linux-kernel - Re: [PATCH 05/10] KVM: VMX: Convert local exit_reason to u16 in vmx_handle

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Message-ID: <87sgicnz6l.fsf@vitty.brq.redhat.com>
Date:   Fri, 13 Mar 2020 14:48:18 +0100
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     Sean Christopherson <sean.j.christopherson@...el.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Xiaoyao Li <xiaoyao.li@...el.com>
Subject: Re: [PATCH 05/10] KVM: VMX: Convert local exit_reason to u16 in vmx_handle_exit()

Sean Christopherson <sean.j.christopherson@...el.com> writes:

> Convert the local "exit_reason" in vmx_handle_exit() from a u32 to a u16
> as most references expect to encounter only the basic exit reason.  Use
> vmx->exit_reason directly for paths that expect the full exit reason,
> i.e. to avoid having to figure out a decent name for a second local
> variable.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
> ---
>  arch/x86/kvm/vmx/vmx.c | 17 ++++++++++-------
>  1 file changed, 10 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index c7715c880ea7..d43e1d28bb58 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -5844,10 +5844,10 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu,
>  	enum exit_fastpath_completion exit_fastpath)
>  {
>  	struct vcpu_vmx *vmx = to_vmx(vcpu);
> -	u32 exit_reason = vmx->exit_reason;
>  	u32 vectoring_info = vmx->idt_vectoring_info;
> +	u16 exit_reason;
>  
> -	trace_kvm_exit(exit_reason, vcpu, KVM_ISA_VMX);
> +	trace_kvm_exit(vmx->exit_reason, vcpu, KVM_ISA_VMX);
>  
>  	/*
>  	 * Flush logged GPAs PML buffer, this will make dirty_bitmap more
> @@ -5866,11 +5866,11 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu,
>  	if (is_guest_mode(vcpu) && nested_vmx_reflect_vmexit(vcpu))
>  		return 1;
>  
> -	if (exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY) {
> +	if (vmx->exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY) {
>  		dump_vmcs();
>  		vcpu->run->exit_reason = KVM_EXIT_FAIL_ENTRY;
>  		vcpu->run->fail_entry.hardware_entry_failure_reason
> -			= exit_reason;
> +			= vmx->exit_reason;
>  		return 0;
>  	}
>  
> @@ -5882,6 +5882,8 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu,
>  		return 0;
>  	}
>  
> +	exit_reason = vmx->exit_reason;
> +
>  	/*
>  	 * Note:
>  	 * Do not try to fix EXIT_REASON_EPT_MISCONFIG if it caused by
> @@ -5898,7 +5900,7 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu,
>  		vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_DELIVERY_EV;
>  		vcpu->run->internal.ndata = 3;
>  		vcpu->run->internal.data[0] = vectoring_info;
> -		vcpu->run->internal.data[1] = exit_reason;
> +		vcpu->run->internal.data[1] = vmx->exit_reason;
>  		vcpu->run->internal.data[2] = vcpu->arch.exit_qualification;
>  		if (exit_reason == EXIT_REASON_EPT_MISCONFIG) {
>  			vcpu->run->internal.ndata++;
> @@ -5957,13 +5959,14 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu,
>  	return kvm_vmx_exit_handlers[exit_reason](vcpu);
>  
>  unexpected_vmexit:
> -	vcpu_unimpl(vcpu, "vmx: unexpected exit reason 0x%x\n", exit_reason);
> +	vcpu_unimpl(vcpu, "vmx: unexpected exit reason 0x%x\n",
> +		    vmx->exit_reason);
>  	dump_vmcs();
>  	vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
>  	vcpu->run->internal.suberror =
>  			KVM_INTERNAL_ERROR_UNEXPECTED_EXIT_REASON;
>  	vcpu->run->internal.ndata = 1;
> -	vcpu->run->internal.data[0] = exit_reason;
> +	vcpu->run->internal.data[0] = vmx->exit_reason;
>  	return 0;
>  }

Reviewed-by: Vitaly Kuznetsov <vkuznets@...hat.com>

-- 
Vitaly