* [PATCH MANUALSEL 5.4 2/2] KVM: selftests: Make sure kvm_create_max_vcpus test won't hit RLIMIT_NOFILE [not found] <20211213142028.352438-1-sashal@kernel.org> @ 2021-12-13 14:20 ` Sasha Levin 2021-12-13 14:22 ` Paolo Bonzini 0 siblings, 1 reply; 2+ messages in thread From: Sasha Levin @ 2021-12-13 14:20 UTC (permalink / raw) To: linux-kernel, stable Cc: Vitaly Kuznetsov, Sean Christopherson, Paolo Bonzini, Sasha Levin, shuah, kvm, linux-kselftest From: Vitaly Kuznetsov <vkuznets@redhat.com> [ Upstream commit 908fa88e420f30dde6d80f092795a18ec72ca6d3 ] With the elevated 'KVM_CAP_MAX_VCPUS' value kvm_create_max_vcpus test may hit RLIMIT_NOFILE limits: # ./kvm_create_max_vcpus KVM_CAP_MAX_VCPU_ID: 4096 KVM_CAP_MAX_VCPUS: 1024 Testing creating 1024 vCPUs, with IDs 0...1023. /dev/kvm not available (errno: 24), skipping test Adjust RLIMIT_NOFILE limits to make sure KVM_CAP_MAX_VCPUS fds can be opened. Note, raising hard limit ('rlim_max') requires CAP_SYS_RESOURCE capability which is generally not needed to run kvm selftests (but without raising the limit the test is doomed to fail anyway). Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20211123135953.667434-1-vkuznets@redhat.com> [Skip the test if the hard limit can be raised. - Paolo] Reviewed-by: Sean Christopherson <seanjc@google.com> Tested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- .../selftests/kvm/kvm_create_max_vcpus.c | 30 +++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/tools/testing/selftests/kvm/kvm_create_max_vcpus.c b/tools/testing/selftests/kvm/kvm_create_max_vcpus.c index 231d79e57774e..cfe75536d8a55 100644 --- a/tools/testing/selftests/kvm/kvm_create_max_vcpus.c +++ b/tools/testing/selftests/kvm/kvm_create_max_vcpus.c @@ -12,6 +12,7 @@ #include <stdio.h> #include <stdlib.h> #include <string.h> +#include <sys/resource.h> #include "test_util.h" @@ -43,10 +44,39 @@ 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; printf("KVM_CAP_MAX_VCPU_ID: %d\n", kvm_max_vcpu_id); printf("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); + if (r < 0) { + printf("RLIMIT_NOFILE hard limit is too low (%d, wanted %d)\n", + old_rlim_max, nr_fds_wanted); + exit(KSFT_SKIP); + } + } else { + TEST_ASSERT(!setrlimit(RLIMIT_NOFILE, &rl), "setrlimit() failed!"); + } + } + /* * Upstream KVM prior to 4.8 does not support KVM_CAP_MAX_VCPU_ID. * Userspace is supposed to use KVM_CAP_MAX_VCPUS as the maximum ID -- 2.33.0 ^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH MANUALSEL 5.4 2/2] KVM: selftests: Make sure kvm_create_max_vcpus test won't hit RLIMIT_NOFILE 2021-12-13 14:20 ` [PATCH MANUALSEL 5.4 2/2] KVM: selftests: Make sure kvm_create_max_vcpus test won't hit RLIMIT_NOFILE Sasha Levin @ 2021-12-13 14:22 ` Paolo Bonzini 0 siblings, 0 replies; 2+ messages in thread From: Paolo Bonzini @ 2021-12-13 14:22 UTC (permalink / raw) To: Sasha Levin, linux-kernel, stable Cc: Vitaly Kuznetsov, Sean Christopherson, shuah, kvm, linux-kselftest On 12/13/21 15:20, Sasha Levin wrote: > From: Vitaly Kuznetsov <vkuznets@redhat.com> > > [ Upstream commit 908fa88e420f30dde6d80f092795a18ec72ca6d3 ] > > With the elevated 'KVM_CAP_MAX_VCPUS' value kvm_create_max_vcpus test > may hit RLIMIT_NOFILE limits: > > # ./kvm_create_max_vcpus > KVM_CAP_MAX_VCPU_ID: 4096 > KVM_CAP_MAX_VCPUS: 1024 > Testing creating 1024 vCPUs, with IDs 0...1023. > /dev/kvm not available (errno: 24), skipping test > > Adjust RLIMIT_NOFILE limits to make sure KVM_CAP_MAX_VCPUS fds can be > opened. Note, raising hard limit ('rlim_max') requires CAP_SYS_RESOURCE > capability which is generally not needed to run kvm selftests (but without > raising the limit the test is doomed to fail anyway). > > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> > Message-Id: <20211123135953.667434-1-vkuznets@redhat.com> > [Skip the test if the hard limit can be raised. - Paolo] > Reviewed-by: Sean Christopherson <seanjc@google.com> > Tested-by: Sean Christopherson <seanjc@google.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > Signed-off-by: Sasha Levin <sashal@kernel.org> > --- > .../selftests/kvm/kvm_create_max_vcpus.c | 30 +++++++++++++++++++ > 1 file changed, 30 insertions(+) > > diff --git a/tools/testing/selftests/kvm/kvm_create_max_vcpus.c b/tools/testing/selftests/kvm/kvm_create_max_vcpus.c > index 231d79e57774e..cfe75536d8a55 100644 > --- a/tools/testing/selftests/kvm/kvm_create_max_vcpus.c > +++ b/tools/testing/selftests/kvm/kvm_create_max_vcpus.c > @@ -12,6 +12,7 @@ > #include <stdio.h> > #include <stdlib.h> > #include <string.h> > +#include <sys/resource.h> > > #include "test_util.h" > > @@ -43,10 +44,39 @@ 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; > > printf("KVM_CAP_MAX_VCPU_ID: %d\n", kvm_max_vcpu_id); > printf("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); > + if (r < 0) { > + printf("RLIMIT_NOFILE hard limit is too low (%d, wanted %d)\n", > + old_rlim_max, nr_fds_wanted); > + exit(KSFT_SKIP); > + } > + } else { > + TEST_ASSERT(!setrlimit(RLIMIT_NOFILE, &rl), "setrlimit() failed!"); > + } > + } > + > /* > * Upstream KVM prior to 4.8 does not support KVM_CAP_MAX_VCPU_ID. > * Userspace is supposed to use KVM_CAP_MAX_VCPUS as the maximum ID > Acked-by: Paolo Bonzini <pbonzini@redhat.com> ^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-12-13 14:20 ` [PATCH MANUALSEL 5.4 2/2] KVM: selftests: Make sure kvm_create_max_vcpus test won't hit RLIMIT_NOFILE Sasha Levin
2021-12-13 14:22 ` Paolo Bonzini
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