Files
linux/kernel
Josh Poimboeuf 8b1969db55 cpu/hotplug: detect SMT disabled by BIOS
commit 73d5e2b472 upstream

If SMT is disabled in BIOS, the CPU code doesn't properly detect it.
The /sys/devices/system/cpu/smt/control file shows 'on', and the 'l1tf'
vulnerabilities file shows SMT as vulnerable.

Fix it by forcing 'cpu_smt_control' to CPU_SMT_NOT_SUPPORTED in such a
case.  Unfortunately the detection can only be done after bringing all
the CPUs online, so we have to overwrite any previous writes to the
variable.

Reported-by: Joe Mario <jmario@redhat.com>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Fixes: f048c399e0 ("x86/topology: Provide topology_smt_supported()")
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-15 18:14:51 +02:00
..
2018-05-30 07:50:51 +02:00
2017-09-02 07:07:53 +02:00
2016-01-22 18:04:28 -05:00
2016-04-04 09:46:47 -04:00
2018-08-15 18:14:51 +02:00
2015-04-12 21:03:31 +02:00
2015-11-23 09:44:58 +01:00
2018-08-03 07:55:12 +02:00
2016-02-16 13:04:58 -05:00
2017-05-20 14:28:40 +02:00
2017-07-05 14:40:24 +02:00
2015-01-17 10:02:23 +13:00
2016-03-01 20:36:56 +01:00
2018-08-03 07:55:24 +02:00
2018-05-09 09:50:20 +02:00
2016-09-22 20:00:36 -05:00