diff options
| author | David Woodhouse <dwmw@amazon.co.uk> | 2018-05-20 20:51:10 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-22 16:57:59 +0200 |
| commit | 944e0fc51a89c9827b98813d65dc083274777c7f (patch) | |
| tree | 37de8f7a21f2a4f50f86763cd5b01873f542bcc4 /fs | |
| parent | b2d748b3a8d4e936a7e6e5fc9f04e2f9696efcc5 (diff) | |
x86/amd: don't set X86_BUG_SYSRET_SS_ATTRS when running under Xen
commit def9331a12977770cc6132d79f8e6565871e8e38 upstream
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>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
0 files changed, 0 insertions, 0 deletions