On Tue, 2014-01-07 at 18:52 +0100, Peter Lieven wrote: > Am 07.01.2014 10:36, schrieb Vadim Rozenfeld: > > On Thu, 2014-01-02 at 17:52 +0100, Peter Lieven wrote: > >> Am 11.12.2013 19:59, schrieb Marcelo Tosatti: > >>> On Wed, Dec 11, 2013 at 04:53:05PM -0200, Marcelo Tosatti wrote: > >>>> On Sun, Dec 08, 2013 at 10:33:38PM +1100, Vadim Rozenfeld wrote: > >>>>> Signed-off: Peter Lieven <p...@dlh.net> > >>>>> Signed-off: Gleb Natapov <g...@redhat.com> > >>>>> Signed-off: Vadim Rozenfeld <vroze...@redhat.com> > >>>>> > >>>>> v1 -> v2 > >>>>> 1. mark TSC page dirty as suggested by > >>>>> Eric Northup <digitale...@google.com> and Gleb > >>>>> 2. disable local irq when calling get_kernel_ns, > >>>>> as it was done by Peter Lieven <p...@dlhnet.de> > >>>>> 3. move check for TSC page enable from second patch > >>>>> to this one. > >>>>> > >>>>> --- > >>>>> arch/x86/include/asm/kvm_host.h | 2 ++ > >>>>> arch/x86/include/uapi/asm/hyperv.h | 13 +++++++++++++ > >>>>> arch/x86/kvm/x86.c | 39 > >>>>> +++++++++++++++++++++++++++++++++++++- > >>>>> include/uapi/linux/kvm.h | 1 + > >>>>> 4 files changed, 54 insertions(+), 1 deletion(-) > >>>>> > >>>>> diff --git a/arch/x86/include/asm/kvm_host.h > >>>>> b/arch/x86/include/asm/kvm_host.h > >>>>> index ae5d783..2fd0753 100644 > >>>>> --- a/arch/x86/include/asm/kvm_host.h > >>>>> +++ b/arch/x86/include/asm/kvm_host.h > >>>>> @@ -605,6 +605,8 @@ struct kvm_arch { > >>>>> /* fields used by HYPER-V emulation */ > >>>>> u64 hv_guest_os_id; > >>>>> u64 hv_hypercall; > >>>>> + u64 hv_ref_count; > >>>>> + u64 hv_tsc_page; > >>>>> > >>>>> #ifdef CONFIG_KVM_MMU_AUDIT > >>>>> int audit_point; > >>>>> diff --git a/arch/x86/include/uapi/asm/hyperv.h > >>>>> b/arch/x86/include/uapi/asm/hyperv.h > >>>>> index b8f1c01..462efe7 100644 > >>>>> --- a/arch/x86/include/uapi/asm/hyperv.h > >>>>> +++ b/arch/x86/include/uapi/asm/hyperv.h > >>>>> @@ -28,6 +28,9 @@ > >>>>> /* Partition Reference Counter (HV_X64_MSR_TIME_REF_COUNT) available*/ > >>>>> #define HV_X64_MSR_TIME_REF_COUNT_AVAILABLE (1 << 1) > >>>>> > >>>>> +/* A partition's reference time stamp counter (TSC) page */ > >>>>> +#define HV_X64_MSR_REFERENCE_TSC 0x40000021 > >>>>> + > >>>>> /* > >>>>> * There is a single feature flag that signifies the presence of the > >>>>> MSR > >>>>> * that can be used to retrieve both the local APIC Timer frequency as > >>>>> @@ -198,6 +201,9 @@ > >>>>> #define HV_X64_MSR_APIC_ASSIST_PAGE_ADDRESS_MASK \ > >>>>> (~((1ull << HV_X64_MSR_APIC_ASSIST_PAGE_ADDRESS_SHIFT) > >>>>> - 1)) > >>>>> > >>>>> +#define HV_X64_MSR_TSC_REFERENCE_ENABLE 0x00000001 > >>>>> +#define HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT 12 > >>>>> + > >>>>> #define HV_PROCESSOR_POWER_STATE_C0 0 > >>>>> #define HV_PROCESSOR_POWER_STATE_C1 1 > >>>>> #define HV_PROCESSOR_POWER_STATE_C2 2 > >>>>> @@ -210,4 +216,11 @@ > >>>>> #define HV_STATUS_INVALID_ALIGNMENT 4 > >>>>> #define HV_STATUS_INSUFFICIENT_BUFFERS 19 > >>>>> > >>>>> +typedef struct _HV_REFERENCE_TSC_PAGE { > >>>>> + __u32 tsc_sequence; > >>>>> + __u32 