] = bitmap1[k] & bitmap2[k]);
+    }
+    return result != 0;
+}
+
+void slow_bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
+                    const unsigned long *bitmap2, long bits)
+{
+    long k;
+    long nr = BITS_TO_LONGS(bits);
+
+    for (k = 0; k < nr; k++) {
+        dst[k] = bitmap1[k] | bitmap2[k];
+    }
+}
+
+void slow_bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
+                     const unsigned long *bitmap2, long bits)
+{
+    long k;
+    long nr = BITS_TO_LONGS(bits);
+
+    for (k = 0; k < nr; k++) {
+        dst[k] = bitmap1[k] ^ bitmap2[k];
+    }
+}
+
+int slow_bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
+                       const unsigned long *bitmap2, long bits)
+{
+    long k;
+    long nr = BITS_TO_LONGS(bits);
+    unsigned long result = 0;
+
+    for (k = 0; k < nr; k++) {
+        result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
+    }
+    return result != 0;
+}
+
+void bitmap_set(unsigned long *map, long start, long nr)
+{
+    unsigned long *p = map + BIT_WORD(start);
+    const long size = start + nr;
+    int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
+    unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
+
+    assert(start >= 0 && nr >= 0);
+
+    while (nr - bits_to_set >= 0) {
+        *p |= mask_to_set;
+        nr -= bits_to_set;
+        bits_to_set = BITS_PER_LONG;
+        mask_to_set = ~0UL;
+        p++;
+    }
+    if (nr) {
+        mask_to_set &= BITMAP_LAST_WORD_MASK(size);
+        *p |= mask_to_set;
+    }
+}
+
+void bitmap_set_atomic(unsigned long *map, long start, long nr)
+{
+    unsigned long *p = map + BIT_WORD(start);
+    const long size = start + nr;
+    int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
+    unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
+
+    assert(start >= 0 && nr >= 0);
+
+    /* First word */
+    if (nr - bits_to_set > 0) {
+        qatomic_or(p, mask_to_set);
+        nr -= bits_to_set;
+        bits_to_set = BITS_PER_LONG;
+        mask_to_set = ~0UL;
+        p++;
+    }
+
+    /* Full words */
+    if (bits_to_set == BITS_PER_LONG) {
+        while (nr >= BITS_PER_LONG) {
+            *p = ~0UL;
+            nr -= BITS_PER_LONG;
+            p++;
+        }
+    }
+
+    /* Last word */
+    if (nr) {
+        mask_to_set &= BITMAP_LAST_WORD_MASK(size);
+        qatomic_or(p, mask_to_set);
+    } else {
+        /* If we avoided the full barrier in qatomic_or(), issue a
+         * barrier to account for the assignments in the while loop.
+         */
+        smp_mb();
+    }
+}
+
+void bitmap_clear(unsigned long *map, long start, long nr)
+{
+    unsigned long *p = map + BIT_WORD(start);
+    const long size = start + nr;
+    int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
+    unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
+
+    assert(start >= 0 && nr >= 0);
+
+    while (nr - bits_to_clear >= 0) {
+        *p &= ~mask_to_clear;
+        nr -= bits_to_clear;
+        bits_to_clear = BITS_PER_LONG;
+        mask_to_clear = ~0UL;
+        p++;
+    }
+    if (nr) {
+        mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
+        *p &= ~mask_to_clear;
+    }
+}
+
+bool bitmap_test_and_clear_atomic(unsigned long *map, long start, long nr)
+{
+    unsigned long *p = map + BIT_WORD(start);
+    const long size = start + nr;
+    int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
+    unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
+    unsigned long dirty = 0;
+    unsigned long old_bits;
+
+    assert(start >= 0 && nr >= 0);
+
+    /* First word */
+    if (nr - bits_to_clear > 0) {
+        old_bits = qatomic_fetch_and(p, ~mask_to_clear);
+        dirty |= old_bits & mask_to_clear;
+        nr -= bits_to_clear;
+        bits_to_clear = BITS_PER_LONG;
+        mask_to_clear = ~0UL;
+        p++;
+    }
+
+    /* Full words */
+    if (bits_to_clear == BITS_PER_LONG) {
+        while (nr >= BITS_PER_LONG) {
+            if (*p) {
+                old_bits = qatomic_xchg(p, 0);
+                dirty |= old_bits;
+            }
+            nr -= BITS_PER_LONG;
+            p++;
+        }
+    }
+
+    /* Last word */
+    if (nr) {
+        mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
+        old_bits = qatomic_fetch_and(p, ~mask_to_clear);
+        dirty |= old_bits & mask_to_clear;
+    } else {
+        if (!dirty) {
+            smp_mb();
+        }
+    }
+
+    return dirty != 0;
+}
+
+void bitmap_copy_and_clear_atomic(unsigned long *dst, unsigned long *src,
+                                  long nr)
+{
+    while (nr > 0) {
+        *dst = qatomic_xchg(src, 0);
+        dst++;
+        src++;
+        nr -= BITS_PER_LONG;
+    }
+}
+
+#define ALIGN_MASK(x,mask)      (((x)+(mask))&~(mask))
+
+/**
+ * bitmap_find_next_zero_area - find a contiguous aligned zero area
+ * @map: The address to base the search on
+ * @size: The bitmap size in bits
+ * @start: The bitnumber to start searching at
+ * @nr: The number of zeroed bits we're looking for
+ * @align_mask: Alignment mask for zero area
+ *
+ * The @align_mask should be one less than a power of 2; the effect is that
+ * the bit offset of all zero areas this function finds is multiples of that
+ * power of 2. A @align_mask of 0 means no alignment is required.
