Messages in this thread | | | Date | Thu, 14 Nov 2019 19:48:39 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH] x86/speculation: Fix incorrect MDS/TAA mitigation status |
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On Thu, 14 Nov 2019, Waiman Long wrote: > On 11/14/19 12:45 PM, Borislav Petkov wrote: > >> - /* TAA mitigation is turned off on the cmdline (tsx_async_abort=off) */ > >> - if (taa_mitigation == TAA_MITIGATION_OFF) > >> + /* > >> + * TAA mitigation via VERW is turned off if both > >> + * tsx_async_abort=off and mds=off are specified. > >> + */ > > So this changes the dependency of switches so if anything, it should be > > properly documented first in all three: > > > > Documentation/admin-guide/hw-vuln/tsx_async_abort.rst > > Documentation/x86/tsx_async_abort.rst > > Documentation/admin-guide/kernel-parameters.txt > > > > However, before we do that, we need to agree on functionality: > I agree that the documentation needs to be updated. I am going to do > that once we have a consensus of what is the right thing to do. > > Will the mitigations be disabled only with *both* =off supplied on the > > command line or should the mitigations be disabled when *any* of the two > > =off is supplied? > > The mitigation is disabled only with BOTH =off supplied or > "mitigations=off". This is the current behavior. This patch is just to > make sure that vulnerabilities files reflect the actual behavior. Of > course, we can change it to disable mitigation with either =off if this > is what the consensus turn out to be.
I think the current behaviour is correct. It's just a coincidence that both issues happen to use the same mitigation technology in the exactly same places. So if you leave one on then the other gets mitigated as a side effect and the sysfs file should reflect that.
Thanks,
tglx
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