Date: Thu, 11 Feb 2010 17:00:13 +0200 From: Andriy Gapon <avg@icyb.net.ua> To: alc@freebsd.org Cc: freebsd-stable@freebsd.org, Ivan Voras <ivoras@freebsd.org>, Jeremy Chadwick <freebsd@jdc.parodius.com> Subject: Re: Strange problem with 8-stable, VMWare vSphere 4 & AMD CPUs (unexpected shutdowns) Message-ID: <4B741B7D.1030306@icyb.net.ua> In-Reply-To: <ca3526251002102037j21b11a7an572f397a9ae1eda0@mail.gmail.com> References: <hkujop$hsa$1@ger.gmane.org> <4B72D94A.8030509@icyb.net.ua> <hkup1g$763$1@ger.gmane.org> <4B72E93C.80102@icyb.net.ua> <9bbcef731002101003r203f5189xf139700a0d48afa0@mail.gmail.com> <4B72F67F.4000209@icyb.net.ua> <9bbcef731002101026k5007075cqf97fc80404ac3fa7@mail.gmail.com> <4B72FC55.2090508@icyb.net.ua> <9bbcef731002101038r1ac04141t505216816489376f@mail.gmail.com> <20100210184623.GA78851@icarus.home.lan> <ca3526251002102037j21b11a7an572f397a9ae1eda0@mail.gmail.com>
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on 11/02/2010 06:37 Alan Cox said the following: > Here is what I know. Several of us, myself included, have been able to > reproduce either lockups or machine check exceptions when BOTH the machine > check driver and superpages are enabled on AMD family 10h processors. There > have been no reports of this problem on either Intel or earlier AMD > processors. Moreover, there is no evidence of instability in AMD family 10h > processors until the machine check driver is enabled. By default, FreeBSD > 8.0 enables superpages but disables the machine check driver. So, running > natively, i.e., without virtualization, you shouldn't experience a problem, > unless you explicitly enable the machine check driver. However, running on > top of a hypervisor, like vSphere 4, you might face a problem because the > hypervisor might enable machine check exceptions, regardless of what the > FreeBSD guest does. I really don't know whether vSphere 4 enables machine > check exception or not. If it does, then either you disable the use of > superpages in the FreeBSD guest, or you find a way to disable the machine > check driver in the hypervisor. I'd like to mention another possibility, just in case: machine check might be enabled/done by firmware (e.g. BIOS). This typically could be the case for high-end-ish/server systems. -- Andriy Gapon
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