Instead of silently changing the number of banks in mcg_cap based on kvm_get_mce_cap_supported(), abort initialization if the host doesn't support MCE_BANKS_DEF banks. Note that MCE_BANKS_DEF was always 10 since it was introduced in QEMU, and Linux always returned 32 at KVM_CAP_MCE since KVM_CAP_MCE was introduced, so no behavior is being changed and the error can't be triggered by any Linux version. The point of the new check is to ensure we won't silently change the bank count if we change MCE_BANKS_DEF or make the bank count configurable in the future. Signed-off-by: Eduardo Habkost <ehabkost@xxxxxxxxxx> --- target-i386/kvm.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/target-i386/kvm.c b/target-i386/kvm.c index 2a9953b..ee7bc69 100644 --- a/target-i386/kvm.c +++ b/target-i386/kvm.c @@ -784,11 +784,14 @@ int kvm_arch_init_vcpu(CPUState *cs) return ret; } - if (banks > MCE_BANKS_DEF) { - banks = MCE_BANKS_DEF; + if (MCE_BANKS_DEF > banks) { + error_report("kvm: Unsupported MCE bank count: %d > %d\n", + MCE_BANKS_DEF, banks); + return -ENOTSUP; } + mcg_cap &= MCE_CAP_DEF; - mcg_cap |= banks; + mcg_cap |= MCE_BANKS_DEF; ret = kvm_vcpu_ioctl(cs, KVM_X86_SETUP_MCE, &mcg_cap); if (ret < 0) { fprintf(stderr, "KVM_X86_SETUP_MCE: %s", strerror(-ret)); -- 2.1.0 -- 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