x86: vdso: use __pvclock_read_cycles

The new simplified __pvclock_read_cycles does the same computation
as vread_pvclock, except that (because it takes the pvclock_vcpu_time_info
pointer) it has to be moved inside the loop.  Since the loop is expected to
never roll, this makes no difference.

Acked-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c
index db1e3b4..94d54d0 100644 (file)
--- a/arch/x86/entry/vdso/vclock_gettime.c
+++ b/arch/x86/entry/vdso/vclock_gettime.c
@@ -96,9 +96,8 @@ static notrace cycle_t vread_pvclock(int *mode)
 {
        const struct pvclock_vcpu_time_info *pvti = &get_pvti0()->pvti;
        cycle_t ret;
-       u64 tsc, pvti_tsc;
-       u64 last, delta, pvti_system_time;
-       u32 version, pvti_tsc_to_system_mul, pvti_tsc_shift;
+       u64 last;
+       u32 version;
 
        /*
         * Note: The kernel and hypervisor must guarantee that cpu ID
@@ -130,18 +129,9 @@ static notrace cycle_t vread_pvclock(int *mode)
                        return 0;
                }
 
-               tsc = rdtsc_ordered();
-               pvti_tsc_to_system_mul = pvti->tsc_to_system_mul;
-               pvti_tsc_shift = pvti->tsc_shift;
-               pvti_system_time = pvti->system_time;
-               pvti_tsc = pvti->tsc_timestamp;
+               ret = __pvclock_read_cycles(pvti);
        } while (pvclock_read_retry(pvti, version));
 
-       delta = tsc - pvti_tsc;
-       ret = pvti_system_time +
-               pvclock_scale_delta(delta, pvti_tsc_to_system_mul,
-                                   pvti_tsc_shift);
-
        /* refer to vread_tsc() comment for rationale */
        last = gtod->cycle_last;