[PATCH kvmtool 7/9] util: Add cpulist_parse()
Alexandru Elisei
alexandru.elisei at arm.com
Mon Nov 15 08:57:03 PST 2021
Add the function cpulist_parse(), which creates a cpumask_t from a
cpulist. The function will be necessary to parse the cpulist of CPUs
associated with a particular PMU.
Signed-off-by: Alexandru Elisei <alexandru.elisei at arm.com>
---
Makefile | 1 +
include/linux/bitmap.h | 25 +++++
include/linux/bitops.h | 2 +
include/linux/cpumask.h | 5 +
include/linux/kernel.h | 1 +
util/bitmap.c | 221 ++++++++++++++++++++++++++++++++++++++++
6 files changed, 255 insertions(+)
create mode 100644 util/bitmap.c
diff --git a/Makefile b/Makefile
index c7820e6a5200..3f65d6b0478d 100644
--- a/Makefile
+++ b/Makefile
@@ -88,6 +88,7 @@ OBJS += net/uip/buf.o
OBJS += net/uip/csum.o
OBJS += net/uip/dhcp.o
OBJS += kvm-cmd.o
+OBJS += util/bitmap.o
OBJS += util/init.o
OBJS += util/iovec.o
OBJS += util/rbtree.o
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 33b24520a576..3221d06d9200 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -17,4 +17,29 @@ static inline void bitmap_zero(unsigned long *dst, unsigned int nbits)
memset(dst, 0, len);
}
+#ifdef __LITTLE_ENDIAN
+#define BITMAP_MEM_ALIGNMENT 8
+#else
+#define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long))
+#endif
+#define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1)
+
+void __bitmap_set(unsigned long *map, unsigned int start, int len);
+
+static inline void bitmap_set(unsigned long *map, unsigned int start,
+ unsigned int nbits)
+{
+ if (__builtin_constant_p(nbits) && nbits == 1)
+ set_bit(start, map);
+ else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
+ IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
+ __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
+ IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
+ memset((char *)map + start / 8, 0xff, nbits / 8);
+ else
+ __bitmap_set(map, start, nbits);
+}
+
+int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits);
+
#endif /* KVM__BITMAP_H */
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 56448b71ebbf..d8df5515ceb8 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -9,6 +9,8 @@
#define BITS_PER_BYTE 8
#define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
+#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
+
static inline void set_bit(int nr, unsigned long *addr)
{
addr[nr / BITS_PER_LONG] |= 1UL << (nr % BITS_PER_LONG);
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 36959885aeff..25c11b0361ec 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -30,4 +30,9 @@ static inline void cpumask_clear(cpumask_t *dstp)
bitmap_zero(cpumask_bits(dstp), NR_CPUS);
}
+static inline int cpulist_parse(const char *buf, cpumask_t *dstp)
+{
+ return bitmap_parselist(buf, cpumask_bits(dstp), NR_CPUS);
+}
+
#endif /* KVM__CPUMASK_H */
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index f3240e09a321..0b9079f9c0bc 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -8,6 +8,7 @@
#define ALIGN(x,a) __ALIGN_MASK(x,(typeof(x))(a)-1)
#define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask))
+#define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
#ifndef offsetof
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
diff --git a/util/bitmap.c b/util/bitmap.c
new file mode 100644
index 000000000000..eef23d0f1845
--- /dev/null
+++ b/util/bitmap.c
@@ -0,0 +1,221 @@
+/*
+ * Taken from Linux kernel version v5.15.
+ */
+#include <ctype.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <strings.h>
+
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <linux/err.h>
+
+/*
+ * Region 9-38:4/10 describes the following bitmap structure:
+ * 0 9 12 18 38 N
+ * .........****......****......****..................
+ * ^ ^ ^ ^ ^
+ * start off group_len end nbits
+ */
+struct region {
+ unsigned int start;
+ unsigned int off;
+ unsigned int group_len;
+ unsigned int end;
+ unsigned int nbits;
+};
+
+void __bitmap_set(unsigned long *map, unsigned int start, int len)
+{
+ unsigned long *p = map + BIT_WORD(start);
+ const unsigned int size = start + len;
+ int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
+ unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
+
+ while (len - bits_to_set >= 0) {
+ *p |= mask_to_set;
+ len -= bits_to_set;
+ bits_to_set = BITS_PER_LONG;
+ mask_to_set = ~0UL;
+ p++;
+ }
+ if (len) {
+ mask_to_set &= BITMAP_LAST_WORD_MASK(size);
+ *p |= mask_to_set;
+ }
+}
+
+static void bitmap_set_region(const struct region *r, unsigned long *bitmap)
+{
+ unsigned int start;
+
+ for (start = r->start; start <= r->end; start += r->group_len)
+ bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
+}
+
+static inline bool __end_of_region(char c)
+{
+ return isspace(c) || c == ',';
+}
+
+static inline bool end_of_str(char c)
+{
+ return c == '\0' || c == '\n';
+}
+
+static inline bool end_of_region(char c)
+{
+ return __end_of_region(c) || end_of_str(c);
+}
+
+/*
+ * The format allows commas and whitespaces at the beginning
+ * of the region.
