The KVM_CREATE_VCPU ioctl ABI had an implicit integer truncation bug,
allowing 2^32 aliases for a vCPU ID by setting the upper 32 bits of a 64
bit ioctl() argument.
It also allowed excluding a once set boot CPU ID.
Verify this no longer works and gets rejected with an error.
Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
---
v3:
- test BOOT_CPU_ID interaction too
.../kvm/x86_64/max_vcpuid_cap_test.c | 22 +++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/kvm/x86_64/max_vcpuid_cap_test.c b/tools/testing/selftests/kvm/x86_64/max_vcpuid_cap_test.c
index 3cc4b86832fe..c2da915201be 100644
--- a/tools/testing/selftests/kvm/x86_64/max_vcpuid_cap_test.c
+++ b/tools/testing/selftests/kvm/x86_64/max_vcpuid_cap_test.c
@@ -26,19 +26,37 @@ int main(int argc, char *argv[])
TEST_ASSERT(ret < 0,
"Setting KVM_CAP_MAX_VCPU_ID beyond KVM cap should fail");
+ /* Test BOOT_CPU_ID interaction (MAX_VCPU_ID cannot be lower) */
+ if (kvm_has_cap(KVM_CAP_SET_BOOT_CPU_ID)) {
+ vm_ioctl(vm, KVM_SET_BOOT_CPU_ID, (void *)MAX_VCPU_ID);
+
+ /* Try setting KVM_CAP_MAX_VCPU_ID below BOOT_CPU_ID */
+ ret = __vm_enable_cap(vm, KVM_CAP_MAX_VCPU_ID, MAX_VCPU_ID - 1);
+ TEST_ASSERT(ret < 0,
+ "Setting KVM_CAP_MAX_VCPU_ID below BOOT_CPU_ID should fail");
+ }
+
/* Set KVM_CAP_MAX_VCPU_ID */
vm_enable_cap(vm, KVM_CAP_MAX_VCPU_ID, MAX_VCPU_ID);
-
/* Try to set KVM_CAP_MAX_VCPU_ID again */
ret = __vm_enable_cap(vm, KVM_CAP_MAX_VCPU_ID, MAX_VCPU_ID + 1);
TEST_ASSERT(ret < 0,
"Setting KVM_CAP_MAX_VCPU_ID multiple times should fail");
- /* Create vCPU with id beyond KVM_CAP_MAX_VCPU_ID cap*/
+ /* Create vCPU with id beyond KVM_CAP_MAX_VCPU_ID cap */
ret = __vm_ioctl(vm, KVM_CREATE_VCPU, (void *)MAX_VCPU_ID);
TEST_ASSERT(ret < 0, "Creating vCPU with ID > MAX_VCPU_ID should fail");
+ /* Create vCPU with id beyond UINT_MAX */
+ ret = __vm_ioctl(vm, KVM_CREATE_VCPU, (void *)(1L << 32));
+ TEST_ASSERT(ret < 0, "Creating vCPU with ID > UINT_MAX should fail");
+
+ /* Create vCPU with id within bounds */
+ ret = __vm_ioctl(vm, KVM_CREATE_VCPU, (void *)0);
+ TEST_ASSERT(ret >= 0, "Creating vCPU with ID 0 should succeed");
+
+ close(ret);
kvm_vm_free(vm);
return 0;
}
--
2.30.2