+ */
+unsigned long bitmap_find_next_zero_area(unsigned long *map,
+                                         unsigned long size,
+                                         unsigned long start,
+                                         unsigned long nr,
+                                         unsigned long align_mask)
+{
+    unsigned long index, end, i;
+again:
+    index = find_next_zero_bit(map, size, start);
+
+    /* Align allocation */
+    index = ALIGN_MASK(index, align_mask);
+
+    end = index + nr;
+    if (end > size) {
+        return end;
+    }
+    i = find_next_bit(map, end, index);
+    if (i < end) {
+        start = i + 1;
+        goto again;
+    }
+    return index;
+}
+
+int slow_bitmap_intersects(const unsigned long *bitmap1,
+                           const unsigned long *bitmap2, long bits)
+{
+    long k, lim = bits/BITS_PER_LONG;
+
+    for (k = 0; k < lim; ++k) {
+        if (bitmap1[k] & bitmap2[k]) {
+            return 1;
+        }
+    }
+
+    if (bits % BITS_PER_LONG) {
+        if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) {
+            return 1;
+        }
+    }
+    return 0;
+}
+
+long slow_bitmap_count_one(const unsigned long *bitmap, long nbits)
+{
+    long k, lim = nbits / BITS_PER_LONG, result = 0;
+
+    for (k = 0; k < lim; k++) {
+        result += ctpopl(bitmap[k]);
+    }
+
+    if (nbits % BITS_PER_LONG) {
+        result += ctpopl(bitmap[k] & BITMAP_LAST_WORD_MASK(nbits));
+    }
+
+    return result;
+}
+
+static void bitmap_to_from_le(unsigned long *dst,
+                              const unsigned long *src, long nbits)
+{
+    long len = BITS_TO_LONGS(nbits);
+
+#ifdef HOST_WORDS_BIGENDIAN
+    long index;
+
+    for (index = 0; index < len; index++) {
+# if HOST_LONG_BITS == 64
+        dst[index] = bswap64(src[index]);
+# else
+        dst[index] = bswap32(src[index]);
+# endif
+    }
+#else
+    memcpy(dst, src, len * sizeof(unsigned long));
+#endif
+}
+
+void bitmap_from_le(unsigned long *dst, const unsigned long *src,
+                    long nbits)
+{
+    bitmap_to_from_le(dst, src, nbits);
+}
+
+void bitmap_to_le(unsigned long *dst, const unsigned long *src,
+                  long nbits)
+{
+    bitmap_to_from_le(dst, src, nbits);
+}
+
+/*
+ * Copy "src" bitmap with a positive offset and put it into the "dst"
+ * bitmap.  The caller needs to make sure the bitmap size of "src"
+ * is bigger than (shift + nbits).
+ */
+void bitmap_copy_with_src_offset(unsigned long *dst, const unsigned long *src,
+                                 unsigned long shift, unsigned long nbits)
+{
+    unsigned long left_mask, right_mask, last_mask;
+
+    /* Proper shift src pointer to the first word to copy from */
+    src += BIT_WORD(shift);
+    shift %= BITS_PER_LONG;
+
+    if (!shift) {
+        /* Fast path */
+        bitmap_copy(dst, src, nbits);
+        return;
+    }
+
+    right_mask = (1ul << shift) - 1;
+    left_mask = ~right_mask;
+
+    while (nbits >= BITS_PER_LONG) {
+        *dst = (*src & left_mask) >> shift;
+        *dst |= (src[1] & right_mask) << (BITS_PER_LONG - shift);
+        dst++;
+        src++;
+        nbits -= BITS_PER_LONG;
+    }
+
+    if (nbits > BITS_PER_LONG - shift) {
+        *dst = (*src & left_mask) >> shift;
+        nbits -= BITS_PER_LONG - shift;
+        last_mask = (1ul << nbits) - 1;
+        *dst |= (src[1] & last_mask) << (BITS_PER_LONG - shift);
+    } else if (nbits) {
+        last_mask = (1ul << nbits) - 1;
+        *dst = (*src >> shift) & last_mask;
+    }
+}
+
+/*
+ * Copy "src" bitmap into the "dst" bitmap with an offset in the
+ * "dst".  The caller needs to make sure the bitmap size of "dst" is
+ * bigger than (shift + nbits).
+ */
+void bitmap_copy_with_dst_offset(unsigned long *dst, const unsigned long *src,
+                                 unsigned long shift, unsigned long nbits)
+{
+    unsigned long left_mask, right_mask, last_mask;
+
+    /* Proper shift dst pointer to the first word to copy from */
+    dst += BIT_WORD(shift);
+    shift %= BITS_PER_LONG;
+
+    if (!shift) {
+        /* Fast path */
+        bitmap_copy(dst, src, nbits);
+        return;
+    }
+
+    right_mask = (1ul << (BITS_PER_LONG - shift)) - 1;
+    left_mask = ~right_mask;
+
+    *dst &= (1ul << shift) - 1;
+    while (nbits >= BITS_PER_LONG) {
+        *dst |= (*src & right_mask) << shift;
+        dst[1] = (*src & left_mask) >> (BITS_PER_LONG - shift);
+        dst++;
+        src++;
+        nbits -= BITS_PER_LONG;
+    }
+
+    if (nbits > BITS_PER_LONG - shift) {
+        *dst |= (*src & right_mask) << shift;
+        nbits -= BITS_PER_LONG - shift;
+        last_mask = ((1ul << nbits) - 1) << (BITS_PER_LONG - shift);
+        dst[1] = (*src & last_mask) >> (BITS_PER_LONG - shift);
+    } else if (nbits) {
+        last_mask = (1ul << nbits) - 1;
+        *dst |= (*src & last_mask) << shift;
+    }
+}