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Subject: Re: [PATCH] KVM: SVM: Mark SEV launch secret pages as dirty.
To:     Sean Christopherson <sean.j.christopherson@intel.com>
Cc:     Cfir Cohen <cfir@google.com>,
        "kvm @ vger . kernel . org" <kvm@vger.kernel.org>,
        Lendacky Thomas <thomas.lendacky@amd.com>,
        Singh Brijesh <brijesh.singh@amd.com>,
        Grimm Jon <Jon.Grimm@amd.com>,
        David Rientjes <rientjes@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H . Peter Anvin" <hpa@zytor.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org
References: <20200807012303.3769170-1-cfir@google.com>
 <20200919045505.GC21189@sjchrist-ice>
 <5ac77c46-88b4-df45-4f02-72adfb096262@redhat.com>
 <20200923170444.GA20076@linux.intel.com>
 <548b7b73-7a13-8267-414e-2b9e1569c7f7@redhat.com>
 <20200923172646.GB32044@linux.intel.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <0ccf42d8-2803-c1db-73f0-884d1ea27282@redhat.com>
Date:   Wed, 23 Sep 2020 19:27:37 +0200
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On 23/09/20 19:26, Sean Christopherson wrote:
> 	/*
> 	 * Flush before LAUNCH_UPDATE encrypts pages in place, in case the cache
> 	 * contains the data that was written unencrypted.
>  	 */
>  	sev_clflush_pages(inpages, npages);
> 
> there's nothing in the comment or code that even suggests sev_clflush_pages() is
> conditional, i.e. no reason for the reader to peek at the implemenation.
> 
> What about:
> 
> 	/*
> 	 * Flush (on non-coherent CPUs) before LAUNCH_UPDATE encrypts pages in
> 	 * place, the cache may contain data that was written unencrypted.
> 	 */

Sounds good.

Paolo