From 3260ab5616b4cd049c79c342617525456a2391b2 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 29 Aug 2016 08:48:42 +0200 Subject: [PATCH 1/7] xen: Sync xen header Import the actual version of include/xen/interface/sched.h from Xen. Signed-off-by: Juergen Gross Signed-off-by: Peter Zijlstra (Intel) Acked-by: David Vrabel 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: 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/1472453327-19050-2-git-send-email-jgross@suse.com Signed-off-by: Ingo Molnar --- include/xen/interface/sched.h | 100 ++++++++++++++++++++++++++++------ 1 file changed, 82 insertions(+), 18 deletions(-) diff --git a/include/xen/interface/sched.h b/include/xen/interface/sched.h index f18490985fc8..a4c4d735d781 100644 --- a/include/xen/interface/sched.h +++ b/include/xen/interface/sched.h @@ -3,6 +3,24 @@ * * Scheduler state interactions * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to + * deal in the Software without restriction, including without limitation the + * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or + * sell copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + * * Copyright (c) 2005, Keir Fraser */ @@ -11,19 +29,31 @@ #include +/* + * Guest Scheduler Operations + * + * The SCHEDOP interface provides mechanisms for a guest to interact + * with the scheduler, including yield, blocking and shutting itself + * down. + */ + /* * The prototype for this hypercall is: - * long sched_op_new(int cmd, void *arg) + * long HYPERVISOR_sched_op(enum sched_op cmd, void *arg, ...) + * * @cmd == SCHEDOP_??? (scheduler operation). * @arg == Operation-specific extra argument(s), as described below. + * ... == Additional Operation-specific extra arguments, described below. * - * **NOTE**: - * Versions of Xen prior to 3.0.2 provide only the following legacy version + * Versions of Xen prior to 3.0.2 provided only the following legacy version * of this hypercall, supporting only the commands yield, block and shutdown: * long sched_op(int cmd, unsigned long arg) * @cmd == SCHEDOP_??? (scheduler operation). * @arg == 0 (SCHEDOP_yield and SCHEDOP_block) * == SHUTDOWN_* code (SCHEDOP_shutdown) + * + * This legacy version is available to new guests as: + * long HYPERVISOR_sched_op_compat(enum sched_op cmd, unsigned long arg) */ /* @@ -44,12 +74,17 @@ /* * Halt execution of this domain (all VCPUs) and notify the system controller. * @arg == pointer to sched_shutdown structure. + * + * If the sched_shutdown_t reason is SHUTDOWN_suspend then + * x86 PV guests must also set RDX (EDX for 32-bit guests) to the MFN + * of the guest's start info page. RDX/EDX is the third hypercall + * argument. + * + * In addition, which reason is SHUTDOWN_suspend this hypercall + * returns 1 if suspend was cancelled or the domain was merely + * checkpointed, and 0 if it is resuming in a new domain. */ #define SCHEDOP_shutdown 2 -struct sched_shutdown { - unsigned int reason; /* SHUTDOWN_* */ -}; -DEFINE_GUEST_HANDLE_STRUCT(sched_shutdown); /* * Poll a set of event-channel ports. Return when one or more are pending. An @@ -57,12 +92,6 @@ DEFINE_GUEST_HANDLE_STRUCT(sched_shutdown); * @arg == pointer to sched_poll structure. */ #define SCHEDOP_poll 3 -struct sched_poll { - GUEST_HANDLE(evtchn_port_t) ports; - unsigned int nr_ports; - uint64_t timeout; -}; -DEFINE_GUEST_HANDLE_STRUCT(sched_poll); /* * Declare a shutdown for another domain. The main use of this function is @@ -71,15 +100,11 @@ DEFINE_GUEST_HANDLE_STRUCT(sched_poll); * @arg == pointer to sched_remote_shutdown structure. */ #define SCHEDOP_remote_shutdown 4 -struct sched_remote_shutdown { - domid_t domain_id; /* Remote domain ID */ - unsigned int reason; /* SHUTDOWN_xxx reason */ -}; /* * Latch a shutdown code, so that when the domain later shuts down it * reports this code to the control tools. - * @arg == as for SCHEDOP_shutdown. + * @arg == sched_shutdown, as for SCHEDOP_shutdown. */ #define SCHEDOP_shutdown_code 5 @@ -92,10 +117,47 @@ struct