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Sender: Paolo Bonzini <paolo.bonzini@gmail.com>
Message-ID: <5fd8d6dd-07be-9bf1-1ad9-5536c4e40182@redhat.com>
Date:   Fri, 15 Apr 2022 16:20:56 +0200
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Subject: Re: [RFC PATCH v5 071/104] KVM: TDX: restore debug store when TD exit
Content-Language: en-US
To:     isaku.yamahata@intel.com, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     isaku.yamahata@gmail.com, Jim Mattson <jmattson@google.com>,
        erdemaktas@google.com, Connor Kuehl <ckuehl@redhat.com>,
        Sean Christopherson <seanjc@google.com>
References: <cover.1646422845.git.isaku.yamahata@intel.com>
 <c7f81bd80af0f57ff2fabef24a218fb43c3d0e3c.1646422845.git.isaku.yamahata@intel.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
In-Reply-To: <c7f81bd80af0f57ff2fabef24a218fb43c3d0e3c.1646422845.git.isaku.yamahata@intel.com>
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On 3/4/22 20:49, isaku.yamahata@intel.com wrote:
> From: Isaku Yamahata <isaku.yamahata@intel.com>
> 
> Because debug store is clobbered, restore it on TD exit.
> 
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
>   arch/x86/events/intel/ds.c | 1 +
>   arch/x86/kvm/vmx/tdx.c     | 1 +
>   2 files changed, 2 insertions(+)
> 
> diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
> index 376cc3d66094..cdba4227ad3b 100644
> --- a/arch/x86/events/intel/ds.c
> +++ b/arch/x86/events/intel/ds.c
> @@ -2256,3 +2256,4 @@ void perf_restore_debug_store(void)
>   
>   	wrmsrl(MSR_IA32_DS_AREA, (unsigned long)ds);
>   }
> +EXPORT_SYMBOL_GPL(perf_restore_debug_store);
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index 3cb2fbd1c12c..37cf7d43435d 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -620,6 +620,7 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu)
>   	tdx_vcpu_enter_exit(vcpu, tdx);
>   
>   	tdx_user_return_update_cache();
> +	perf_restore_debug_store();
>   	tdx_restore_host_xsave_state(vcpu);
>   	tdx->host_state_need_restore = true;
>   

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