Messages in this thread | | | Date | Tue, 10 Jan 2023 13:05:33 -0800 | Subject | Re: [PATCH 2/7] x86: Add CONFIG option X86_LASS | From | Sohil Mehta <> |
| |
The subject can be better stated as:
x86/Kconfig: Add config option for LASS
On 1/9/2023 9:51 PM, Yian Chen wrote: > LASS is an Intel x86-64 only feature.
> Add CONFIG > option X86_LASS and flag DISABLE_LASS to choose > opt-in/out the feature from kernel binary. > The second sentence is unnecessary.
> CONFIG_X86_LASS is enabled by default because it > is a security feature which should have little > to no overhead or side effects.
Doesn't it have a side effect that it modifies default vsyscall behavior?
I am guessing the impact of the vsyscall change would be minimal. However, should LASS be disabled by default at least initially to minimize the impact on userspace?
A follow-up patch can then enable this by default once the overall impact is clearly known.
> If any issues are > found with specific use cases, the CONFIG option > makes it easy to disable. >This sentence is unnecessary.
> > +config X86_LASS > + def_bool y > + prompt "Linear Address Space Separation" > + depends on X86_64 && CPU_SUP_INTEL > + help > + Linear Address Space Separation (LASS) is a processor > + feature that mitigates address space layout probes. > +
Let's try to be consistent about what LASS is expected to do. This definition is very different from the one in patch 1/7.
Also, we should include some information here on how enabling the LASS config option can impact vsyscall behavior.
> + if unsure, say Y. > +
| |