linux-kernel - Re: [RFC Part2 PATCH v3 03/26] crypto: ccp: Add Secure Encrypted Virtualization (SEV) device support

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Date:   Wed, 13 Sep 2017 10:18:52 -0500
From:   Brijesh Singh <brijesh.singh@....com>
To:     Borislav Petkov <bp@...e.de>
Cc:     brijesh.singh@....com, linux-kernel@...r.kernel.org,
        x86@...nel.org, kvm@...r.kernel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Joerg Roedel <joro@...tes.org>,
        "Michael S . Tsirkin" <mst@...hat.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        \"Radim Krčmář\" <rkrcmar@...hat.com>,
        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: [RFC Part2 PATCH v3 03/26] crypto: ccp: Add Secure Encrypted
 Virtualization (SEV) device support



On 09/13/2017 09:17 AM, Borislav Petkov wrote:
...

>> +
>> +unlock:
>> +	mutex_unlock(&sev_cmd_mutex);
>> +	print_hex_dump_debug("(out): ", DUMP_PREFIX_OFFSET, 16, 2, data,
>> +			sev_cmd_buffer_len(cmd), false);
>> +	return ret;
> 
> ... and here you return psp_ret == 0 even though something failed.
> 
> What I think you should do is not touch @psp_ret when you return before
> the SEV command executes and *when* you return, set @psp_ret accordingly
> to denote the status of the command execution.
> 
> Or if you're touching it before you execute the SEV
> command and you return early, it should say something like
> PSP_CMDRESP_COMMAND_DIDNT_EXECUTE or so, to tell the caller exactly what
> happened.
> 

Agreed, very good catch thank you. I will fix it.

-Brijesh