On Thu, Apr 03, 2014 at 02:08:15PM +0100, 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 <[email protected]> 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). > > 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? >
No. > 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? > The cause is unclear. Glen
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