linux-kernel - Re: [PATCH v5 08/34] KVM: SVM: Prevent debugging under SEV-ES

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Message-ID: <e8ace428-af96-663e-7f78-dff898dfa722@amd.com>
Date:   Mon, 14 Dec 2020 13:10:06 -0600
From:   Tom Lendacky <thomas.lendacky@....com>
To:     Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, x86@...nel.org
Cc:     Jim Mattson <jmattson@...gle.com>, Joerg Roedel <joro@...tes.org>,
        Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Borislav Petkov <bp@...en8.de>, Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Brijesh Singh <brijesh.singh@....com>
Subject: Re: [PATCH v5 08/34] KVM: SVM: Prevent debugging under SEV-ES

On 12/14/20 9:41 AM, Paolo Bonzini wrote:
> On 10/12/20 18:09, Tom Lendacky wrote:
>> Additionally, an SEV-ES guest must only and always intercept DR7 reads and
>> writes. Update set_dr_intercepts() and clr_dr_intercepts() to account for
>> this.
> 
> I cannot see it, where is this documented?

That is documented in the GHCB specification, section 4.5 Debug Register
Support:

https://developer.amd.com/wp-content/resources/56421.pdf

Thanks,
Tom

> 
> Paolo
>