Since VMX and SVM both would never update the control bits if exits are disable after vCPUs are created, only allow setting exits disable flag before vCPU creation. Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> Signed-off-by: Kechen Lu <kechenl@xxxxxxxxxx> --- Documentation/virt/kvm/api.rst | 1 + arch/x86/kvm/x86.c | 6 ++++++ 2 files changed, 7 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index aeeb071c7688..d1c50b95bbc1 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6581,6 +6581,7 @@ branch to guests' 0x200 interrupt vector. :Architectures: x86 :Parameters: args[0] defines which exits are disabled :Returns: 0 on success, -EINVAL when args[0] contains invalid exits + or if any vCPU has already been created Valid bits in args[0] are:: diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0cf1082455df..37529c0c279d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5764,6 +5764,10 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, if (cap->args[0] & ~KVM_X86_DISABLE_VALID_EXITS) break; + mutex_lock(&kvm->lock); + if (kvm->created_vcpus) + goto disable_exits_unlock; + if ((cap->args[0] & KVM_X86_DISABLE_EXITS_MWAIT) && kvm_can_mwait_in_guest()) kvm->arch.mwait_in_guest = true; @@ -5774,6 +5778,8 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, if (cap->args[0] & KVM_X86_DISABLE_EXITS_CSTATE) kvm->arch.cstate_in_guest = true; r = 0; +disable_exits_unlock: + mutex_unlock(&kvm->lock); break; case KVM_CAP_MSR_PLATFORM_INFO: kvm->arch.guest_can_read_msr_platform_info = cap->args[0]; -- 2.30.2
