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VirtualBox hotfix now available for OS X 10.8.2 problem

virtualbox.org

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Re: VirtualBox hotfix now available for OS X 10.8.2 problem

#12

Post by 0x0 »

mitchellh wrote: post #6

Let me go over the anatomy of the actual bug, to the best of my understanding, so that people can better understanding what is going on here. Note that I'm the Vagrant creator, not a VirtualBox hacker, not a kernel hacker (though I've had my fair share of both in the past few years). There is a feature of Intel CPUs called VT-x extensions. Without going into detail: VT-x is set of features built natively into some in…

I'm curious to understand why only Ivy Bridge CPUs are affected, especially if this is a software accounting/refcounting bug. Also, there was talk about this not being an 10.8.2 bug, but a result of an EFI firmware upgrade. Anyone have any insight?

Re: VirtualBox hotfix now available for OS X 10.8.2 problem

#13

Post by mitchellh »

0x0 wrote: post #12
mitchellh wrote: post #6

Let me go over the anatomy of the actual bug, to the best of my understanding, so that people can better understanding what is going on here. Note that I'm the Vagrant creator, not a VirtualBox hacker, not a kernel hacker (though I've had my fair share of both in the past few years). There is a feature of Intel CPUs called VT-x extensions. Without going into detail: VT-x is set of features built natively into some in…

I'm curious to understand why only Ivy Bridge CPUs are affected, especially if this is a software accounting/refcounting bug. Also, there was talk about this not being an 10.8.2 bug, but a result of an EFI firmware upgrade. Anyone have any insight?

I'm not sure why only Ivy Bridge.

I can say though that the EFI firmware didn't cause the bug, but in fact the 10.8.2 software upgrade did.

Re: VirtualBox hotfix now available for OS X 10.8.2 problem

#14

Post by bdash »

mitchellh wrote: post #6

Let me go over the anatomy of the actual bug, to the best of my understanding, so that people can better understanding what is going on here. Note that I'm the Vagrant creator, not a VirtualBox hacker, not a kernel hacker (though I've had my fair share of both in the past few years). There is a feature of Intel CPUs called VT-x extensions. Without going into detail: VT-x is set of features built natively into some in…

I don't see how this explanation can be correct given the fact that the code using host_vmxon / host_vmxoff in the revision you point to is guarded by #if VBOX_WITH_HOST_VMX, which the changeset also shows is false. It wasn't turned on until the following revision: " rel="nofollow">https://www.virtualbox.org/changeset/43380/vbox>. I can't see how any change in behavior of host_vmxon / host_vmxoff in 10.8.2 could be the cause if they weren't even being called prior to this.

Re: VirtualBox hotfix now available for OS X 10.8.2 problem

#15

Post by sethmartin »

0x0 wrote: post #12
mitchellh wrote: post #6

Let me go over the anatomy of the actual bug, to the best of my understanding, so that people can better understanding what is going on here. Note that I'm the Vagrant creator, not a VirtualBox hacker, not a kernel hacker (though I've had my fair share of both in the past few years). There is a feature of Intel CPUs called VT-x extensions. Without going into detail: VT-x is set of features built natively into some in…

I'm curious to understand why only Ivy Bridge CPUs are affected, especially if this is a software accounting/refcounting bug. Also, there was talk about this not being an 10.8.2 bug, but a result of an EFI firmware upgrade. Anyone have any insight?

By a quirk of how the updates were delivered, I have 10.8.2 on my Air, but the EFI firmware is still to be installed. VirtualBox is very dead (but I can't wait to get it going again!).

Re: VirtualBox hotfix now available for OS X 10.8.2 problem

#18

Post by kevingadd »

mitchellh wrote: post #6

Let me go over the anatomy of the actual bug, to the best of my understanding, so that people can better understanding what is going on here. Note that I'm the Vagrant creator, not a VirtualBox hacker, not a kernel hacker (though I've had my fair share of both in the past few years). There is a feature of Intel CPUs called VT-x extensions. Without going into detail: VT-x is set of features built natively into some in…

I suspect that VT-x is off by default on many configurations due to poor reliability. I had to manually go in and enable VT-x on my laptop to use Vagrant, and doing so caused machine-wide hard locks every 30 minutes or so (only when the VirtualBox VM was running) that I had never seen before.
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