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

Krish Sadhukhan
2019-04-11T21:05:42Z

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>