On 12/13/21 15:19, 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 0299cd81b8ba2..aa3795cd7bd3d 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" @@ -40,10 +41,39 @@ 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;
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);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