sched_remote_shutdown { * With id != 0 and timeout != 0, poke watchdog timer and set new timeout. */ #define SCHEDOP_watchdog 6 + +/* + * Override the current vcpu affinity by pinning it to one physical cpu or + * undo this override restoring the previous affinity. + * @arg == pointer to sched_pin_override structure. + * + * A negative pcpu value will undo a previous pin override and restore the + * previous cpu affinity. + * This call is allowed for the hardware domain only and requires the cpu + * to be part of the domain's cpupool. + */ +#define SCHEDOP_pin_override 7 + +struct sched_shutdown { + unsigned int reason; /* SHUTDOWN_* => shutdown reason */ +}; +DEFINE_GUEST_HANDLE_STRUCT(sched_shutdown); + +struct sched_poll { + GUEST_HANDLE(evtchn_port_t) ports; + unsigned int nr_ports; + uint64_t timeout; +}; +DEFINE_GUEST_HANDLE_STRUCT(sched_poll); + +struct sched_remote_shutdown { + domid_t domain_id; /* Remote domain ID */ + unsigned int reason; /* SHUTDOWN_* => shutdown reason */ +}; +DEFINE_GUEST_HANDLE_STRUCT(sched_remote_shutdown); + struct sched_watchdog { uint32_t id; /* watchdog ID */ uint32_t timeout; /* timeout */ }; +DEFINE_GUEST_HANDLE_STRUCT(sched_watchdog); + +struct sched_pin_override { + int32_t pcpu; +}; +DEFINE_GUEST_HANDLE_STRUCT(sched_pin_override); /* * Reason codes for SCHEDOP_shutdown. These may be interpreted by control @@ -107,6 +169,7 @@ struct sched_watchdog { #define SHUTDOWN_suspend 2 /* Clean up, save suspend info, kill. */ #define SHUTDOWN_crash 3 /* Tell controller we've crashed. */ #define SHUTDOWN_watchdog 4 /* Restart because watchdog time expired. */ + /* * Domain asked to perform 'soft reset' for it. The expected behavior is to * reset internal Xen state for the domain returning it to the point where it @@ -115,5 +178,6 @@ struct sched_watchdog { * interfaces again. */ #define SHUTDOWN_soft_reset 5 +#define SHUTDOWN_MAX 5 /* Maximum valid shutdown reason. */ #endif /* __XEN_PUBLIC_SCHED_H__ */ From 47ae4b05d0fa2f2a998ebaf34d2dcbffca56a9db Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 29 Aug 2016 08:48:43 +0200 Subject: [PATCH 2/7] 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 --- MAINTAINERS | 1 + arch/x86/include/asm/hypervisor.h | 4 ++++ arch/x86/kernel/cpu/hypervisor.c | 11 +++++++++++ include/linux/hypervisor.h | 17 +++++++++++++++++ kernel/smp.c | 1 + kernel/up.c | 1 + 6 files changed, 35 insertions(+) create mode 100644 include/linux/hypervisor.h diff --git a/MAINTAINERS b/MAINTAINERS index db814a89599c..95151aab3445 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -8845,6 +8845,7 @@ S: Supported F: Documentation/virtual/paravirt_ops.txt F: arch/*/kernel/paravirt* F: arch/*/include/asm/paravirt.h +F: include/linux/hypervisor.h PARIDE DRIVERS FOR PARALLEL PORT IDE DEVICES M: Tim Waugh diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h index 055ea9941dd5..67942b6ad4b7 100644 --- a/arch/x86/include/asm/hypervisor.h +++ b/arch/x86/include/asm/hypervisor.h @@ -43,6 +43,9 @@ struct hypervisor_x86 { /* X2APIC detection (run once per boot) */ bool (*x2apic_available)(void); + + /* pin current vcpu to specified physical cpu (run rarely) */ + void (*pin_vcpu)(int); }; extern const struct hypervisor_x86 *x86_hyper; @@ -56,6 +59,7 @@ extern const struct hypervisor_x86 x86_hyper_kvm; extern void init_hypervisor(struct cpuinfo_x86 *c); extern void init_hypervisor_platform(void); extern bool hypervisor_x2apic_available(void); +extern void hypervisor_pin_vcpu(int cpu); #else static inline void init_hypervisor(struct cpuinfo_x86 *c) { } static inline void init_hypervisor_platform(void) { } diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c index 27e46658ebe3..35691a6b0d32 100644 --- a/arch/x86/kernel/cpu/hypervisor.c +++ b/arch/x86/kernel/cpu/hypervisor.c @@ -86,3 +86,14 @@ bool __init hypervisor_x2apic_available(void) x86_hyper->x2apic_available && x86_hyper->x2apic_available(); } + +void hypervisor_pin_vcpu(int cpu) +{ + if (!x86_hyper) + return; + + if (x86_hyper->pin_vcpu) + x86_hyper->pin_vcpu(cpu); + else + WARN_ONCE(1, "vcpu pinning requested but not supported!