Re: [RFC PATCH 1/2] Hyper-H reference counter

Paolo Bonzini
2013-05-16T13:45:02Z

Il 16/05/2013 11:28, Vadim Rozenfeld ha scritto:
> On Thu, 2013-05-16 at 12:21 +0300, Gleb Natapov wrote:
>> On Thu, May 16, 2013 at 07:13:41PM +1000, Vadim Rozenfeld wrote:
>>> On Thu, 2013-05-16 at 11:34 +0300, Gleb Natapov wrote:
>>>> On Mon, May 13, 2013 at 09:45:16PM +1000, Vadim Rozenfeld wrote:
>>>>> Signed-off: Peter Lieven <pl@dlh.net>
>>>>> Signed-off: Gleb Natapov <gleb@redhat.com>
>>>>> Signed-off: Vadim Rozenfeld <vrozenfe@redhat.com>
>>>>>
>>>>> The following patch allows to activate Hyper-V
>>>>> reference time counter
>>>>> ---
>>>>> arch/x86/include/asm/kvm_host.h | 2 ++
>>>>> arch/x86/include/uapi/asm/hyperv.h | 3 +++
>>>>> arch/x86/kvm/x86.c | 25 ++++++++++++++++++++++++-
>>>>> 3 files changed, 29 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
>>>>> index 3741c65..f0fee35 100644
>>>>> --- a/arch/x86/include/asm/kvm_host.h
>>>>> +++ b/arch/x86/include/asm/kvm_host.h
>>>>> @@ -575,6 +575,8 @@ 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 b80420b..9711819 100644
>>>>> --- a/arch/x86/include/uapi/asm/hyperv.h
>>>>> +++ b/arch/x86/include/uapi/asm/hyperv.h
>>>>> @@ -136,6 +136,9 @@
>>>>> /* MSR used to read the per-partition time reference counter */
>>>>> #define HV_X64_MSR_TIME_REF_COUNT 0x40000020
>>>>>
>>>>> +/* A partition's reference time stamp counter (TSC) page */
>>>>> +#define HV_X64_MSR_REFERENCE_TSC 0x40000021
>>>>> +
>>>>> /* Define the virtual APIC registers */
>>>>> #define HV_X64_MSR_EOI 0x40000070
>>>>> #define HV_X64_MSR_ICR 0x40000071
>>>>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>>>>> index 094b5d9..1a4036d 100644
>>>>> --- a/arch/x86/kvm/x86.c
>>>>> +++ b/arch/x86/kvm/x86.c
>>>>> @@ -843,7 +843,7 @@ 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,
>>>>> @@ -1764,6 +1764,8 @@ 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;
>>>>> }
>>>>> @@ -1803,6 +1805,21 @@ 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;
>>>>> + kvm->arch.hv_ref_count = get_kernel_ns();

Please rename to kvm->arch.hv_ref_count_base.

>>>>> + break;
>>>>> + }
>>>>> + case HV_X64_MSR_REFERENCE_TSC: {
>>>>> + u64 gfn;
>>>>> + unsigned long addr;
>>>>> + u32 tsc_ref;
>>>>> + gfn = data >> HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_SHIFT;
>>>> Shouldn't you check HV_X64_MSR_TSC_REFERENCE_ENABLE here?
>>>
>>> Yes, I have this check added in the second patch.
>>>
>> Move it here please.
> OK, will do it.

Or better, remove all the handling of HV_X64_MSR_REFERENCE_TSC from this
patch, and leave it all to the second.

Paolo

>>>>
>>>>> + addr = gfn_to_hva(kvm, gfn);
>>>>> + if (kvm_is_error_hva(addr))
>>>>> + return 1;
>>>>> + tsc_ref = 0;
>>>>> + if(__copy_to_user((void __user *)addr, &tsc_ref, sizeof(tsc_ref)))
>>>>> + return 1;
>>>>> + kvm->arch.hv_tsc_page = data;
>>>>> break;
>>>>> }
>>>>> default:
>>>>> @@ -2229,6 +2246,12 @@ static int get_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
>>>>> case HV_X64_MSR_HYPERCALL:
>>>>> data = kvm->arch.hv_hypercall;
>>>>> break;
>>>>> + case HV_X64_MSR_TIME_REF_COUNT:
>>>>> + data = div_u64(get_kernel_ns() - kvm->arch.hv_ref_count,100);
>>>>> + break;
>>>>> + case HV_X64_MSR_REFERENCE_TSC:
>>>>> + data = kvm->arch.hv_tsc_page;
>>>>> + break;
>>>>> default:
>>>>> vcpu_unimpl(vcpu, "Hyper-V unhandled rdmsr: 0x%x\n", msr);
>>>>> return 1;
>>>>> --
>>>>> 1.8.1.2
>>>>
>>>> --
>>>> Gleb.
>>>
>>
>> --
>> Gleb.
>
>
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