Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 11 Jan 2023 18:49:39 -0800 | Subject | Re: [PATCH 4/7] x86/vsyscall: Setup vsyscall to compromise LASS protection | From | Sohil Mehta <> |
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>> The existing documentation here is incorrect. The default vsyscall >> mode is actually xonly. This has been so since: >> commit 625b7b7f79c6 (x86/vsyscall: Change the default vsyscall mode to >> xonly) >> > Yes, you are right. but this patch can overwrite and correct existing > one. I am assuming we don't need to correct the existing document first > before update it for LASS. >
We should fix this independent of the LASS enabling. I sent a patch earlier today to address it. I apologize, I missed cc'ing you.
https://lore.kernel.org/lkml/20230111193211.1987047-1-sohil.mehta@intel.com/
>>> + In newer versions of Intel platforms that come with >> >> Words such as "newer" in the kernel start losing meaning very quickly. >> Also, this comment looks out of place in between the vsyscall >> sub-options. >> >>> + LASS(Linear Address Space separation) protection, >>> + vsyscall is disabled by default. Enabling vsyscall >>> + via the parameter overrides LASS protection. >>> + > Sure, I will take out this part change.
Actually, having some text here might be ok. I mistook it to be placed between the sub-options. But avoid merging it with the previous paragraph as is the case right now.
>> Instead of doing this dance, can we provide a simplified behavior to >> the user/admin and move the decision making to compile time? >> > Current strategy is to disable vsyscall by default only for LASS capable > platforms. So that the dynamic decision is likely a necessary. >
Making this dynamic and platform dependent would make things hard to debug and isolate. It would be a perfect recipe for "But, it works on my system!" type of issues.
Let's see what others have to say.
-Sohil
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