Messages in this thread | | | Date | Tue, 7 Apr 2020 17:24:12 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 3/4] x86,module: Detect VMX vs SLD conflicts |
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On Tue, Apr 07, 2020 at 04:35:43PM +0200, Greg KH wrote: > On Tue, Apr 07, 2020 at 01:02:39PM +0200, Peter Zijlstra wrote: > > It turns out that with Split-Lock-Detect enabled (default) any VMX > > hypervisor needs at least a little modification in order to not blindly > > inject the #AC into the guest without the guest being ready for it. > > > > Since there is no telling which module implements a hypervisor, scan > > all out-of-tree modules' text and look for VMX instructions and refuse > > to load it when SLD is enabled (default) and the module isn't marked > > 'sld_safe'. > > > > Hypervisors, which have been modified and are known to work correctly, > > can add: > > > > MODULE_INFO(sld_safe, "Y"); > > > > to explicitly tell the module loader they're good. > > What's to keep any out-of-tree module from adding this same module info > "flag" and just lie about it? Isn't that what you are trying to catch > here, or is it a case of, "if you lie, your code will break" as well?
If they lie they get to keep both pieces.
The thing I worry about is them lying about "intree", is there anything that avoids that?
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