On Thu, Mar 04, 2021, Yang Weijiang wrote:
> @@ -3375,6 +3391,12 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
> if (kvm_mpx_supported() &&
> !(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS))
> vmx->nested.vmcs01_guest_bndcfgs = vmcs_read64(GUEST_BNDCFGS);
> + if (kvm_cet_supported() &&
> + !(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_CET_STATE)) {
Alignment.
> + vmx->nested.vmcs01_guest_ssp = vmcs_readl(GUEST_SSP);
> + vmx->nested.vmcs01_guest_s_cet = vmcs_readl(GUEST_S_CET);
> + vmx->nested.vmcs01_guest_ssp_tbl = vmcs_readl(GUEST_INTR_SSP_TABLE);
> + }
>
> /*
> * Overwrite vmcs01.GUEST_CR3 with L1's CR3 if EPT is disabled *and*
> @@ -4001,6 +4023,9 @@ static bool is_vmcs12_ext_field(unsigned long field)
> case GUEST_IDTR_BASE:
> case GUEST_PENDING_DBG_EXCEPTIONS:
> case GUEST_BNDCFGS:
> + case GUEST_SSP:
> + case GUEST_INTR_SSP_TABLE:
> + case GUEST_S_CET:
> return true;
> default:
> break;
> @@ -4052,6 +4077,11 @@ static void sync_vmcs02_to_vmcs12_rare(struct kvm_vcpu *vcpu,
> vmcs_readl(GUEST_PENDING_DBG_EXCEPTIONS);
> if (kvm_mpx_supported())
> vmcs12->guest_bndcfgs = vmcs_read64(GUEST_BNDCFGS);
> + if (kvm_cet_supported()) {
Isn't the existing kvm_mpx_supported() check wrong in the sense that KVM only
needs to sync to vmcs12 if KVM and the guest both support MPX? Same would
apply to CET. Not sure it'd be a net positive in terms of performance since
guest_cpuid_has() can be quite slow, but overwriting vmcs12 fields that
technically don't exist feels wrong.
> + vmcs12->guest_ssp = vmcs_readl(GUEST_SSP);
> + vmcs12->guest_s_cet = vmcs_readl(GUEST_S_CET);
> + vmcs12->guest_ssp_tbl = vmcs_readl(GUEST_INTR_SSP_TABLE);
> + }
>
> vmx->nested.need_sync_vmcs02_to_vmcs12_rare = false;
> }
> diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
> index 9d3a557949ac..36dc4fdb0909 100644
> --- a/arch/x86/kvm/vmx/vmx.h
> +++ b/arch/x86/kvm/vmx/vmx.h
> @@ -155,6 +155,9 @@ struct nested_vmx {
> /* to migrate it to L2 if VM_ENTRY_LOAD_DEBUG_CONTROLS is off */
> u64 vmcs01_debugctl;
> u64 vmcs01_guest_bndcfgs;
> + u64 vmcs01_guest_ssp;
> + u64 vmcs01_guest_s_cet;
> + u64 vmcs01_guest_ssp_tbl;
>
> /* to migrate it to L1 if L2 writes to L1's CR8 directly */
> int l1_tpr_threshold;
> --
> 2.26.2
>
