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From: "Denis V. Lunev" <den@openvz.org>
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Date: Wed, 20 Jan 2016 17:44:49 +0300
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Subject: Re: [Qemu-devel] [PATCH v1] kvm/x86: Hyper-V tsc page setup
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To: Paolo Bonzini <pbonzini@redhat.com>, Andrey Smetanin <asmetanin@virtuozzo.com>, kvm@vger.kernel.org
Cc: Gleb Natapov <gleb@kernel.org>, Roman Kagan <rkagan@virtuozzo.com>, qemu-devel@nongnu.org

On 01/20/2016 05:05 PM, Paolo Bonzini wrote:
>
> On 19/01/2016 08:48, Denis V. Lunev wrote:
>>> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
>>> index 6877b4d7e..93c9e25 100644
>>> --- a/include/linux/kvm_host.h
>>> +++ b/include/linux/kvm_host.h
>>> @@ -145,6 +145,7 @@ static inline bool is_error_page(struct page *page)
>>>    #define KVM_REQ_HV_RESET          29
>>>    #define KVM_REQ_HV_EXIT           30
>>>    #define KVM_REQ_HV_STIMER         31
>>> +#define KVM_REQ_HV_TSC_PAGE       32
>>>      #define KVM_REQ_MAX               64
>>>    
>> ping
> Applied with this change:
>
> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> index d7716c6e2752..047c275717d3 100644
> --- a/arch/x86/kvm/hyperv.c
> +++ b/arch/x86/kvm/hyperv.c
> @@ -842,7 +842,7 @@ int kvm_hv_setup_tsc_page(struct kvm_vcpu *vcpu)
>   		   tsc_khz, tsc, tsc_scale, tsc_offset);
>   
>   	tsc_ref.tsc_sequence++;
> -	if (tsc_ref.tsc_sequence == 0)
> +	if (tsc_ref.tsc_sequence == 0xFFFFFFFF tsc_ref.tsc_sequence == 0)
>   		tsc_ref.tsc_sequence = 1;
>   
>   	tsc_ref.tsc_scale = tsc_scale;
>
> and renumbering KVM_REQ_HV_TSC_PAGE from 32 to 31.
>
> Paolo
the latter does not seem to be correct to me.
MS spec has bug, see this thread:
    https://lkml.org/lkml/2015/11/2/655
and the change was Acked-by: K.Y.

Den