linux-kernel - Re: [PATCH 12/43] KVM: nVMX: Add helpers to identify shadowed VMCS fields

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Date:   Fri, 14 Jun 2019 09:10:54 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        vkuznets@...hat.com
Subject: Re: [PATCH 12/43] KVM: nVMX: Add helpers to identify shadowed VMCS
 fields

On Thu, Jun 13, 2019 at 07:02:58PM +0200, Paolo Bonzini wrote:
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index fc2b8f4cf45f..a6fe6cfe96f6 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -4503,41 +4526,27 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu)
>  	vmcs12_write_any(vmcs12, field, offset, field_value);
>  
>  	/*
> -	 * Do not track vmcs12 dirty-state if in guest-mode
> -	 * as we actually dirty shadow vmcs12 instead of vmcs12.
> +	 * Do not track vmcs12 dirty-state if in guest-mode as we actually
> +	 * dirty shadow vmcs12 instead of vmcs12.  Fields that can be updated
> +	 * by L1 without a vmexit are always updated in the vmcs02, i.e' don't

Minor typo (from my original patch), should be "i.e.", not "i.e'".

> +	 * "dirty" vmcs12, all others go down the prepare_vmcs02() slow path.
>  	 */
> -	if (!is_guest_mode(vcpu)) {
> -		switch (field) {