linux-kernel - Re: [RFC PATCH v2 23/69] KVM: x86: Hoist kvm_dirty_regs check out of sync

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Date:   Tue, 6 Jul 2021 15:57:46 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     isaku.yamahata@...el.com, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, erdemaktas@...gle.com,
        Connor Kuehl <ckuehl@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     isaku.yamahata@...il.com,
        Sean Christopherson <sean.j.christopherson@...el.com>
Subject: Re: [RFC PATCH v2 23/69] KVM: x86: Hoist kvm_dirty_regs check out of
 sync_regs()

On 03/07/21 00:04, isaku.yamahata@...el.com wrote:
> From: Sean Christopherson <sean.j.christopherson@...el.com>
> 
> Move the kvm_dirty_regs vs. KVM_SYNC_X86_VALID_FIELDS check out of
> sync_regs() and into its sole caller, kvm_arch_vcpu_ioctl_run().  This
> allows a future patch to allow synchronizing select state for protected
> VMs.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
> ---
>   arch/x86/kvm/x86.c | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index d7110d48cbc1..271245ffc67c 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -9729,7 +9729,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>   		goto out;
>   	}
>   
> -	if (kvm_run->kvm_valid_regs & ~KVM_SYNC_X86_VALID_FIELDS) {
> +	if ((kvm_run->kvm_valid_regs & ~KVM_SYNC_X86_VALID_FIELDS) ||
> +	    (kvm_run->kvm_dirty_regs & ~KVM_SYNC_X86_VALID_FIELDS)) {
>   		r = -EINVAL;
>   		goto out;
>   	}
> @@ -10264,9 +10265,6 @@ static void store_regs(struct kvm_vcpu *vcpu)
>   
>   static int sync_regs(struct kvm_vcpu *vcpu)
>   {
> -	if (vcpu->run->kvm_dirty_regs & ~KVM_SYNC_X86_VALID_FIELDS)
> -		return -EINVAL;
> -
>   	if (vcpu->run->kvm_dirty_regs & KVM_SYNC_X86_REGS) {
>   		__set_regs(vcpu, &vcpu->run->s.regs.regs);
>   		vcpu->run->kvm_dirty_regs &= ~KVM_SYNC_X86_REGS;
> 

Reviewed-by: Paolo Bonzini <pbonzini@...hat.com>