linux-kernel - Re: [RFC PATCH v5 085/104] KVM: TDX: handle EXIT_REASON_OTHER

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Message-ID: <fdd40873-4a36-18c4-9e86-4601ee234d07@redhat.com>
Date:   Fri, 15 Apr 2022 16:29:56 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     isaku.yamahata@...el.com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     isaku.yamahata@...il.com, Jim Mattson <jmattson@...gle.com>,
        erdemaktas@...gle.com, Connor Kuehl <ckuehl@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>
Subject: Re: [RFC PATCH v5 085/104] KVM: TDX: handle EXIT_REASON_OTHER_SMI

On 3/4/22 20:49, isaku.yamahata@...el.com wrote:
> From: Isaku Yamahata <isaku.yamahata@...el.com>
> 
> If the control reaches EXIT_REASON_OTHER_SMI, #SMI is delivered and
> handled right after returning from the TDX module to KVM nothing needs to
> be done in KVM.  Continue TDX vcpu execution.
> 
> Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
> ---
>   arch/x86/include/uapi/asm/vmx.h | 1 +
>   arch/x86/kvm/vmx/tdx.c          | 7 +++++++
>   2 files changed, 8 insertions(+)
> 
> diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h
> index 946d761adbd3..3d9b4598e166 100644
> --- a/arch/x86/include/uapi/asm/vmx.h
> +++ b/arch/x86/include/uapi/asm/vmx.h
> @@ -34,6 +34,7 @@
>   #define EXIT_REASON_TRIPLE_FAULT        2
>   #define EXIT_REASON_INIT_SIGNAL			3
>   #define EXIT_REASON_SIPI_SIGNAL         4
> +#define EXIT_REASON_OTHER_SMI           6
>   
>   #define EXIT_REASON_INTERRUPT_WINDOW    7
>   #define EXIT_REASON_NMI_WINDOW          8
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index 155208a8d768..6fbe89bcfe1e 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -1097,6 +1097,13 @@ int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)
>   	WARN_ON_ONCE(fastpath != EXIT_FASTPATH_NONE);
>   
>   	switch (exit_reason.basic) {
> +	case EXIT_REASON_OTHER_SMI:
> +		/*
> +		 * If reach here, it's not a MSMI.

Please expand MSMI.  Otherwise,

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

Paolo

> +		 * #SMI is delivered and handled right after SEAMRET, nothing
> +		 * needs to be done in KVM.
> +		 */
> +		return 1;
>   	default:
>   		break;
>   	}