Signed-off-by: Gerd Hoffmann <[EMAIL PROTECTED]>
---
 arch/x86/kvm/x86.c |   63 +++++++++++++++++++++++++++++++++++++++++++--------
 1 files changed, 53 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 979f983..6906d54 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -493,7 +493,7 @@ static void kvm_write_wall_clock(struct kvm *kvm, gpa_t 
wall_clock)
 {
        static int version;
        struct kvm_wall_clock wc;
-       struct timespec wc_ts;
+       struct timespec now,sys,boot;
 
        if (!wall_clock)
                return;
@@ -502,9 +502,16 @@ static void kvm_write_wall_clock(struct kvm *kvm, gpa_t 
wall_clock)
 
        kvm_write_guest(kvm, wall_clock, &version, sizeof(version));
 
-       wc_ts = current_kernel_time();
-       wc.wc_sec = wc_ts.tv_sec;
-       wc.wc_nsec = wc_ts.tv_nsec;
+#if 0
+       /* Hmm, getboottime() isn't exported to modules ... */
+       getboottime(&boot);
+#else
+       now = current_kernel_time();
+       ktime_get_ts(&sys);
+       boot = ns_to_timespec(timespec_to_ns(&now) - timespec_to_ns(&sys));
+#endif
+       wc.wc_sec = boot.tv_sec;
+       wc.wc_nsec = boot.tv_nsec;
        wc.wc_version = version;
 
        kvm_write_guest(kvm, wall_clock, &wc, sizeof(wc));
@@ -537,20 +544,58 @@ static void kvm_write_guest_time(struct kvm_vcpu *v)
        /*
         * The interface expects us to write an even number signaling that the
         * update is finished. Since the guest won't see the intermediate
-        * state, we just write "2" at the end
+        * state, we just increase by 2 at the end.
         */
-       vcpu->hv_clock.version = 2;
+       vcpu->hv_clock.version += 2;
 
        shared_kaddr = kmap_atomic(vcpu->time_page, KM_USER0);
 
        memcpy(shared_kaddr + vcpu->time_offset, &vcpu->hv_clock,
-               sizeof(vcpu->hv_clock));
+              sizeof(vcpu->hv_clock));
 
        kunmap_atomic(shared_kaddr, KM_USER0);
 
        mark_page_dirty(v->kvm, vcpu->time >> PAGE_SHIFT);
 }
 
+static uint32_t div_frac(uint32_t dividend, uint32_t divisor)
+{
+       uint32_t quotient, remainder;
+
+       __asm__ ( "divl %4"
+                 : "=a" (quotient), "=d" (remainder)
+                 : "0" (0), "1" (dividend), "r" (divisor) );
+       return quotient;
+}
+
+static void kvm_set_time_scale(uint32_t tsc_khz, struct kvm_vcpu_time_info 
*hv_clock)
+{
+       uint64_t nsecs = 1000000000LL;
+       int32_t  shift = 0;
+       uint64_t tps64;
+       uint32_t tps32;
+
+       tps64 = tsc_khz * 1000LL;
+       while (tps64 > nsecs*2) {
+               tps64 >>= 1;
+               shift--;
+       }
+
+       tps32 = (uint32_t)tps64;
+       while (tps32 <= (uint32_t)nsecs) {
+               tps32 <<= 1;
+               shift++;
+       }
+
+       hv_clock->tsc_shift = shift;
+       hv_clock->tsc_to_system_mul = div_frac(nsecs, tps32);
+
+#if 0
+       printk(KERN_DEBUG "%s: tsc_khz %u, tsc_shift %d, tsc_mul %u\n",
+              __FUNCTION__, tsc_khz, hv_clock->tsc_shift,
+              hv_clock->tsc_to_system_mul);
+#endif
+}
 
 int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
 {
@@ -599,9 +644,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 
data)
                /* ...but clean it before doing the actual write */
                vcpu->arch.time_offset = data & ~(PAGE_MASK | 1);
 
-               vcpu->arch.hv_clock.tsc_to_system_mul =
-                                       clocksource_khz2mult(tsc_khz, 22);
-               vcpu->arch.hv_clock.tsc_shift = 22;
+               kvm_set_time_scale(tsc_khz, &vcpu->arch.hv_clock);
 
                down_read(&current->mm->mmap_sem);
                vcpu->arch.time_page =
-- 
1.5.4.1


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