Commit e83ee6f7 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: selftests: Expand set of APIs for pinning tasks to a single CPU 

Expand kvm_pin_this_task_to_pcpu() into a set of APIs to allow pinning a
task (or self) to a CPU (any or specific).  This will allow deduplicating
code throughout a variety of selftests.

Opportunistically use "self" instead of "this_task" as it is both more
concise and less ambiguous.

Link: https://lore.kernel.org/r/20250626001225.744268-4-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent a7cec208

tools/testing/selftests/kvm/include/kvm_util.h

+30 −1
Original line number Diff line number Diff line
@@ -20,6 +20,8 @@ 


#include <sys/ioctl.h>



#include <pthread.h>



#include "kvm_util_arch.h"

#include "kvm_util_types.h"

#include "sparsebit.h"
@@ -1013,7 +1015,34 @@ struct kvm_vcpu *vm_recreate_with_one_vcpu(struct kvm_vm *vm); 


void kvm_set_files_rlimit(uint32_t nr_vcpus);



void kvm_pin_this_task_to_pcpu(uint32_t pcpu);

int __pin_task_to_cpu(pthread_t task, int cpu);



static inline void pin_task_to_cpu(pthread_t task, int cpu)

{

	int r;



	r = __pin_task_to_cpu(task, cpu);

	TEST_ASSERT(!r, "Failed to set thread affinity to pCPU '%u'", cpu);

}



static inline int pin_task_to_any_cpu(pthread_t task)

{

	int cpu = sched_getcpu();



	pin_task_to_cpu(task, cpu);

	return cpu;

}



static inline void pin_self_to_cpu(int cpu)

{

	pin_task_to_cpu(pthread_self(), cpu);

}



static inline int pin_self_to_any_cpu(void)

{

	return pin_task_to_any_cpu(pthread_self());

}



void kvm_print_vcpu_pinning_help(void);

void kvm_parse_vcpu_pinning(const char *pcpus_string, uint32_t vcpu_to_pcpu[],

			    int nr_vcpus);

tools/testing/selftests/kvm/lib/kvm_util.c

+7 −8
Original line number Diff line number Diff line
@@ -605,15 +605,14 @@ struct kvm_vcpu *vm_recreate_with_one_vcpu(struct kvm_vm *vm) 
	return vm_vcpu_recreate(vm, 0);

}



void kvm_pin_this_task_to_pcpu(uint32_t pcpu)

int __pin_task_to_cpu(pthread_t task, int cpu)

{

	cpu_set_t mask;

	int r;

	cpu_set_t cpuset;



	CPU_ZERO(&mask);

	CPU_SET(pcpu, &mask);

	r = sched_setaffinity(0, sizeof(mask), &mask);

	TEST_ASSERT(!r, "sched_setaffinity() failed for pCPU '%u'.", pcpu);

	CPU_ZERO(&cpuset);

	CPU_SET(cpu, &cpuset);



	return pthread_setaffinity_np(task, sizeof(cpuset), &cpuset);

}



static uint32_t parse_pcpu(const char *cpu_str, const cpu_set_t *allowed_mask)
@@ -667,7 +666,7 @@ void kvm_parse_vcpu_pinning(const char *pcpus_string, uint32_t vcpu_to_pcpu[], 


	/* 2. Check if the main worker needs to be pinned. */

	if (cpu) {

		kvm_pin_this_task_to_pcpu(parse_pcpu(cpu, &allowed_mask));

		pin_self_to_cpu(parse_pcpu(cpu, &allowed_mask));

		cpu = strtok(NULL, delim);

	}

tools/testing/selftests/kvm/lib/memstress.c

+1 −1
Original line number Diff line number Diff line
@@ -265,7 +265,7 @@ static void *vcpu_thread_main(void *data) 
	int vcpu_idx = vcpu->vcpu_idx;



	if (memstress_args.pin_vcpus)

		kvm_pin_this_task_to_pcpu(memstress_args.vcpu_to_pcpu[vcpu_idx]);

		pin_self_to_cpu(memstress_args.vcpu_to_pcpu[vcpu_idx]);



	WRITE_ONCE(vcpu->running, true);