Re: [PATCH 1/3] KVM: x86 emulator: Fix task switch privilege checks

[Joerg Roedel <joerg.roedel@amd.com>]

On Fri, Jan 27, 2012 at 02:55:12PM +0100, Kevin Wolf wrote:
> Am 27.01.2012 14:34, schrieb Joerg Roedel:
> > On Fri, Jan 27, 2012 at 01:58:38PM +0100, Kevin Wolf wrote:
> >> Am 25.01.2012 17:00, schrieb Joerg Roedel:
> > 
> >> I just retried. I use kvm-kmod and kvm.git with HEAD at ff92e9b5 plus
> >> the tree patches of this series plus a printk to output exit_int_info in
> >> task_switch_intercept(). I ran taskswitch2 from kvm-unittests and got
> >> two failures and my VM86 unit test which hung when trying to return from
> >> VM86. I also ran the kernel that made me aware of the issue initially.
> >> All debug messages show exit_int_info = 0.
> > 
> > Okay, you are testing on a K8 which has exactly this bug. As I just
> > found out it is documented as erratum 701. The good news is that this
> > only happens on K8 and Fam11h, any later AMD processor doesn't have this
> > bug.
> 
> Meh. Unless you give me a newer processor, this doesn't really help
> me... Doesn't look like there's any way to get a workaround, is there? I
> guess I'll have to hack it locally and possibly break other guests with
> the hacked module.

No, unfortunatly there is no workaround for this problem. How do you
plan to hack around it?


	Joerg

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