Commit 9b56532b authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: selftests: Adjust number of files rlimit for all "standard" VMs 

Move the max vCPUs test's RLIMIT_NOFILE adjustments to common code, and
use the new helper to adjust the resource limit for non-barebones VMs by
default.  x86's recalc_apic_map_test creates 512 vCPUs, and a future
change will open the binary stats fd for all vCPUs, which will put the
recalc APIC test above some distros' default limit of 1024.

Link: https://lore.kernel.org/r/20250111005049.1247555-8-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent ea7179f9

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

+2 −0
Original line number Diff line number Diff line
@@ -966,6 +966,8 @@ static inline struct kvm_vm *vm_create_shape_with_one_vcpu(struct vm_shape shape 


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);

void kvm_print_vcpu_pinning_help(void);

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

tools/testing/selftests/kvm/kvm_create_max_vcpus.c

+1 −27
Original line number Diff line number Diff line
@@ -10,7 +10,6 @@ 
#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/resource.h>



#include "test_util.h"
@@ -39,36 +38,11 @@ int main(int argc, char *argv[]) 
{

	int kvm_max_vcpu_id = kvm_check_cap(KVM_CAP_MAX_VCPU_ID);

	int kvm_max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);

	/*

	 * Number of file descriptors reqired, KVM_CAP_MAX_VCPUS for vCPU fds +

	 * an arbitrary number for everything else.

	 */

	int nr_fds_wanted = kvm_max_vcpus + 100;

	struct rlimit rl;



	pr_info("KVM_CAP_MAX_VCPU_ID: %d\n", kvm_max_vcpu_id);

	pr_info("KVM_CAP_MAX_VCPUS: %d\n", kvm_max_vcpus);



	/*

	 * Check that we're allowed to open nr_fds_wanted file descriptors and

	 * try raising the limits if needed.

	 */

	TEST_ASSERT(!getrlimit(RLIMIT_NOFILE, &rl), "getrlimit() failed!");



	if (rl.rlim_cur < nr_fds_wanted) {

		rl.rlim_cur = nr_fds_wanted;

		if (rl.rlim_max < nr_fds_wanted) {

			int old_rlim_max = rl.rlim_max;

			rl.rlim_max = nr_fds_wanted;



			int r = setrlimit(RLIMIT_NOFILE, &rl);

			__TEST_REQUIRE(r >= 0,

				       "RLIMIT_NOFILE hard limit is too low (%d, wanted %d)",

				       old_rlim_max, nr_fds_wanted);

		} else {

			TEST_ASSERT(!setrlimit(RLIMIT_NOFILE, &rl), "setrlimit() failed!");

		}

	}

	kvm_set_files_rlimit(kvm_max_vcpus);



	/*

	 * Upstream KVM prior to 4.8 does not support KVM_CAP_MAX_VCPU_ID.

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

+34 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <assert.h>

#include <sched.h>

#include <sys/mman.h>

#include <sys/resource.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <unistd.h>
@@ -411,6 +412,37 @@ static uint64_t vm_nr_pages_required(enum vm_guest_mode mode, 
	return vm_adjust_num_guest_pages(mode, nr_pages);

}



void kvm_set_files_rlimit(uint32_t nr_vcpus)

{

	/*

	 * Number of file descriptors required, nr_vpucs vCPU fds + an arbitrary

	 * number for everything else.

	 */

	int nr_fds_wanted = nr_vcpus + 100;

	struct rlimit rl;



	/*

	 * Check that we're allowed to open nr_fds_wanted file descriptors and

	 * try raising the limits if needed.

	 */

	TEST_ASSERT(!getrlimit(RLIMIT_NOFILE, &rl), "getrlimit() failed!");



	if (rl.rlim_cur < nr_fds_wanted) {

		rl.rlim_cur = nr_fds_wanted;

		if (rl.rlim_max < nr_fds_wanted) {

			int old_rlim_max = rl.rlim_max;



			rl.rlim_max = nr_fds_wanted;

			__TEST_REQUIRE(setrlimit(RLIMIT_NOFILE, &rl) >= 0,

				       "RLIMIT_NOFILE hard limit is too low (%d, wanted %d)",

				       old_rlim_max, nr_fds_wanted);

		} else {

			TEST_ASSERT(!setrlimit(RLIMIT_NOFILE, &rl), "setrlimit() failed!");

		}

	}



}



struct kvm_vm *__vm_create(struct vm_shape shape, uint32_t nr_runnable_vcpus,

			   uint64_t nr_extra_pages)

{
@@ -420,6 +452,8 @@ struct kvm_vm *__vm_create(struct vm_shape shape, uint32_t nr_runnable_vcpus, 
	struct kvm_vm *vm;

	int i;



	kvm_set_files_rlimit(nr_runnable_vcpus);



	pr_debug("%s: mode='%s' type='%d', pages='%ld'\n", __func__,

		 vm_guest_mode_string(shape.mode), shape.type, nr_pages);