linux-kernel - Re: [PATCH kernel v5 5/6] KVM: SEV: Enable data breakpoints in SEV-ES

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Message-ID: <bdd24f91-16a4-a258-81ff-8ffd5a0a7623@amd.com>
Date:   Wed, 10 May 2023 11:35:15 +0200
From:   "Gupta, Pankaj" <pankaj.gupta@....com>
To:     Alexey Kardashevskiy <aik@....com>, kvm@...r.kernel.org
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org,
        Tom Lendacky <thomas.lendacky@....com>,
        Sean Christopherson <seanjc@...gle.com>,
        Nikunj A Dadhania <nikunj@....com>,
        Santosh Shukla <santosh.shukla@....com>,
        Carlos Bilbao <carlos.bilbao@....com>
Subject: Re: [PATCH kernel v5 5/6] KVM: SEV: Enable data breakpoints in SEV-ES


>> Enable DebugSwap for a VMSA but only do so if CPUID Fn80000021_EAX[0]
>> ("NoNestedDataBp", "Processor ignores nested data breakpoints") is
>> supported by the SOC as otherwise a malicious SEV-ES guest can set up
>> data breakpoints on the #DB IDT entry/stack and cause an infinite loop.
> 
> You mean #DB => #BP here
Indeed its #DB. Was thinking something else.

Reviewed-by: Pankaj Gupta <pankaj.gupta@....com>