From: Boris Petkov <bp@alien8.de>
To: Waiman Long <longman@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org
Cc: linux-kernel@vger.kernel.org,
Josh Poimboeuf <jpoimboe@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
Mark Gross <mgross@linux.intel.com>,
Tony Luck <tony.luck@intel.com>
Subject: Re: [PATCH v2 1/2] x86/speculation: Fix incorrect MDS/TAA mitigation status
Date: Fri, 15 Nov 2019 18:09:25 +0100 [thread overview]
Message-ID: <7EAED44C-A93E-405E-B57B-89AC3F779A70@alien8.de> (raw)
In-Reply-To: <20191115161445.30809-2-longman@redhat.com>
On November 15, 2019 5:14:44 PM GMT+01:00, Waiman Long <longman@redhat.com> wrote:
>For MDS vulnerable processors with TSX support, enabling either MDS or
>TAA mitigations will enable the use of VERW to flush internal processor
>buffers at the right code path. IOW, they are either both mitigated
>or both not. However, if the command line options are inconsistent,
>the vulnerabilites sysfs files may not report the mitigation status
>correctly.
>
>For example, with only the "mds=off" option:
>
> vulnerabilities/mds:Vulnerable; SMT vulnerable
>vulnerabilities/tsx_async_abort:Mitigation: Clear CPU buffers; SMT
>vulnerable
>
>The mds vulnerabilities file has wrong status in this case. Similarly,
>the taa vulnerability file will be wrong with mds mitigation on, but
>taa off.
>
>Change taa_select_mitigation() to sync up the two mitigation status
>and have them turned off if both "mds=off" and "tsx_async_abort=off"
>are present.
>
>Both hw-vuln/mds.rst and hw-vuln/tsx_async_abort.rst are updated
>to emphasize the fact that both "mds=off" and "tsx_async_abort=off"
>have to be specified together for processors that are affected by both
>TAA and MDS to be effective. As kernel-parameter.txt references both
>documents above, it is not necessary to update it.
What about kernel-parameters.txt?
--
Sent from a small device: formatting sux and brevity is inevitable.
next prev parent reply other threads:[~2019-11-15 17:09 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-15 16:14 [PATCH v2 0/2] x86/speculation: Fix incorrect MDS/TAA mitigation status Waiman Long
2019-11-15 16:14 ` [PATCH v2 1/2] " Waiman Long
2019-11-15 17:09 ` Boris Petkov [this message]
2019-11-15 19:35 ` Thomas Gleixner
2019-11-15 20:21 ` Boris Petkov
2019-11-18 1:17 ` Waiman Long
2019-11-16 12:25 ` [tip: x86/pti] " tip-bot2 for Waiman Long
2019-11-15 16:14 ` [PATCH v2 2/2] x86/speculation: Fix redundant MDS mitigation message Waiman Long
2019-11-16 12:25 ` [tip: x86/pti] " tip-bot2 for Waiman Long
2019-11-16 14:24 ` Borislav Petkov
2019-11-18 1:22 ` Waiman Long
2019-11-16 14:38 ` tip-bot2 for Waiman Long
2019-11-15 16:17 ` [PATCH v2 0/2] x86/speculation: Fix incorrect MDS/TAA mitigation status Waiman Long
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