diff options
Diffstat (limited to 'arch/x86/kvm/lapic.c')
| -rw-r--r-- | arch/x86/kvm/lapic.c | 30 |
1 files changed, 18 insertions, 12 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 07ad628dadb..6f9fd633c88 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -66,6 +66,7 @@ #define APIC_DEST_NOSHORT 0x0 #define APIC_DEST_MASK 0x800 #define MAX_APIC_VECTOR 256 +#define APIC_VECTORS_PER_REG 32 #define VEC_POS(v) ((v) & (32 - 1)) #define REG_POS(v) (((v) >> 5) << 4) @@ -208,25 +209,30 @@ static const unsigned int apic_lvt_mask[APIC_LVT_NUM] = { static int find_highest_vector(void *bitmap) { - u32 *word = bitmap; - int word_offset = MAX_APIC_VECTOR >> 5; + int vec; + u32 *reg; - while ((word_offset != 0) && (word[(--word_offset) << 2] == 0)) - continue; + for (vec = MAX_APIC_VECTOR - APIC_VECTORS_PER_REG; + vec >= 0; vec -= APIC_VECTORS_PER_REG) { + reg = bitmap + REG_POS(vec); + if (*reg) + return fls(*reg) - 1 + vec; + } - if (likely(!word_offset && !word[0])) - return -1; - else - return fls(word[word_offset << 2]) - 1 + (word_offset << 5); + return -1; } static u8 count_vectors(void *bitmap) { - u32 *word = bitmap; - int word_offset; + int vec; + u32 *reg; u8 count = 0; - for (word_offset = 0; word_offset < MAX_APIC_VECTOR >> 5; ++word_offset) - count += hweight32(word[word_offset << 2]); + + for (vec = 0; vec < MAX_APIC_VECTOR; vec += APIC_VECTORS_PER_REG) { + reg = bitmap + REG_POS(vec); + count += hweight32(*reg); + } + return count; } |