Messages in this thread | | | Date | Thu, 11 Mar 2021 21:32:06 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH v6 00/12] SVM cleanup and INVPCID feature support |
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On Thu, Mar 11, 2021 at 09:07:55PM +0100, Borislav Petkov wrote: > On Wed, Mar 10, 2021 at 07:21:23PM -0600, Babu Moger wrote: > > # git bisect good > > 59094faf3f618b2d2b2a45acb916437d611cede6 is the first bad commit > > commit 59094faf3f618b2d2b2a45acb916437d611cede6 > > Author: Borislav Petkov <bp@suse.de> > > Date: Mon Dec 25 13:57:16 2017 +0100 > > > > x86/kaiser: Move feature detection up > > What is the reproducer? > > Boot latest 4.9 stable kernel in a SEV guest? Can you send guest > .config? > > Upthread is talking about PCID, so I'm guessing host needs to be Zen3 > with PCID. Anything else?
That oops points to:
[ 1.237515] kernel BUG at /build/linux-dqnRSc/linux-4.9.228/arch/x86/kernel/alternative.c:709!
which is:
local_flush_tlb(); sync_core(); /* Could also do a CLFLUSH here to speed up CPU recovery; but that causes hangs on some VIA CPUs. */ for (i = 0; i < len; i++) BUG_ON(((char *)addr)[i] != ((char *)opcode)[i]); <--- local_irq_restore(flags); return addr;
in text_poke() which basically says that the patching verification fails. And you have a local_flush_tlb() before that. And with PCID maybe it is not flushing properly or whatnot.
And deep down in the TLB flushing code, it does:
if (kaiser_enabled) kaiser_flush_tlb_on_return_to_user();
and that uses PCID...
Anyway, needs more info.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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