\n"); +} diff --git a/include/linux/hypervisor.h b/include/linux/hypervisor.h new file mode 100644 index 000000000000..3fa5ef2b3759 --- /dev/null +++ b/include/linux/hypervisor.h @@ -0,0 +1,17 @@ +#ifndef __LINUX_HYPEVISOR_H +#define __LINUX_HYPEVISOR_H + +/* + * Generic Hypervisor support + * Juergen Gross + */ + +#ifdef CONFIG_HYPERVISOR_GUEST +#include +#else +static inline void hypervisor_pin_vcpu(int cpu) +{ +} +#endif + +#endif /* __LINUX_HYPEVISOR_H */ 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) From df8ce9d78a4e7fbe7ddfd8ccee3ecaaa0013e883 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 29 Aug 2016 08:48:44 +0200 Subject: [PATCH 3/7] 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(+) 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); From 99bc67536d04bcb9133546284acfb15d033b8bfe Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 29 Aug 2016 08:48:45 +0200 Subject: [PATCH 4/7] xen: Add xen_pin_vcpu() to support calling functions on a dedicated pCPU Some hardware models (e.g. Dell Studio 1555 laptops) require calls to the firmware to be issued on CPU 0 only. As Dom0 might have to use these calls, add xen_pin_vcpu() to achieve this functionality. In case either the domain doesn't have the privilege to make the related hypercall or the hypervisor isn't supporting it, issue a warning once and disable further pinning attempts. Signed-off-by: Juergen Gross Signed-off-by: Peter Zijlstra (Intel) Acked-by: David Vrabel 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: 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/1472453327-19050-5-git-send-email-jgross@suse.com Signed-off-by: Ingo Molnar --- arch/x86/xen/enlighten.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index b86ebb1a9a7f..bc9aaba01a22 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1925,6 +1925,45 @@ static void xen_set_cpu_features(struct cpuinfo_x86 *c) } } +static void xen_pin_vcpu(int cpu) +{ + static bool disable_pinning; + struct sched_pin_override pin_override; + int ret; + + if (disable_pinning) + return; + + pin_override.pcpu = cpu; + ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override); + + /* Ignore errors when removing override. */ + if (cpu < 0) + return; + + switch (ret) { + case -ENOSYS: + pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n", + cpu); + disable_pinning = true; + break; + case -EPERM: + WARN(1, "Trying to pin vcpu without having privilege to do so\n"); + disable_pinning = true; + break; + case -EINVAL: + case -EBUSY: + pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n", + cpu); + break; + case 0: + break; + default: + WARN(1, "rc %d while trying to pin vcpu\n", ret); + disable_pinning = true; + } +} + const struct hypervisor_x86 x86_hyper_xen = { .name = "Xen", .detect = xen_platform, @@ -1933,6 +1972,7 @@ const struct hypervisor_x86 x86_hyper_xen = { #endif .x2apic_available = xen_x2apic_para_available, .set_cpu_features = xen_set_cpu_features, + .pin_vcpu = xen_pin_vcpu, }; EXPORT_SYMBOL(x86_hyper_xen); From e23f22b5cb9e44da24cb8494707536211adff8d1 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 29 Aug 2016 08:48:46 +0200 Subject: [PATCH 5/7] dcdbas: Make use of smp_call_on_cpu() Use smp_call_on_cpu() to raise SMI on CPU 0. Make call secure by adding get_online_cpus() to avoid e.g. suspend resume cycles in between. 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/1472453327-19050-6-git-send-email-jgross@suse.com Signed-off-by: Ingo Molnar --- drivers/firmware/dcdbas.c | 51 ++++++++++++++++++++------------------- 1 file changed, 26 insertions(+), 25 deletions(-) diff --git a/drivers/firmware/dcdbas.c b/drivers/firmware/dcdbas.c index 829eec8959f2..2fe1a130189f 100644 --- a/drivers/firmware/dcdbas.c +++ b/drivers/firmware/dcdbas.