On 10/10/19 09:30, Suleiman Souhlal wrote:
> +kvm_hostclock_enable(struct clocksource *cs)
> +{
> + pv_timekeeper_enabled = 1;
> +
> + old_vclock_mode = kvm_clock.archdata.vclock_mode;
> + kvm_clock.archdata.vclock_mode = VCLOCK_TSC;
> + return 0;
> +}
> +
> +static void
> +kvm_hostclock_disable(struct clocksource *cs)
> +{
> + pv_timekeeper_enabled = 0;
> + kvm_clock.archdata.vclock_mode = old_vclock_mode;
> +}
> +
Why do you poke at kvm_clock? Instead you should add
.archdata = { .vclock_mode = VCLOCK_TSC },
to the kvm_hostclock declaration.
Please also check that the invariant TSC CPUID bit
CPUID[0x80000007].EDX[8] is set before enabling this feature.
Paolo
> + pvtk = &pv_timekeeper;
> + do {
> + gen = pvtk_read_begin(pvtk);
> + if (!(pv_timekeeper.flags & PVCLOCK_TIMEKEEPER_ENABLED))
> + return;
> +
> + pvclock_copy_into_read_base(pvtk, &tk->tkr_mono,
> + &pvtk->tkr_mono);
> + pvclock_copy_into_read_base(pvtk, &tk->tkr_raw, &pvtk->tkr_raw);
> +
> + tk->xtime_sec = pvtk->xtime_sec;
> + tk->ktime_sec = pvtk->ktime_sec;
> + tk->wall_to_monotonic.tv_sec = pvtk->wall_to_monotonic_sec;
> + tk->wall_to_monotonic.tv_nsec = pvtk->wall_to_monotonic_nsec;
> + tk->offs_real = pvtk->offs_real;
> + tk->offs_boot = pvtk->offs_boot;
> + tk->offs_tai = pvtk->offs_tai;
> + tk->raw_sec = pvtk->raw_sec;
> + } while (pvtk_read_retry(pvtk, gen));
> +}
> +
Should you write an "enabled value" (basically the flags) into pvtk as well?
>
> +kvm_hostclock_init(void)
> +{
> + unsigned long pa;
> +
> + pa = __pa(&pv_timekeeper);
> + wrmsrl(MSR_KVM_TIMEKEEPER_EN, pa);
As Vitaly said, a new CPUID bit must be defined in
Documentation/virt/kvm/cpuid.txt, and used here. Also please make bit 0
an enable bit.
