linux-kernel - Re: [PATCH 1/5] KVM: hyperv: define VP assist page helpers

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Date:   Thu, 14 Jun 2018 16:40:12 -0700 (PDT)
From:   Liran Alon <liran.alon@...cle.com>
To:     <vkuznets@...hat.com>
Cc:     <mmorsy@...hat.com>, <rkagan@...tuozzo.com>, <jmattson@...gle.com>,
        <Michael.H.Kelley@...rosoft.com>, <kys@...rosoft.com>,
        <rkrcmar@...hat.com>, <cavery@...hat.com>, <pbonzini@...hat.com>,
        <linux-kernel@...r.kernel.org>, <sthemmin@...rosoft.com>,
        <haiyangz@...rosoft.com>, <kvm@...r.kernel.org>
Subject: Re: [PATCH 1/5] KVM: hyperv: define VP assist page helpers


----- vkuznets@...hat.com wrote:

> From: Ladi Prosek <lprosek@...hat.com>
> 
> The state related to the VP assist page is still managed by the LAPIC
> code in the pv_eoi field.
> 
> Signed-off-by: Ladi Prosek <lprosek@...hat.com>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
> ---
>  arch/x86/kvm/hyperv.c | 23 +++++++++++++++++++++--
>  arch/x86/kvm/hyperv.h |  4 ++++
>  arch/x86/kvm/lapic.c  |  4 ++--
>  arch/x86/kvm/lapic.h  |  2 +-
>  arch/x86/kvm/x86.c    |  2 +-
>  5 files changed, 29 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> index 14e0d0ae4e0a..fdf659ca6167 100644
> --- a/arch/x86/kvm/hyperv.c
> +++ b/arch/x86/kvm/hyperv.c
> @@ -688,6 +688,24 @@ void kvm_hv_vcpu_uninit(struct kvm_vcpu *vcpu)
>  		stimer_cleanup(&hv_vcpu->stimer[i]);
>  }
>  
> +bool kvm_hv_assist_page_enabled(struct kvm_vcpu *vcpu)
> +{
> +	if (!(vcpu->arch.hyperv.hv_vapic &
> HV_X64_MSR_VP_ASSIST_PAGE_ENABLE))
> +		return false;
> +	return vcpu->arch.pv_eoi.msr_val & KVM_MSR_ENABLED;
> +}
> +EXPORT_SYMBOL_GPL(kvm_hv_assist_page_enabled);
> +
> +bool kvm_hv_get_assist_page(struct kvm_vcpu *vcpu,
> +			    struct hv_vp_assist_page *assist_page)
> +{
> +	if (!kvm_hv_assist_page_enabled(vcpu))
> +		return false;
> +	return !kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.pv_eoi.data,
> +				      assist_page, sizeof(*assist_page));
> +}
> +EXPORT_SYMBOL_GPL(kvm_hv_get_assist_page);
> +
>  static void stimer_prepare_msg(struct kvm_vcpu_hv_stimer *stimer)
>  {
>  	struct hv_message *msg = &stimer->msg;
> @@ -1048,7 +1066,7 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu,
> u32 msr, u64 data, bool host)
>  
>  		if (!(data & HV_X64_MSR_VP_ASSIST_PAGE_ENABLE)) {
>  			hv->hv_vapic = data;
> -			if (kvm_lapic_enable_pv_eoi(vcpu, 0))
> +			if (kvm_lapic_enable_pv_eoi(vcpu, 0, 0))
>  				return 1;
>  			break;
>  		}
> @@ -1061,7 +1079,8 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu,
> u32 msr, u64 data, bool host)
>  		hv->hv_vapic = data;
>  		kvm_vcpu_mark_page_dirty(vcpu, gfn);
>  		if (kvm_lapic_enable_pv_eoi(vcpu,
> -					    gfn_to_gpa(gfn) | KVM_MSR_ENABLED))
> +					    gfn_to_gpa(gfn) | KVM_MSR_ENABLED,
> +					    sizeof(struct hv_vp_assist_page)))
>  			return 1;
>  		break;
>  	}
> diff --git a/arch/x86/kvm/hyperv.h b/arch/x86/kvm/hyperv.h
> index 837465d69c6d..db825bb7efc7 100644
> --- a/arch/x86/kvm/hyperv.h
> +++ b/arch/x86/kvm/hyperv.h
> @@ -62,6 +62,10 @@ void kvm_hv_vcpu_init(struct kvm_vcpu *vcpu);
>  void kvm_hv_vcpu_postcreate(struct kvm_vcpu *vcpu);
>  void kvm_hv_vcpu_uninit(struct kvm_vcpu *vcpu);
>  
> +bool kvm_hv_assist_page_enabled(struct kvm_vcpu *vcpu);
> +bool kvm_hv_get_assist_page(struct kvm_vcpu *vcpu,
> +			    struct hv_vp_assist_page *assist_page);
> +
>  static inline struct kvm_vcpu_hv_stimer *vcpu_to_stimer(struct
> kvm_vcpu *vcpu,
>  							int timer_index)
>  {
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index 776391cf69a5..b6d6a36f1a33 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -2540,7 +2540,7 @@ int kvm_hv_vapic_msr_read(struct kvm_vcpu *vcpu,
> u32 reg, u64 *data)
>  	return 0;
>  }
>  
> -int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data)
> +int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data, unsigned
> long len)
>  {
>  	u64 addr = data & ~KVM_MSR_ENABLED;
>  	if (!IS_ALIGNED(addr, 4))
> @@ -2550,7 +2550,7 @@ int kvm_lapic_enable_pv_eoi(struct kvm_vcpu
> *vcpu, u64 data)
>  	if (!pv_eoi_enabled(vcpu))
>  		return 0;
>  	return kvm_gfn_to_hva_cache_init(vcpu->kvm,
> &vcpu->arch.pv_eoi.data,
> -					 addr, sizeof(u8));
> +					 addr, len);
>  }
>  
>  void kvm_apic_accept_events(struct kvm_vcpu *vcpu)
> diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
> index ed0ed39abd36..ff6ef9c3d760 100644
> --- a/arch/x86/kvm/lapic.h
> +++ b/arch/x86/kvm/lapic.h
> @@ -120,7 +120,7 @@ static inline bool
> kvm_hv_vapic_assist_page_enabled(struct kvm_vcpu *vcpu)
>  	return vcpu->arch.hyperv.hv_vapic &
> HV_X64_MSR_VP_ASSIST_PAGE_ENABLE;
>  }
>  
> -int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data);
> +int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data, unsigned
> long len);
>  void kvm_lapic_init(void);
>  void kvm_lapic_exit(void);
>  
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 06dd4cdb2ca8..a57766b940a5 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -2442,7 +2442,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu,
> struct msr_data *msr_info)
>  
>  		break;
>  	case MSR_KVM_PV_EOI_EN:
> -		if (kvm_lapic_enable_pv_eoi(vcpu, data))
> +		if (kvm_lapic_enable_pv_eoi(vcpu, data, sizeof(u8)))
>  			return 1;
>  		break;
>  
> -- 
> 2.14.4

Reviewed-By: Liran Alon <liran.alon@...cle.com>