Date: Wed, 11 Oct 2017 19:27:07 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 222937] [byhve] Severe RAM corruption after PciPassThrough-guest shutdown Message-ID: <bug-222937-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D222937 Bug ID: 222937 Summary: [byhve] Severe RAM corruption after PciPassThrough-guest shutdown Product: Base System Version: 11.1-STABLE Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: freebsd-bugs@FreeBSD.org Reporter: bugzilla.freebsd@omnilan.de Created attachment 187086 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D187086&action= =3Dedit /etc/rc.d/pciptdetach: Work around RAM corruption at guest shutdown Various different panics will happen after shutting down a bhyve guest with PCIe passthrough NICs if some conditions are met. This can lead to completely destroyed zpools, like I found out after some dozend not so impacting crashes... Quoting jhb@: I suspect what is happening is that the PCI devices are still issuing DMAs after the guest has been shutdown which end up trashing other parts of host memory. This may somewhat be my fault as I made a change which moves the device back into the host domain after FLR during guest shutdown. I should perhaps leave the device disabled in the DMAR table instead if the FLR doesn't succeed. (We could also add some other forms of reset for devices not supporting FLR.) </quote> Since I don't have the skills to help fixing the root cause, I wrote a litt= le workaround in form of a rc(8) script (to be copied to /etc/rc.d) which shou= ld protect against accidental crashes and data losses, by bringing the PciPassThrough devices down before shutting down, which prevents DMA writes from the card after moving it back into host domain. -harry --=20 You are receiving this mail because: You are the assignee for the bug.=
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