+ */
+static const char *bitmap_find_region(const char *str)
+{
+ while (__end_of_region(*str))
+ str++;
+
+ return end_of_str(*str) ? NULL : str;
+}
+
+static int bitmap_check_region(const struct region *r)
+{
+ if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
+ return -EINVAL;
+
+ if (r->end >= r->nbits)
+ return -ERANGE;
+
+ return 0;
+}
+
+static const char *bitmap_getnum(const char *str, unsigned int *num,
+ unsigned int lastbit)
+{
+ unsigned long long n;
+ char *endptr;
+
+ if (str[0] == 'N') {
+ *num = lastbit;
+ return str + 1;
+ }
+
+ n = strtoll(str, &endptr, 10);
+ /* No digits found. */
+ if (n == 0 && endptr == str)
+ return ERR_PTR(-EINVAL);
+ /* Check for overflows and negative numbers. */
+ if (n == ULLONG_MAX || n != (unsigned long)n || n != (unsigned int)n)
+ return ERR_PTR(-EOVERFLOW);
+
+ *num = n;
+ return endptr;
+}
+
+static const char *bitmap_parse_region(const char *str, struct region *r)
+{
+ unsigned int lastbit = r->nbits - 1;
+
+ if (!strncasecmp(str, "all", 3)) {
+ r->start = 0;
+ r->end = lastbit;
+ str += 3;
+
+ goto check_pattern;
+ }
+
+ str = bitmap_getnum(str, &r->start, lastbit);
+ if (IS_ERR(str))
+ return str;
+
+ if (end_of_region(*str))
+ goto no_end;
+
+ if (*str != '-')
+ return ERR_PTR(-EINVAL);
+
+ str = bitmap_getnum(str + 1, &r->end, lastbit);
+ if (IS_ERR(str))
+ return str;
+
+check_pattern:
+ if (end_of_region(*str))
+ goto no_pattern;
+
+ if (*str != ':')
+ return ERR_PTR(-EINVAL);
+
+ str = bitmap_getnum(str + 1, &r->off, lastbit);
+ if (IS_ERR(str))
+ return str;
+
+ if (*str != '/')
+ return ERR_PTR(-EINVAL);
+
+ return bitmap_getnum(str + 1, &r->group_len, lastbit);
+
+no_end:
+ r->end = r->start;
+no_pattern:
+ r->off = r->end + 1;
+ r->group_len = r->end + 1;
+
+ return end_of_str(*str) ? NULL : str;
+}
+
+/**
+ * bitmap_parselist - convert list format ASCII string to bitmap
+ * @buf: read user string from this buffer; must be terminated
+ * with a \0 or \n.
+ * @maskp: write resulting mask here
+ * @nmaskbits: number of bits in mask to be written
+ *
+ * Input format is a comma-separated list of decimal numbers and
+ * ranges. Consecutively set bits are shown as two hyphen-separated
+ * decimal numbers, the smallest and largest bit numbers set in
+ * the range.
+ * Optionally each range can be postfixed to denote that only parts of it
+ * should be set. The range will divided to groups of specific size.
+ * From each group will be used only defined amount of bits.
+ * Syntax: range:used_size/group_size
+ * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
+ * The value 'N' can be used as a dynamically substituted token for the
+ * maximum allowed value; i.e (nmaskbits - 1). Keep in mind that it is
+ * dynamic, so if system changes cause the bitmap width to change, such
+ * as more cores in a CPU list, then any ranges using N will also change.
+ *
+ * Returns: 0 on success, -errno on invalid input strings. Error values:
+ *
+ * - ``-EINVAL``: wrong region format
+ * - ``-EINVAL``: invalid character in string
+ * - ``-ERANGE``: bit number specified too large for mask
+ * - ``-EOVERFLOW``: integer overflow in the input parameters
+ */
+int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
+{
+ struct region r;
+ long ret;
+
+ r.nbits = nmaskbits;
+ bitmap_zero(maskp, r.nbits);
+
+ while (buf) {
+ buf = bitmap_find_region(buf);
+ if (buf == NULL)
+ return 0;
+
+ buf = bitmap_parse_region(buf, &r);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ ret = bitmap_check_region(&r);
+ if (ret)
+ return ret;
+
+ bitmap_set_region(&r, maskp);
+ }
+
+ return 0;
+}
--
2.31.1
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