res1; > >>>>> + __u64 tsc_scale; > >>>>> + __s64 tsc_offset; > >>>>> +} HV_REFERENCE_TSC_PAGE, *PHV_REFERENCE_TSC_PAGE; > >>>>> + > >>>>> #endif > >>>>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > >>>>> index 21ef1ba..5e4e495a 100644 > >>>>> --- a/arch/x86/kvm/x86.c > >>>>> +++ b/arch/x86/kvm/x86.c > >>>>> @@ -840,7 +840,7 @@ EXPORT_SYMBOL_GPL(kvm_rdpmc); > >>>>> static u32 msrs_to_save[] = { > >>>>> MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK, > >>>>> MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW, > >>>>> - HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL, > >>>>> + HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL, > >>>>> HV_X64_MSR_TIME_REF_COUNT, > >>>>> HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN, > >>>>> MSR_KVM_STEAL_TIME, > >>>>> MSR_KVM_PV_EOI_EN, > >>>>> MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, > >>>>> MSR_IA32_SYSENTER_EIP, > >>>>> @@ -1826,6 +1826,8 @@ static bool kvm_hv_msr_partition_wide(u32 msr) > >>>>> switch (msr) { > >>>>> case HV_X64_MSR_GUEST_OS_ID: > >>>>> case HV_X64_MSR_HYPERCALL: > >>>>> + case HV_X64_MSR_REFERENCE_TSC: > >>>>> + case HV_X64_MSR_TIME_REF_COUNT: > >>>>> r = true; > >>>>> break; > >>>>> } > >>>>> @@ -1865,6 +1867,29 @@ static int set_msr_hyperv_pw(struct kvm_vcpu > >>>>> *vcpu, u32 msr, u64 data) > >>>>> if (__copy_to_user((void __user *)addr, instructions, > >>>>> 4)) > >>>>> return 1; > >>>>> kvm->arch.hv_hypercall = data; > >>>>> + local_irq_disable(); > >>>>> + kvm->arch.hv_ref_count = get_kernel_ns() + > >>>>> kvm->arch.kvmclock_offset; > >>>>> + local_irq_enable(); > >>>> > >>>> Where does the docs say that HV_X64_MSR_HYPERCALL is the where the clock > >>>> starts counting? > >>>> > >>>> No need to store kvmclock_offset in hv_ref_count? (moreover > >>>> the name is weird, better name would be "hv_ref_start_time". > >>> > >>> Just add kvmclock_offset when reading the values (otherwise you have a > >>> "stale copy" of kvmclock_offset in hv_ref_count). > >>> > >> > >> After some experiments I think we do no need kvm->arch.hv_ref_count at all. > >> > >> I was debugging some weird clockjump issues and I think the problem is > >> that after live migration > >> kvm->arch.hv_ref_count is initialized to 0. Depending on the uptime of the > >> vServer when the > >> hypercall was set up this can lead to series jumps. > >> > >> So I would suggest to completely drop kvm->arch.hv_ref_count. > >> > >> And use simply this in get_msr_hyperv_pw(). > >> > >> case HV_X64_MSR_TIME_REF_COUNT: { > >> data = div_u64(get_kernel_ns() + > >> kvm->arch.kvmclock_offset, 100); > >> break; > >> } > >> > > > > Agreed. It should work as long as we rely on kvmclock_offset. > > Vadim. > > I think we can rely on kvmclock_offset. Had you had a chance to do further > testing > during the weekend?
Yes, and still testing. There is still some inconsistency in the value returned by QueryPerformanceCounter during migration. Vadim. > > Peter > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html