Messages in this thread | | | Subject | Re: Linux FSGSBASE testing | From | Don Porter <> | Date | Sat, 18 Jul 2020 16:18:06 -0400 |
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On 6/20/20 11:59 AM, Andy Lutomirski wrote: > Hi Stas- > > FSGSBASE support is queued up for Linux 5.9. Since you're one of the > more exotic users of segmentation on Linux, is there any chance you > could test it? The code is here: > > https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/log/?h=x86/fsgsbase > > There are two interesting cases to test: > > 1. FSGSBASE on. This is the default if you boot this kernel on Ivy > Bridge or newer hardware. > > 2. FSGSBASE off on a patched kernel. Boot the same kernel as in #1 > but either pass nofsgsbase on the kernel command line or use pre-Ivy > Bridge hardware. You will * > > You can tell you have FSGSBASE enabled for test #1 by running > tools/testing/selftests/x86/fsgsbase_64 -- the first line of output > will be :FSGSBASE instructions are enabled". You can build it by > cd-ing to tools/testing/selftests/x86 and running make. > > If anything is broken for you, I'd like to know before this makes it > into a released kernel! > > Thanks, > Andy >
FWIW, we tested this patch using Graphene under Case 1, both in our standard CI pipelines, and with hand testing. Everything looks good on our end - no suspicious dmesg, no application-level issues.
I also reran the stress test Andy suggested on a separate thread, which also looks good: * Graphene running nginx pinned to core 0 * infinite loop on core 0 * perf top running * Exercised with non-SGX apache bench several times (~10 minutes of testing time) also from core 0
All the best, Don
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