Handle Skylake-X errata SKZ63.
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Authored by kib on Apr 7 2018, 11:50 AM.

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alc
markj
emaste

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rS332182: Handle Skylake-X errata SKZ63.

Summary

SKZ63     Processor May Hang When Executing Code In an HLE Transaction Region

Problem:  Under certain conditions, if the processor acquires an HLE (Hardware Lock Elision) lock via the XACQUIRE instruction in the Host Physical Address range between 40000000H  and 403FFFFFH, it may hang with an internal timeout error (MCACOD 0400H) logged into IA32_MCi_STATUS.

Implication: Due to this erratum, the processor may hang after acquiring a lock via XACQUIRE.

Workaround: BIOS can reserve the host physical address ranges of 40000000H and 403FFFFFH (e.g. map it as UC/MMIO). Alternatively, the VMM (Virtual Machine Monitor) can reserve that address range so no guest can use it. In non-virtualized systems, the OS can reserve that memory space.

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rS FreeBSD src repository - subversion

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Event Timeline

kib created this revision.Apr 7 2018, 11:50 AM

Herald added a subscriber: imp. · View Herald TranscriptApr 7 2018, 11:50 AM

Harbormaster completed remote builds in B16037: Diff 41227.Apr 7 2018, 11:50 AM

kib edited the summary of this revision. (Show Details)Apr 7 2018, 11:51 AM

kib edited the summary of this revision. (Show Details)

kib added reviewers: alc, markj, emaste.Apr 7 2018, 11:53 AM

markj accepted this revision.Apr 7 2018, 3:36 PM

markj added inline comments.

sys/amd64/amd64/pmap.c
1295 ↗	(On Diff #41227)	Missing a period.
sys/vm/vm_page.h
479 ↗	(On Diff #41227)	Why boolean_t? bootverbose is an int and this header already uses bool.

This revision is now accepted and ready to land.Apr 7 2018, 3:36 PM

kib marked an inline comment as done.Apr 7 2018, 3:51 PM

kib added inline comments.

sys/vm/vm_page.h
479 ↗	(On Diff #41227)	vm_phys_unfree_page() returns int, I tried to be slightly more consistent with the internal interfaces. Changed both arg and result to bool.