linux-kernel - Re: [PATCH 3/5 V2] tpm2: add longer timeouts for creation commands.

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Date:   Tue, 06 Mar 2018 14:23:25 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Tomas Winkler <tomas.winkler@...el.com>,
        Jason Gunthorpe <jgg@...pe.ca>
Cc:     Alexander Usyskin <alexander.usyskin@...el.com>,
        linux-integrity@...r.kernel.org,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/5 V2] tpm2: add longer timeouts for creation commands.

On Tue, 2018-03-06 at 11:25 +0200, Tomas Winkler wrote:
> TPM2_CC_Create(0x153) and TPM2_CC_CreatePrimary (0x131) involve generation
> of crypto keys which can be a computationally intensive task.
> The timeout is set to 3min.
> Rather than increasing default timeout a new constant is
> added, to not stall for too long on regular commands failures.
> 
> Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>

Why are you radically chaging the default timeout? The commit
message does not tell anything about that change.

Why couldn't we just have two timeouts: one default and one long that
would be at least as long as the longest timeout defined in the spec?
Then we would not have to ever update LAST_CC constant, we could
actually remove it completely.

/Jarkko