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 <[email protected]> >>>>> Signed-off: Gleb Natapov <[email protected]> >>>>> Signed-off: Vadim Rozenfeld <[email protected]> >>>>> >>>>> v1 -> v2 >>>>> 1. mark TSC page dirty as suggested by >>>>> Eric Northup <[email protected]> and Gleb >>>>> 2. disable local irq when calling get_kernel_ns, >>>>> as it was done by Peter Lieven <[email protected]> >>>>> 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? Peter -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
