linux-kernel - Re: [Part2 PATCH v6 13/38] crypto: ccp: Add Secure Encrypted Virtualization (SEV) command support

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Date:   Fri, 27 Oct 2017 15:25:24 -0500
From:   Brijesh Singh <brijesh.singh@....com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     brijesh.singh@....com, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        Gary Hook <gary.hook@....com>,
        Tom Lendacky <thomas.lendacky@....com>,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [Part2 PATCH v6 13/38] crypto: ccp: Add Secure Encrypted
 Virtualization (SEV) command support



On 10/27/17 3:15 PM, Borislav Petkov wrote:
> On Fri, Oct 27, 2017 at 06:28:38AM -0500, Brijesh Singh wrote:
>> ... User can retry the command sometime later when nobody else is
>> using the PSP.
> That still doesn't prevent you from doing two things:
>
> * make that fw_init_count a proper kref instead of your homegrown thing

OK, I can use kref in next patch.

>
> * do not preemptively execute commands on the PSP if you can't possibly
> know what the next command is going to be - instead, just put it in the
> required state only when you really have to. I.e., don't do all that
> unnecessary INIT -> CMD -> SHUTDOWN game for no reason.

Yep, we are doing state transition only when we really need to. At least
so far I have tried to avoid making any unnecessary state transitions.

> Thx.
>