Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull cpu hotplug fixes from Thomas Gleixner:
"Two fixes for the cpu hotplug machinery:
- Replace the overly clever 'SMT disabled by BIOS' detection logic as
it breaks KVM scenarios and prevents speculation control updates
when the Hyperthreads are brought online late after boot.
- Remove a redundant invocation of the speculation control update
function"
* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM
x86/speculation: Remove redundant arch_smt_update() invocation
+9
-39
+1
-1
arch/x86/kernel/cpu/bugs.c
+1
-1
arch/x86/kernel/cpu/bugs.c
+2
-1
arch/x86/kvm/vmx/vmx.c
+2
-1
arch/x86/kvm/vmx/vmx.c
···
26
26
#include <linux/mod_devicetable.h>
27
27
#include <linux/mm.h>
28
28
#include <linux/sched.h>
29
+
#include <linux/sched/smt.h>
29
30
#include <linux/slab.h>
30
31
#include <linux/tboot.h>
31
32
#include <linux/trace_events.h>
···
6824
6823
* Warn upon starting the first VM in a potentially
6825
6824
* insecure environment.
6826
6825
*/
6827
-
if (cpu_smt_control == CPU_SMT_ENABLED)
6826
+
if (sched_smt_active())
6828
6827
pr_warn_once(L1TF_MSG_SMT);
6829
6828
if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_NEVER)
6830
6829
pr_warn_once(L1TF_MSG_L1D);
-2
include/linux/cpu.h
-2
include/linux/cpu.h
···
180
180
#if defined(CONFIG_SMP) && defined(CONFIG_HOTPLUG_SMT)
181
181
extern enum cpuhp_smt_control cpu_smt_control;
182
182
extern void cpu_smt_disable(bool force);
183
-
extern void cpu_smt_check_topology_early(void);
184
183
extern void cpu_smt_check_topology(void);
185
184
#else
186
185
# define cpu_smt_control (CPU_SMT_ENABLED)
187
186
static inline void cpu_smt_disable(bool force) { }
188
-
static inline void cpu_smt_check_topology_early(void) { }
189
187
static inline void cpu_smt_check_topology(void) { }
190
188
#endif
191
189
+5
-33
kernel/cpu.c
+5
-33
kernel/cpu.c
···
376
376
377
377
#ifdef CONFIG_HOTPLUG_SMT
378
378
enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED;
379
-
EXPORT_SYMBOL_GPL(cpu_smt_control);
380
-
381
-
static bool cpu_smt_available __read_mostly;
382
379
383
380
void __init cpu_smt_disable(bool force)
384
381
{
···
394
397
395
398
/*
396
399
* The decision whether SMT is supported can only be done after the full
397
-
* CPU identification. Called from architecture code before non boot CPUs
398
-
* are brought up.
399
-
*/
400
-
void __init cpu_smt_check_topology_early(void)
401
-
{
402
-
if (!topology_smt_supported())
403
-
cpu_smt_control = CPU_SMT_NOT_SUPPORTED;
404
-
}
405
-
406
-
/*
407
-
* If SMT was disabled by BIOS, detect it here, after the CPUs have been
408
-
* brought online. This ensures the smt/l1tf sysfs entries are consistent
409
-
* with reality. cpu_smt_available is set to true during the bringup of non
410
-
* boot CPUs when a SMT sibling is detected. Note, this may overwrite
411
-
* cpu_smt_control's previous setting.
400
+
* CPU identification. Called from architecture code.
412
401
*/
413
402
void __init cpu_smt_check_topology(void)
414
403
{
415
-
if (!cpu_smt_available)
404
+
if (!topology_smt_supported())
416
405
cpu_smt_control = CPU_SMT_NOT_SUPPORTED;
417
406
}
418
407
···
411
428
412
429
static inline bool cpu_smt_allowed(unsigned int cpu)
413
430
{
414
-
if (topology_is_primary_thread(cpu))
431
+
if (cpu_smt_control == CPU_SMT_ENABLED)
415
432
return true;
416
433
417
-
/*
418
-
* If the CPU is not a 'primary' thread and the booted_once bit is
419
-
* set then the processor has SMT support. Store this information
420
-
* for the late check of SMT support in cpu_smt_check_topology().
421
-
*/
422
-
if (per_cpu(cpuhp_state, cpu).booted_once)
423
-
cpu_smt_available = true;
424
-
425
-
if (cpu_smt_control == CPU_SMT_ENABLED)
434
+
if (topology_is_primary_thread(cpu))
426
435
return true;
427
436
428
437
/*
···
2065
2090
*/
2066
2091
cpuhp_offline_cpu_device(cpu);
2067
2092
}
2068
-
if (!ret) {
2093
+
if (!ret)
2069
2094
cpu_smt_control = ctrlval;
2070
-
arch_smt_update();
2071
-
}
2072
2095
cpu_maps_update_done();
2073
2096
return ret;
2074
2097
}
···
2077
2104
2078
2105
cpu_maps_update_begin();
2079
2106
cpu_smt_control = CPU_SMT_ENABLED;
2080
-
arch_smt_update();
2081
2107
for_each_present_cpu(cpu) {
2082
2108
/* Skip online CPUs and CPUs on offline nodes */
2083
2109
if (cpu_online(cpu) || !node_online(cpu_to_node(cpu)))
+1
kernel/sched/fair.c
+1
kernel/sched/fair.c