linux-kernel - Re: [Part2 PATCH v9 00/38] x86: Secure Encrypted Virtualization (AMD)

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Date:   Thu, 21 Dec 2017 10:09:44 -0600
From:   Brijesh Singh <brijesh.singh@....com>
To:     Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, x86@...nel.org
Cc:     brijesh.singh@....com, bp@...en8.de,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Radim KrÄmÃ¡Å™ 
        <rkrcmar@...hat.com>, Joerg Roedel <joro@...tes.org>,
        Borislav Petkov <bp@...e.de>,
        Tom Lendacky <thomas.lendacky@....com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S . Miller" <davem@...emloft.net>,
        Gary Hook <gary.hook@....com>, linux-crypto@...r.kernel.org
Subject: Re: [Part2 PATCH v9 00/38] x86: Secure Encrypted Virtualization (AMD)



On 12/21/17 9:51 AM, Brijesh Singh wrote:
>
> On 12/21/17 7:06 AM, Paolo Bonzini wrote:
> ....
>
> Hi Paolo,
>  
>
>> Hi Brijesh,
>>
>> I have a couple comments:
>>
>> 1) how is MSR_AMD64_SEV's value passed to the guest, and where is it in
>> the manual?
> It is a non interceptable read-only MSR set by the HW when SEV feature
> is enabled in VMRUN instruction.

I just checked both PPR and Family 17 manual and it seems both are still
missing this MSR definition. I will ping doc team to get it updated. thanks
>> 2) ECX should be 0 in the guest's 0x8000_001f leaf, because we don't
>> support nested SEV guests.  Likewise, EAX bit 2 should be 0 since you
>> don't emulate the page flush MSR.
> IIRC, I do clear both EAX Page_Flush and nested virtualization case from
> Qemu SEV feature is enabled.
>> Both can be fixed on top (and I can do the second myself of course), so
>> there should be no need for a v10.  
> Thanks
>