This error was reported by valgrind when running qemu-system-x86_64 with kvm: ==975== Conditional jump or move depends on uninitialised value(s) ==975== at 0x521C38: cpuid_find_entry (kvm.c:176) ==975== by 0x5235BA: kvm_arch_init_vcpu (kvm.c:686) ==975== by 0x4D5175: kvm_init_vcpu (kvm-all.c:267) ==975== by 0x45035B: qemu_kvm_cpu_thread_fn (cpus.c:858) ==975== by 0xD361E0D: start_thread (pthread_create.c:311) ==975== by 0xD65E9EC: clone (clone.S:113) ==975== Uninitialised value was created by a stack allocation ==975== at 0x5226E4: kvm_arch_init_vcpu (kvm.c:446) Instead of adding more memset calls for parts of cpuid_data, the existing calls were removed and cpuid_data is now initialized completely in one call. Signed-off-by: Stefan Weil <sw@xxxxxxxxxxx> --- I did not check whether older versions also need this fix. Stefan W. target-i386/kvm.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/target-i386/kvm.c b/target-i386/kvm.c index 749aa09..3ffd3e0 100644 --- a/target-i386/kvm.c +++ b/target-i386/kvm.c @@ -456,11 +456,12 @@ int kvm_arch_init_vcpu(CPUState *cs) uint32_t signature[3]; int r; + memset(&cpuid_data, 0, sizeof(cpuid_data)); + cpuid_i = 0; /* Paravirtualization CPUIDs */ c = &cpuid_data.entries[cpuid_i++]; - memset(c, 0, sizeof(*c)); c->function = KVM_CPUID_SIGNATURE; if (!hyperv_enabled(cpu)) { memcpy(signature, "KVMKVMKVM\0\0\0", 12); @@ -474,7 +475,6 @@ int kvm_arch_init_vcpu(CPUState *cs) c->edx = signature[2]; c = &cpuid_data.entries[cpuid_i++]; - memset(c, 0, sizeof(*c)); c->function = KVM_CPUID_FEATURES; c->eax = env->features[FEAT_KVM]; @@ -483,13 +483,11 @@ int kvm_arch_init_vcpu(CPUState *cs) c->eax = signature[0]; c = &cpuid_data.entries[cpuid_i++]; - memset(c, 0, sizeof(*c)); c->function = HYPERV_CPUID_VERSION; c->eax = 0x00001bbc; c->ebx = 0x00060001; c = &cpuid_data.entries[cpuid_i++]; - memset(c, 0, sizeof(*c)); c->function = HYPERV_CPUID_FEATURES; if (cpu->hyperv_relaxed_timing) { c->eax |= HV_X64_MSR_HYPERCALL_AVAILABLE; @@ -500,7 +498,6 @@ int kvm_arch_init_vcpu(CPUState *cs) } c = &cpuid_data.entries[cpuid_i++]; - memset(c, 0, sizeof(*c)); c->function = HYPERV_CPUID_ENLIGHTMENT_INFO; if (cpu->hyperv_relaxed_timing) { c->eax |= HV_X64_RELAXED_TIMING_RECOMMENDED; @@ -511,13 +508,11 @@ int kvm_arch_init_vcpu(CPUState *cs) c->ebx = cpu->hyperv_spinlock_attempts; c = &cpuid_data.entries[cpuid_i++]; - memset(c, 0, sizeof(*c)); c->function = HYPERV_CPUID_IMPLEMENT_LIMITS; c->eax = 0x40; c->ebx = 0x40; c = &cpuid_data.entries[cpuid_i++]; - memset(c, 0, sizeof(*c)); c->function = KVM_CPUID_SIGNATURE_NEXT; memcpy(signature, "KVMKVMKVM\0\0\0", 12); c->eax = 0; -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html