diff options
| -rw-r--r-- | arch/x86/kvm/x86.c | 10 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.h | 15 |
2 files changed, 17 insertions, 8 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4244c2baf57d..5b937fdebc66 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1196,14 +1196,8 @@ static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock) static uint32_t div_frac(uint32_t dividend, uint32_t divisor) { - uint32_t quotient, remainder; - - /* Don't try to replace with do_div(), this one calculates - * "(dividend << 32) / divisor" */ - __asm__ ( "divl %4" - : "=a" (quotient), "=d" (remainder) - : "0" (0), "1" (dividend), "r" (divisor) ); - return quotient; + do_shl32_div32(dividend, divisor); + return dividend; } static void kvm_get_time_scale(uint32_t scaled_khz, uint32_t base_khz, diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index f2afa5fe48a6..34f416427143 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -192,4 +192,19 @@ extern unsigned int min_timer_period_us; extern unsigned int lapic_timer_advance_ns; extern struct static_key kvm_no_apic_vcpu; + +/* Same "calling convention" as do_div: + * - divide (n << 32) by base + * - put result in n + * - return remainder + */ +#define do_shl32_div32(n, base) \ + ({ \ + u32 __quot, __rem; \ + asm("divl %2" : "=a" (__quot), "=d" (__rem) \ + : "rm" (base), "0" (0), "1" ((u32) n)); \ + n = __quot; \ + __rem; \ + }) + #endif |