From 47ae4b05d0fa2f2a998ebaf34d2dcbffca56a9db Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 29 Aug 2016 08:48:43 +0200 Subject: virt, sched: Add generic vCPU pinning support Add generic virtualization support for pinning the current vCPU to a specified physical CPU. As this operation isn't performance critical (a very limited set of operations like BIOS calls and SMIs is expected to need this) just add a hypervisor specific indirection. Signed-off-by: Juergen Gross Signed-off-by: Peter Zijlstra (Intel) Cc: Douglas_Warzecha@dell.com Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akataria@vmware.com Cc: boris.ostrovsky@oracle.com Cc: chrisw@sous-sol.org Cc: david.vrabel@citrix.com Cc: hpa@zytor.com Cc: jdelvare@suse.com Cc: jeremy@goop.org Cc: linux@roeck-us.net Cc: pali.rohar@gmail.com Cc: rusty@rustcorp.com.au Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1472453327-19050-3-git-send-email-jgross@suse.com Signed-off-by: Ingo Molnar --- kernel/smp.c | 1 + kernel/up.c | 1 + 2 files changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/smp.c b/kernel/smp.c index 3aa642d39c03..4274ca5f3bbc 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "smpboot.h" diff --git a/kernel/up.c b/kernel/up.c index 1760bf3d1463..3ccee2bd13ba 100644 --- a/kernel/up.c +++ b/kernel/up.c @@ -6,6 +6,7 @@ #include #include #include +#include int smp_call_function_single(int cpu, void (*func) (void *info), void *info, int wait) -- cgit v1.2.3-59-g8ed1b From df8ce9d78a4e7fbe7ddfd8ccee3ecaaa0013e883 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 29 Aug 2016 08:48:44 +0200 Subject: smp: Add function to execute a function synchronously on a CPU On some hardware models (e.g. Dell Studio 1555 laptop) some hardware related functions (e.g. SMIs) are to be executed on physical CPU 0 only. Instead of open coding such a functionality multiple times in the kernel add a service function for this purpose. This will enable the possibility to take special measures in virtualized environments like Xen, too. Signed-off-by: Juergen Gross Signed-off-by: Peter Zijlstra (Intel) Cc: Douglas_Warzecha@dell.com Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akataria@vmware.com Cc: boris.ostrovsky@oracle.com Cc: chrisw@sous-sol.org Cc: david.vrabel@citrix.com Cc: hpa@zytor.com Cc: jdelvare@suse.com Cc: jeremy@goop.org Cc: linux@roeck-us.net Cc: pali.rohar@gmail.com Cc: rusty@rustcorp.com.au Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1472453327-19050-4-git-send-email-jgross@suse.com Signed-off-by: Ingo Molnar --- include/linux/smp.h | 3 +++ kernel/smp.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ kernel/up.c | 17 +++++++++++++++++ 3 files changed, 70 insertions(+) (limited to 'kernel') diff --git a/include/linux/smp.h b/include/linux/smp.h index eccae4690f41..8e0cb7a0f836 100644 --- a/include/linux/smp.h +++ b/include/linux/smp.h @@ -196,6 +196,9 @@ extern void arch_enable_nonboot_cpus_end(void); void smp_setup_processor_id(void); +int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, + bool phys); + /* SMP core functions */ int smpcfd_prepare_cpu(unsigned int cpu); int smpcfd_dead_cpu(unsigned int cpu); diff --git a/kernel/smp.c b/kernel/smp.c index 4274ca5f3bbc..f4f6137941cb 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -725,3 +725,53 @@ void wake_up_all_idle_cpus(void) preempt_enable(); } EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus); + +/** + * smp_call_on_cpu - Call a function on a specific cpu + * + * Used to call a function on a specific cpu and wait for it to return. + * Optionally make sure the call is done on a specified physical cpu via vcpu + * pinning in order to support virtualized environments. + */ +struct smp_call_on_cpu_struct { + struct work_struct work; + struct completion done; + int (*func)(void *); + void *data; + int ret; + int cpu; +}; + +static void smp_call_on_cpu_callback(struct work_struct *work) +{ + struct smp_call_on_cpu_struct *sscs; + + sscs = container_of(work, struct smp_call_on_cpu_struct, work); + if (sscs->cpu >= 0) + hypervisor_pin_vcpu(sscs->cpu); + sscs->ret = sscs->func(sscs->data); + if (sscs->cpu >= 0) + hypervisor_pin_vcpu(-1); + + complete(&sscs->done); +} + +int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys) +{ + struct smp_call_on_cpu_struct sscs = { + .work = __WORK_INITIALIZER(sscs.work, smp_call_on_cpu_callback), + .done = COMPLETION_INITIALIZER_ONSTACK(sscs.done), + .func = func, + .data = par, + .cpu = phys ? cpu : -1, + }; + + if (cpu >= nr_cpu_ids || !cpu_online(cpu)) + return -ENXIO; + + queue_work_on(cpu, system_wq, &sscs.work); + wait_for_completion(&sscs.done); + + return sscs.ret; +} +EXPORT_SYMBOL_GPL(smp_call_on_cpu); diff --git a/kernel/up.c b/kernel/up.c index 3ccee2bd13ba..ee81ac9af4ca 100644 --- a/kernel/up.c +++ b/kernel/up.c @@ -83,3 +83,20 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info), preempt_enable(); } EXPORT_SYMBOL(on_each_cpu_cond); + +int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys) +{ + int ret; + + if (cpu != 0) + return -ENXIO; + + if (phys) + hypervisor_pin_vcpu(0); + ret = func(par); + if (phys) + hypervisor_pin_vcpu(-1); + + return ret; +} +EXPORT_SYMBOL_GPL(smp_call_on_cpu); -- cgit v1.2.3-59-g8ed1b From 8db549491c4a3ce9e1d509b75f78516e497f48ec Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sun, 11 Sep 2016 10:36:26 +0200 Subject: smp: Allocate smp_call_on_cpu() workqueue on stack too The SMP IPI struct descriptor is allocated on the stack except for the workqueue and lockdep complains: INFO: trying to register non-static key. the code is fine but needs lockdep annotation. turning off the locking correctness validator. CPU: 0 PID: 110 Comm: kworker/0:1 Not tainted 4.8.0-rc5+ #14 Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A13 05/11/2014 Workqueue: events smp_call_on_cpu_callback ... Call Trace: dump_stack register_lock_class ? __lock_acquire __lock_acquire ? __lock_acquire lock_acquire ? process_one_work process_one_work ? process_one_work worker_thread ? process_one_work ? process_one_work kthread ? kthread_create_on_node ret_from_fork So allocate it on the stack too. Signed-off-by: Peter Zijlstra (Intel) [ Test and write commit message. ] Signed-off-by: Borislav Petkov Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20160911084323.jhtnpb4b37t5tlno@pd.tnic Signed-off-by: Ingo Molnar --- kernel/smp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/smp.c b/kernel/smp.c index f4f6137941cb..bba3b201668d 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -759,13 +759,14 @@ static void smp_call_on_cpu_callback(struct work_struct *work) int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys) { struct smp_call_on_cpu_struct sscs = { - .work = __WORK_INITIALIZER(sscs.work, smp_call_on_cpu_callback), .done = COMPLETION_INITIALIZER_ONSTACK(sscs.done), .func = func, .data = par, .cpu = phys ? cpu : -1, }; + INIT_WORK_ONSTACK(&sscs.work, smp_call_on_cpu_callback); + if (cpu >= nr_cpu_ids || !cpu_online(cpu)) return -ENXIO; -- cgit v1.2.3-59-g8ed1b