linux-kernel - Re: [PATCH] KVM: VMX: Fix and tweak the comments for VM-Enter

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Message-ID: <aa33f0e1-e999-08b0-8826-0b88f4681561@redhat.com>
Date:   Mon, 19 Aug 2019 17:47:33 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Radim Krčmář <rkrcmar@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KVM: VMX: Fix and tweak the comments for VM-Enter

On 15/08/19 22:09, Sean Christopherson wrote:
> Fix an incorrect/stale comment regarding the vmx_vcpu pointer, as guest
> registers are now loaded using a direct pointer to the start of the
> register array.
> 
> Opportunistically add a comment to document why the vmx_vcpu pointer is
> needed, its consumption via 'call vmx_update_host_rsp' is rather subtle.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
> ---
>  arch/x86/kvm/vmx/vmenter.S | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S
> index 4010d519eb8c..751a384c2eb0 100644
> --- a/arch/x86/kvm/vmx/vmenter.S
> +++ b/arch/x86/kvm/vmx/vmenter.S
> @@ -94,7 +94,7 @@ ENDPROC(vmx_vmexit)
>  
>  /**
>   * __vmx_vcpu_run - Run a vCPU via a transition to VMX guest mode
> - * @vmx:	struct vcpu_vmx *
> + * @vmx:	struct vcpu_vmx * (forwarded to vmx_update_host_rsp)
>   * @regs:	unsigned long * (to guest registers)
>   * @launched:	%true if the VMCS has been launched
>   *
> @@ -151,7 +151,7 @@ ENTRY(__vmx_vcpu_run)
>  	mov VCPU_R14(%_ASM_AX), %r14
>  	mov VCPU_R15(%_ASM_AX), %r15
>  #endif
> -	/* Load guest RAX.  This kills the vmx_vcpu pointer! */
> +	/* Load guest RAX.  This kills the @regs pointer! */
>  	mov VCPU_RAX(%_ASM_AX), %_ASM_AX
>  
>  	/* Enter guest mode */
> 

Queued, thanks.

Paolo