[PATCH v2 1/9] KVM: x86: check validity of argument to KVM_SET_MP_STATE

Paolo Bonzini
2022-08-11T21:06:47Z

An invalid argument to KVM_SET_MP_STATE has no effect other than making the
vCPU fail to run at the next KVM_RUN. Since it is extremely unlikely that
any userspace is relying on it, fail with -EINVAL just like for other
architectures.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/x86.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 132d662d9713..c44348bb6ef2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10653,7 +10653,8 @@ static inline int vcpu_block(struct kvm_vcpu *vcpu)
case KVM_MP_STATE_INIT_RECEIVED:
break;
default:
- return -EINTR;
+ WARN_ON(1);
+ break;
}
return 1;
}
@@ -11094,9 +11095,22 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,

vcpu_load(vcpu);

- if (!lapic_in_kernel(vcpu) &&
- mp_state->mp_state != KVM_MP_STATE_RUNNABLE)
+ switch (mp_state->mp_state) {
+ case KVM_MP_STATE_UNINITIALIZED:
+ case KVM_MP_STATE_HALTED:
+ case KVM_MP_STATE_AP_RESET_HOLD:
+ case KVM_MP_STATE_INIT_RECEIVED:
+ case KVM_MP_STATE_SIPI_RECEIVED:
+ if (!lapic_in_kernel(vcpu))
+ goto out;
+ break;
+
+ case KVM_MP_STATE_RUNNABLE:
+ break;
+
+ default:
goto out;
+ }

/*
* KVM_MP_STATE_INIT_RECEIVED means the processor is in
--
2.31.1