Re: [Xen-devel] [PATCH] x86/hvm: fix saved pmtimer value
On Wed, Sep 09, 2015 at 01:46:35AM -0600, Jan Beulich wrote: > >>> On 09.09.15 at 09:31, wrote: > > The ACPI PM timer is sometimes broken on live migration. > > Since vcpu->arch.hvm_vcpu.guest_time is zero in most cases. > > I.e. in other than "delay for missed ticks mode". Would have been > nice if you had spelled this out explicitly. With that the question > then is - should the field perhaps be used when non-zero, and the > function only be called otherwise? > > Wei - regardless of the answer to the above (i.e. regardless of > whether a v2 is going to be needed) I think we want this in 4.6. > Yes. I think so. I will leave the technical side to you and Andy. Release-acked-by: Wei Liu > Jan ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH] x86/hvm: fix saved pmtimer value
>>> On 09.09.15 at 10:31, wrote: > Jan Beulich writes: > > On 09.09.15 at 09:31, wrote: >>> The ACPI PM timer is sometimes broken on live migration. >>> Since vcpu->arch.hvm_vcpu.guest_time is zero in most cases. >> >> I.e. in other than "delay for missed ticks mode". Would have been >> nice if you had spelled this out explicitly. > > Actually, I tried "delay for missed ticks mode" (timer_mode=0). > Even in this case, the pmtimer was broken. I don't know why. It would of course be helpful to understand why. >> With that the question then is - >> should the field perhaps be used when non-zero, and the >> function only be called otherwise? > > The adjustment of timer value in pmtimer_save() was introduced > before other timer_modes were implemented. > > I'm not sure (skeptical) the small adjustment is really necessary > in pmtimer_save. Together with the above, and with or without code adjustment, I'd then like to ask for a v2 with an improved description. And please don't forget to Cc maintainers of the code as well as Wei (the 4.6 release manager). Jan ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH] x86/hvm: fix saved pmtimer value
Jan Beulich writes: On 09.09.15 at 09:31, wrote: >> The ACPI PM timer is sometimes broken on live migration. >> Since vcpu->arch.hvm_vcpu.guest_time is zero in most cases. > > I.e. in other than "delay for missed ticks mode". Would have been > nice if you had spelled this out explicitly. Actually, I tried "delay for missed ticks mode" (timer_mode=0). Even in this case, the pmtimer was broken. I don't know why. > With that the question then is - > should the field perhaps be used when non-zero, and the > function only be called otherwise? The adjustment of timer value in pmtimer_save() was introduced before other timer_modes were implemented. I'm not sure (skeptical) the small adjustment is really necessary in pmtimer_save. Thanks, Kouya > > Wei - regardless of the answer to the above (i.e. regardless of > whether a v2 is going to be needed) I think we want this in 4.6. > > Jan ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
Re: [Xen-devel] [PATCH] x86/hvm: fix saved pmtimer value
>>> On 09.09.15 at 09:31, wrote: > The ACPI PM timer is sometimes broken on live migration. > Since vcpu->arch.hvm_vcpu.guest_time is zero in most cases. I.e. in other than "delay for missed ticks mode". Would have been nice if you had spelled this out explicitly. With that the question then is - should the field perhaps be used when non-zero, and the function only be called otherwise? Wei - regardless of the answer to the above (i.e. regardless of whether a v2 is going to be needed) I think we want this in 4.6. Jan ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
[Xen-devel] [PATCH] x86/hvm: fix saved pmtimer value
The ACPI PM timer is sometimes broken on live migration. Since vcpu->arch.hvm_vcpu.guest_time is zero in most cases. Without this patch, the clock of windows server 2012R2 without HPET might leap forward several minutes on live migration. Signed-off-by: Kouya Shimura --- xen/arch/x86/hvm/pmtimer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/xen/arch/x86/hvm/pmtimer.c b/xen/arch/x86/hvm/pmtimer.c index 07594e1..282efd0 100644 --- a/xen/arch/x86/hvm/pmtimer.c +++ b/xen/arch/x86/hvm/pmtimer.c @@ -252,7 +252,7 @@ static int pmtimer_save(struct domain *d, hvm_domain_context_t *h) /* Update the counter to the guest's current time. We always save * with the domain paused, so the saved time should be after the * last_gtime, but just in case, make sure we only go forwards */ -x = ((s->vcpu->arch.hvm_vcpu.guest_time - s->last_gtime) * s->scale) >> 32; +x = ((hvm_get_guest_time(s->vcpu) - s->last_gtime) * s->scale) >> 32; if ( x < 1UL<<31 ) s->pm.tmr_val += x; if ( (s->pm.tmr_val & TMR_VAL_MSB) != msb ) -- 1.9.1 ___ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
