Messages in this thread | | | Date | Fri, 3 Apr 2020 16:33:44 +0200 | From | Peter Zijlstra <> | Subject | Re: [patch v2 1/2] x86,module: Detect VMX modules and disable Split-Lock-Detect |
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On Fri, Apr 03, 2020 at 08:09:03AM +0000, David Laight wrote: > From: Peter Zijlstra > > Sent: 02 April 2020 16:24 > > > > I picked VMXOFF (which also appears in vmmon.ko) instead of VMXON > > because that latter takes an argument is therefore more difficult to > > decode. > ... > > + while (text < text_end) { > > + kernel_insn_init(&insn, text, text_end - text); > > + insn_get_length(&insn); > > + > > + if (WARN_ON_ONCE(!insn_complete(&insn))) > > + break; > > + > > + if (insn.length == 3 && > > + (!memcmp(text, vmlaunch, sizeof(vmlaunch)) || > > + !memcmp(text, vmxoff, sizeof(vmxoff)))) > > + goto bad_module; > > + > > + text += insn.length; > > + } > > How long is that going to take on a module with (say) 400k of text?
It's module load, why would you care? I suspect it's really fast, but even if it wasn't I couldn't be arsed.
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