Re: [PATCH v6 3/7] KVM: nVMX: Move guest non-reg state checks to VM-Exit path

[Krish Sadhukhan <krish.sadhukhan@oracle.com>]

On 04/11/2019 12:18 PM, Sean Christopherson wrote:
> Per Intel's SDM, volume 3, section Checking and Loading Guest State:
>
>    Because the checking and the loading occur concurrently, a failure may
>    be discovered only after some state has been loaded. For this reason,
>    the logical processor responds to such failures by loading state from
>    the host-state area, as it would for a VM exit.
>
> In other words, a failed non-register state consistency check results in
> a VM-Exit, not VM-Fail.  Moving the non-reg state checks also paves the
> way for renaming nested_vmx_check_vmentry_postreqs() to align with the
> SDM, i.e. nested_vmx_check_vmentry_guest_state().
>
> Fixes: 26539bd0e446a ("KVM: nVMX: check vmcs12 for valid activity state")
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>   arch/x86/kvm/vmx/nested.c | 30 +++++++++++++++---------------
>   1 file changed, 15 insertions(+), 15 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index f487aae3233e..fe1323ab6894 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -2612,18 +2612,6 @@ static int nested_check_host_control_regs(struct kvm_vcpu *vcpu,
>   	return 0;
>   }
>   
> -/*
> - * Checks related to Guest Non-register State
> - */
> -static int nested_check_guest_non_reg_state(struct vmcs12 *vmcs12)
> -{
> -	if (vmcs12->guest_activity_state != GUEST_ACTIVITY_ACTIVE &&
> -	    vmcs12->guest_activity_state != GUEST_ACTIVITY_HLT)
> -		return -EINVAL;
> -
> -	return 0;
> -}
> -
>   static int nested_vmx_check_vmentry_prereqs(struct kvm_vcpu *vcpu,
>   					    struct vmcs12 *vmcs12)
>   {
> @@ -2635,9 +2623,6 @@ static int nested_vmx_check_vmentry_prereqs(struct kvm_vcpu *vcpu,
>   	if (nested_check_host_control_regs(vcpu, vmcs12))
>   		return VMXERR_ENTRY_INVALID_HOST_STATE_FIELD;
>   
> -	if (nested_check_guest_non_reg_state(vmcs12))
> -		return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
> -
>   	return 0;
>   }
>   
> @@ -2668,6 +2653,18 @@ static int nested_vmx_check_vmcs_link_ptr(struct kvm_vcpu *vcpu,
>   	return r;
>   }
>   
> +/*
> + * Checks related to Guest Non-register State
> + */
> +static int nested_check_guest_non_reg_state(struct vmcs12 *vmcs12)
> +{
> +	if (vmcs12->guest_activity_state != GUEST_ACTIVITY_ACTIVE &&
> +	    vmcs12->guest_activity_state != GUEST_ACTIVITY_HLT)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
>   static int nested_vmx_check_vmentry_postreqs(struct kvm_vcpu *vcpu,
>   					     struct vmcs12 *vmcs12,
>   					     u32 *exit_qual)
> @@ -2713,6 +2710,9 @@ static int nested_vmx_check_vmentry_postreqs(struct kvm_vcpu *vcpu,
>   		(vmcs12->guest_bndcfgs & MSR_IA32_BNDCFGS_RSVD)))
>   			return 1;
>   
> +	if (nested_check_guest_non_reg_state(vmcs12))
> +		return 1;
> +
>   	return 0;
>   }
>   

Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>