Messages in this thread | | | Date | Thu, 11 May 2017 14:46:58 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH v3] x86/amd: don't set X86_BUG_SYSRET_SS_ATTRS when running under Xen |
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On Thu, 11 May 2017, Juergen Gross wrote:
> On 27/04/17 07:01, Juergen Gross wrote: > > When running as Xen pv guest X86_BUG_SYSRET_SS_ATTRS must not be set > > on AMD cpus. > > > > This bug/feature bit is kind of special as it will be used very early > > when switching threads. Setting the bit and clearing it a little bit > > later leaves a critical window where things can go wrong. This time > > window has enlarged a little bit by using setup_clear_cpu_cap() instead > > of the hypervisor's set_cpu_features callback. It seems this larger > > window now makes it rather easy to hit the problem. > > > > The proper solution is to never set the bit in case of Xen. > > > > Signed-off-by: Juergen Gross <jgross@suse.com> > > Any objections for carrying this through the Xen tree?
Acked-by: Thomas Gleixner <tglx@linutronix.de>
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