bitmap: use indices

asamy · May 28, 2017 · fa654b6 · fa654b6
1 parent b895792
commit fa654b6
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Showing 2 changed files with 7 additions and 4 deletions.
diff --git a/bitmap.h b/bitmap.h
@@ -34,8 +34,8 @@
 #endif
 
 #define BITMAP_BITS			(sizeof(unsigned long) * CHAR_BIT)
-#define BIT_MASK(nr) 			(1UL << ((nr - 1) % BITMAP_BITS))
-#define BIT_WORD(nr) 			(((nr) - 1) / BITMAP_BITS)
+#define BIT_MASK(nr) 			(1UL << ((nr) % BITMAP_BITS))
+#define BIT_WORD(nr) 			((nr) / BITMAP_BITS)
 #define DECLARE_BITMAP(name, bits)	\
 	unsigned long name[DIV_ROUND_UP(bits, BITMAP_BITS)]
 
@@ -74,7 +74,7 @@ static inline unsigned long __ffs(unsigned long x)
 #ifdef _MSC_VER
 	unsigned long i;
 	_BitScanForward(&i, x);
-	return i + 1;
+	return i;
 #else
 	return __builtin_ffs(x);
 #endif
@@ -85,7 +85,7 @@ static inline unsigned long __ffz(unsigned long x)
 #ifdef _MSC_VER
 	unsigned long i;
 	_BitScanForward(&i, ~x);
-	return i + 1;
+	return i;
 #else
 	return __builtin_ffs(~x);
 #endif

diff --git a/vcpu.c b/vcpu.c
@@ -224,6 +224,9 @@ bool ept_create_ptr(struct ept *ept, int access, u16 *out)
 	if (eptp == EPT_MAX_EPTP_LIST)
 		return false;
 
+	/* find_first_zero_bit returns a number, not an index.  */
+	eptp--;
+
 	pml4 = &EPT4(ept, eptp);
 	if (!(*pml4 = mm_alloc_page()))
 		return false;