16 views
Skip to first unread message

yan yan

unread,
May 20, 2021, 7:40:23 AM5/20/21
to gvisor-users
Dear Friend:
My name is Yan Yan. Recently, i am learning the gVisor code, but i cannot unstandand the function about the "CheckHostCompatible()". It is to compare if the restored feature is  a subset of the host feature set. If i remove these part to check host feature, what will happen ?

yours sincerely,
Yan Yan

Michael Pratt

unread,
May 20, 2021, 10:38:13 AM5/20/21
to yan yan, gvisor-users
Many applications use CPUID at startup to determine which features are available and select from various implementations. e.g., using an AVX-optimized memcpy implementation when AVX is available. These decisions are usually cached to avoid using CPUID in the fast path.

If we save this application's state and restore it on a new machine with fewer features (e.g., no AVX support), then these applications are likely to crash with #UD / SIGILL when they try to use unsupported features.

--
You received this message because you are subscribed to the Google Groups "gVisor Users [Public]" group.
To unsubscribe from this group and stop receiving emails from it, send an email to gvisor-users...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/gvisor-users/CAES-NeYks4nBeCWjT%3DTPE20kKMnn1qGqRDo7OBe2aRC%3Dw9Dr5g%40mail.gmail.com.
Reply all
Reply to author
Forward
0 new messages