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 <[email protected]>
---
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
On Thu, 2022-08-11 at 17:05 -0400, Paolo Bonzini wrote:
> 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 <[email protected]>
> ---
> 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);
Very small nitpick: Maybe WARN_ON_ONCE after all?
(but I don't see any way after this patch to have invalid mp_state)
> + 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
Reviewed-by: Maxim Levitsky <[email protected]>
Best regards,
Maxim Levitsky
On Mon, Aug 15, 2022, Maxim Levitsky wrote:
> On Thu, 2022-08-11 at 17:05 -0400, Paolo Bonzini wrote:
> > 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 <[email protected]>
> > ---
> > ?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);
>
> Very small nitpick: Maybe WARN_ON_ONCE after all??
+1, I don't think warning multiple times would help triage/debug, and this seems
like something that will fire a lot if it fires at all.