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From: Paolo Bonzini <pbonzini@redhat.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>, kvm@vger.kernel.org
Cc: Sean Christopherson <seanjc@google.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>,
	Maxim Levitsky <mlevitsk@redhat.com>,
	Vineeth Pillai <viremana@linux.microsoft.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/5] KVM: SVM: Drop stale comment from svm_hv_vmcb_dirty_nested_enlightenments()
Date: Tue, 25 Jan 2022 16:57:05 +0100	[thread overview]
Message-ID: <21da89ed-fe72-f824-902c-a7c4999a908e@redhat.com> (raw)
In-Reply-To: <20211220152139.418372-2-vkuznets@redhat.com>

On 12/20/21 16:21, Vitaly Kuznetsov wrote:
> Commit 3fa5e8fd0a0e4 ("KVM: SVM: delay svm_vcpu_init_msrpm after
> svm->vmcb is initialized") re-arranged svm_vcpu_init_msrpm() call in
> svm_create_vcpu() making the comment about vmcb being NULL
> obsolete. Drop it.
> 
> While on it, drop superfluous vmcb_is_clean() check: vmcb_mark_dirty()
> is a bit flip, an extra check is unlikely to bring any performance gain.
> Drop now-unneeded vmcb_is_clean() helper as well.
> 
> Fixes: 3fa5e8fd0a0e4 ("KVM: SVM: delay svm_vcpu_init_msrpm after svm->vmcb is initialized")
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>

Queued, but with subject changed to "KVM: SVM: clean up beginning of 
svm_hv_vmcb_dirty_nested_enlightenments()".

Paolo

>   arch/x86/kvm/svm/svm.h          | 5 -----
>   arch/x86/kvm/svm/svm_onhyperv.h | 9 +--------
>   2 files changed, 1 insertion(+), 13 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
> index daa8ca84afcc..5d197aae3a19 100644
> --- a/arch/x86/kvm/svm/svm.h
> +++ b/arch/x86/kvm/svm/svm.h
> @@ -305,11 +305,6 @@ static inline void vmcb_mark_all_clean(struct vmcb *vmcb)
>   			       & ~VMCB_ALWAYS_DIRTY_MASK;
>   }
>   
> -static inline bool vmcb_is_clean(struct vmcb *vmcb, int bit)
> -{
> -	return (vmcb->control.clean & (1 << bit));
> -}
> -
>   static inline void vmcb_mark_dirty(struct vmcb *vmcb, int bit)
>   {
>   	vmcb->control.clean &= ~(1 << bit);
> diff --git a/arch/x86/kvm/svm/svm_onhyperv.h b/arch/x86/kvm/svm/svm_onhyperv.h
> index c53b8bf8d013..cdbcfc63d171 100644
> --- a/arch/x86/kvm/svm/svm_onhyperv.h
> +++ b/arch/x86/kvm/svm/svm_onhyperv.h
> @@ -83,14 +83,7 @@ static inline void svm_hv_vmcb_dirty_nested_enlightenments(
>   	struct hv_enlightenments *hve =
>   		(struct hv_enlightenments *)vmcb->control.reserved_sw;
>   
> -	/*
> -	 * vmcb can be NULL if called during early vcpu init.
> -	 * And its okay not to mark vmcb dirty during vcpu init
> -	 * as we mark it dirty unconditionally towards end of vcpu
> -	 * init phase.
> -	 */
> -	if (vmcb_is_clean(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS) &&
> -	    hve->hv_enlightenments_control.msr_bitmap)
> +	if (hve->hv_enlightenments_control.msr_bitmap)
>   		vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
>   }
>   


  reply	other threads:[~2022-01-25 15:59 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-20 15:21 [PATCH 0/5] KVM: SVM: nSVM: Implement Enlightened MSR-Bitmap for Hyper-V-on-KVM and fix it for KVM-on-Hyper-V Vitaly Kuznetsov
2021-12-20 15:21 ` [PATCH 1/5] KVM: SVM: Drop stale comment from svm_hv_vmcb_dirty_nested_enlightenments() Vitaly Kuznetsov
2022-01-25 15:57   ` Paolo Bonzini [this message]
2021-12-20 15:21 ` [PATCH 2/5] KVM: SVM: hyper-v: Enable Enlightened MSR-Bitmap support for real Vitaly Kuznetsov
2022-01-25 15:53   ` Paolo Bonzini
2021-12-20 15:21 ` [PATCH 3/5] KVM: nSVM: Track whether changes in L0 require MSR bitmap for L2 to be rebuilt Vitaly Kuznetsov
2021-12-20 15:21 ` [PATCH 4/5] KVM: x86: Make kvm_hv_hypercall_enabled() static inline Vitaly Kuznetsov
2021-12-20 15:21 ` [PATCH 5/5] KVM: nSVM: Implement Enlightened MSR-Bitmap feature Vitaly Kuznetsov
2022-02-01 13:49 ` [PATCH 0/5] KVM: SVM: nSVM: Implement Enlightened MSR-Bitmap for Hyper-V-on-KVM and fix it for KVM-on-Hyper-V Paolo Bonzini
2022-02-01 14:31   ` Vitaly Kuznetsov
2022-02-01 18:30     ` Paolo Bonzini
2022-02-01 18:58       ` Vitaly Kuznetsov
2022-02-01 19:22         ` Paolo Bonzini
2022-02-02  9:52           ` Vitaly Kuznetsov

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