From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 856D21A9B24; Mon, 23 Mar 2026 05:26:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774243598; cv=none; b=J057AJlvvRy05obOXqFRjOgwHrADdmDyKgWrVXjkeLX9cegkl7O5DmgrmJzqGlpHIcJjvkb4TLWBUmz9m+Sav/ELRLFcxBuXD4IHGyAf0RBOOS9F4s8u94Ka3AQu7ZZCAhNXNfCsK/4BbqvK4tc0LG3007CmX7UvtuLRtMkVbjE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774243598; c=relaxed/simple; bh=Zux8o07G2J4eusOzTUquskkr9AqL7vPLoD/1LMsSxMU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sT5ztm63/wXrXy8Q/l/nJ2q5aLQF0GIhC31cpqZVKgNwdA3zzo9/wjQ30XXr+3odQVYbpHMEjNttPRrx5GbDtrlDq2tRGJZhOexcCEzbNG3VNfVl3El8p8Tt93ZnOds32InD9lsQ9zD3vuNmsy/Hk1ULPRn1gKm5UckJp50dfs0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eXQhfE6l; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eXQhfE6l" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5EE46C4CEF7; Mon, 23 Mar 2026 05:26:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774243598; bh=Zux8o07G2J4eusOzTUquskkr9AqL7vPLoD/1LMsSxMU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eXQhfE6l3BN343u1Z9aqxFvBWRH15kjpfLZNm4Hv241nP6SXlGnnzv6XMrszbAHJ8 39NFfLv/uy86fMgUSHhDUU5FTJNV8d4JVyV7gIBCc3pbGR/kL6OPbSgQsD8gLLlSP4 uSFD1ie0pOA8mK5HVcpnaFeagbv/WiBcfqx1QRzxys7brKbesekh4PbvjZ7xGsyezi V0U2Eri6Yv/Zs5QKyF9lRIk+AsAXNq83NAjRsUhMbPvym3Vb2BgJ1SjBfx0Lag4oYD BNkZBnxlz1LouK5tt1ScAhFRmBABcQ/3FeJaFBQlfkxMcGL7mffnP6SZHBjuIXfrNZ Q0z3qSunXmJMQ== Date: Mon, 23 Mar 2026 07:26:33 +0200 From: Jarkko Sakkinen To: Mimi Zohar Cc: Chris Fenner , linux-integrity@vger.kernel.org, Jonathan McDowell , Eric Biggers , James Bottomley , David Howells , Paul Moore , James Morris , "Serge E. Hallyn" , "open list:KEYS-TRUSTED" , "open list:SECURITY SUBSYSTEM" , open list , Roberto Sassu Subject: Re: [PATCH v9 01/11] KEYS: trusted: Use get_random-fallback for TPM Message-ID: References: <20260125192526.782202-1-jarkko@kernel.org> <20260125192526.782202-2-jarkko@kernel.org> <06a08cbbe47111a1795e5dcd42fb8cc4be643a72.camel@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Mar 19, 2026 at 10:28:03AM -0400, Mimi Zohar wrote: > On Wed, 2026-03-18 at 10:36 -0700, Chris Fenner wrote: > > Apologies if my long message derailed this discussion. I meant to > > support Mimi's concern here and project a future vision where > > TCG_TPM2_HMAC doesn't conflict with other features. > > > > More concisely, I think that: > > > > > tpm2_get_random() is costly when TCG_TPM2_HMAC is enabled > > > > is not a compelling argument for removing TPM as an RNG source, > > because TCG_TPM2_HMAC is known to have poor performance already > > anyway. > > Agreed. Thanks, Chris! FYI, we raised concerns about IMA performance with the > TPM HMAC and encrypted feature while it was being developed. James had some > ideas, at the time, as to how to resolve the performance issue for IMA. Yet it > was upstreamed without those changes and with CONFIG_TCG_TPM2_HMAC enabled by > default on x86 systems. > > Jarkko has queued this patch in the "queue" branch, without indicating whether > it will eventually be upstreamed or not. Yes and there's been multiple months of time to comment this and I backed up the patch set there, which is not same as applying it. > > Mimi BR, Jarkko