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include #include @@ -238,33 +239,14 @@ static ssize_t host_control_on_shutdown_store(struct device *dev, return count; } -/** - * dcdbas_smi_request: generate SMI request - * - * Called with smi_data_lock. - */ -int dcdbas_smi_request(struct smi_cmd *smi_cmd) +static int raise_smi(void *par) { - cpumask_var_t old_mask; - int ret = 0; + struct smi_cmd *smi_cmd = par; - if (smi_cmd->magic != SMI_CMD_MAGIC) { - dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n", - __func__); - return -EBADR; - } - - /* SMI requires CPU 0 */ - if (!alloc_cpumask_var(&old_mask, GFP_KERNEL)) - return -ENOMEM; - - cpumask_copy(old_mask, ¤t->cpus_allowed); - set_cpus_allowed_ptr(current, cpumask_of(0)); if (smp_processor_id() != 0) { dev_dbg(&dcdbas_pdev->dev, "%s: failed to get CPU 0\n", __func__); - ret = -EBUSY; - goto out; + return -EBUSY; } /* generate SMI */ @@ -280,9 +262,28 @@ int dcdbas_smi_request(struct smi_cmd *smi_cmd) : "memory" ); -out: - set_cpus_allowed_ptr(current, old_mask); - free_cpumask_var(old_mask); + return 0; +} +/** + * dcdbas_smi_request: generate SMI request + * + * Called with smi_data_lock. + */ +int dcdbas_smi_request(struct smi_cmd *smi_cmd) +{ + int ret; + + if (smi_cmd->magic != SMI_CMD_MAGIC) { + dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n", + __func__); + return -EBADR; + } + + /* SMI requires CPU 0 */ + get_online_cpus(); + ret = smp_call_on_cpu(0, raise_smi, smi_cmd, true); + put_online_cpus(); + return ret; } From 27046a3ffbb01ba715e6236c170701c84759b61d Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 29 Aug 2016 08:48:47 +0200 Subject: [PATCH 6/7] hwmon: Use smp_call_on_cpu() for dell-smm i8k Use the smp_call_on_cpu() function to call system management mode on CPU 0. Make call secure by adding get_online_cpus() to avoid e.g. suspend resume cycles in between. 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/1472453327-19050-7-git-send-email-jgross@suse.com Signed-off-by: Ingo Molnar --- drivers/hwmon/dell-smm-hwmon.c | 36 +++++++++++++++++++--------------- 1 file changed, 20 insertions(+), 16 deletions(-) diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c index acf9c0361d9f..34704b0451b4 100644 --- a/drivers/hwmon/dell-smm-hwmon.c +++ b/drivers/hwmon/dell-smm-hwmon.c @@ -21,6 +21,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include #include #include #include @@ -36,6 +37,7 @@ #include #include #include +#include #include @@ -134,11 +136,11 @@ static inline const char *i8k_get_dmi_data(int field) /* * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard. */ -static int i8k_smm(struct smm_regs *regs) +static int i8k_smm_func(void *par) { int rc; + struct smm_regs *regs = par; int eax = regs->eax; - cpumask_var_t old_mask; #ifdef DEBUG int ebx = regs->ebx; @@ -149,16 +151,8 @@ static int i8k_smm(struct smm_regs *regs) #endif /* SMM requires CPU 0 */ - if (!alloc_cpumask_var(&old_mask, GFP_KERNEL)) - return -ENOMEM; - cpumask_copy(old_mask, ¤t->cpus_allowed); - rc = set_cpus_allowed_ptr(current, cpumask_of(0)); - if (rc) - goto out; - if (smp_processor_id() != 0) { - rc = -EBUSY; - goto out; - } + if (smp_processor_id() != 0) + return -EBUSY; #if defined(CONFIG_X86_64) asm volatile("pushq %%rax\n\t" @@ -216,10 +210,6 @@ static int i8k_smm(struct smm_regs *regs) if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax) rc = -EINVAL; -out: - set_cpus_allowed_ptr(current, old_mask); - free_cpumask_var(old_mask); - #ifdef DEBUG rettime = ktime_get(); delta = ktime_sub(rettime, calltime); @@ -231,6 +221,20 @@ out: return rc; } +/* + * Call the System Management Mode BIOS. + */ +static int i8k_smm(struct smm_regs *regs) +{ + int ret; + + get_online_cpus(); + ret = smp_call_on_cpu(0, i8k_smm_func, regs, true); + put_online_cpus(); + + return ret; +} + /* * Read the fan status. */ From 8db549491c4a3ce9e1d509b75f78516e497f48ec Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sun, 11 Sep 2016 10:36:26 +0200 Subject: [PATCH 7/7] 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(-) 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;