Date: Wed, 16 Jan 2019 20:46:17 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 235010] bhyve: Linux guest crash due to unhandled MSR Message-ID: <bug-235010-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D235010 Bug ID: 235010 Summary: bhyve: Linux guest crash due to unhandled MSR Product: Base System Version: 12.0-RELEASE Hardware: amd64 OS: Any Status: New Keywords: bhyve Severity: Affects Some People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: rys@sommefeldt.com Created attachment 201198 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D201198&action= =3Dedit Bad boot due to unhandled Spectre v2 MSR bhyve in FreeBSD 12.0-RELEASE can't run certain Linux guests on certain AMD processors due to an unhandled MSR related to the Spectre v2 mitigation pre= sent in modern Linux kernels. Use of the -w switch lets at least certain guests run properly. The MSR is 0x49, and the bhyve log shows the guest attempting to set it to = 0x1. I've attached logs from a single vCPU configuration attempting to run Debian 9.6.0. debian9-1vCPU.log is from a run without -w debian9-1vCPU-ignore-unimplemented-msr.log is from a run with -w This LKML thread has more information on how it relates to Spectre v2 mitigation: https://lkml.org/lkml/2019/1/3/540 I don't understand the interaction between the Linux kernel and the CPU as presented to the guest by bhyve, with regards to the microcode. It's possib= le my host system needs a microcode update delivered by the BIOS or FreeBSD somehow, but I'm out of my depth there. I'm able to get guests that support the Linux kernel's spectre_v2_user=3Doff kernel boot param to boot OK, without needing -w. Let me know if I can do more testing. I'm running an AMD Ryzen Threadripper 2990WX with AGESA firmware 1.1.0.1a as part of the BIOS. --=20 You are receiving this mail because: You are the assignee for the bug.=
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