On 2014-04-03 09:08, Frank Leonhardt wrote: > On 03/04/2014 12:36, Glen Barber wrote: >> On Thu, Apr 03, 2014 at 09:47:02AM +0200, Torbjorn Granlund wrote: >>> Glen Barber <g...@freebsd.org> writes: >>> >>> It is not a doc problem. >>> The issue is specific to certain hardware configurations, and >>> unless >>> anyone has made any breakthroughs that I am unaware of, the cause is >>> still unknown. >>> It happens on: >>> >>> AMD piledriver running Linux+KVM >>> AMD piledriver running Linux+Xen >>> Intel Nehalem running NetBSD+Xen >>> Intel Sandybridge running NetBSD+Xen >>> Intel Haswell running NetBSD+Xen >>> AMD K10 Barcelona running NetBSD+Xen >>> AMD Bulldozer running NetBSD+Xen >>> >> We need more specifics. >> >>> I've seen the laughable claim that this is a "bug in Virtualbox", and >>> now >>> the major downplay at http://www.freebsd.org/releases/10.0R/errata.html, >>> where this is a minor hardware specific problem. >>> >>> I have not found one piece of PC hardware where it does not happen under >>> virtualisation. Please let me know some configuration where >>> FreeBSD/i386 >>> works under a type 1 virtualiser? Perhaps Bhyve is FreeBSD-compatible? >>> >> Does not happen on my VirtualBox host. >> >> Glen >> > I've been following this discussion with some alarm, but have now looked > at the Errata: > > ------------------------------------------ > > "FreeBSD/i386 10.0-RELEASE running as a guest operating system > onVirtualBoxcan have a problem with disk I/O access. It depends on some > specific hardware configuration and does not depend on a specific > version ofVirtualBoxor host operating system. > > It causes various errors and makes FreeBSD quite unstable. Although the > cause is still unclear, disabling unmapped I/O works as a workaround." > etcetera > > ------------------------------------- > > I don't read this as "down-playing" - it's up front about saying that > there's a problem with every version of VirtualBox. It would, of course, > be useful to add that it doesn't work with other named emulators too > (for a virtual machine IS emulating the I/O hardware).
Not very much detail has been provided about what exactly 'is not working' in these other hypervisors. I would hesitate to write that FreeBSD 10 doesn't work in Xen from a single user report, when Colin Percival has FreeBSD 10 images for 32bit Amazon EC2 (Xen) that I've heard no reports of problems with http://www.daemonology.net/freebsd-on-ec2/ > > My concern was that this bug may be present on the real hardware too. I > suspect more people would be running an i386 version as a VM than on > real metal these days. > > Does the problem exist on previous releases? The 'unmapped IO' feature was added in FreeBSD 10, so the feature that is related to (if not causing) the problem is new. > > It seems to me that, after research, the list of confirmed incompatible > configurations need to be expanded, especially to encompass other > known-to-fail emulations. A list of "confirmed" problem environments > would make readers wary about untested emulators too. > > Incidentally, I don't see this as a bug in FreeBSD. A hypervisor is > supposed to transparent to the OS, emulating the hardware that the OS > thinks it has, to perfection. This is a broken VM, as clearly it's not > behaving as the real hardware would. Or is it? > > Regards, Frank. > > _______________________________________________ > freebsd-doc@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-doc > To unsubscribe, send any mail to "freebsd-doc-unsubscr...@freebsd.org" -- Allan Jude
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