On Wed, Jun 29, 2022 at 8:07 AM Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> wrote:
>
> SECONDARY_EXEC_ENCLS_EXITING is conditionally added to the 'optional'
> checklist in setup_vmcs_config() but there's little value in doing so.
> First, as the control is optional, we can always check for its
> presence, no harm done. Second, the only real value cpu_has_sgx() check
> gives is that on the CPUs which support SECONDARY_EXEC_ENCLS_EXITING but
> don't support SGX, the control is not getting enabled. It's highly unlikely
> such CPUs exist but it's possible that some hypervisors expose broken vCPU
> models.
>
> Preserve cpu_has_sgx() check but filter the result of adjust_vmx_controls()
> instead of the input.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> ---
> arch/x86/kvm/vmx/vmx.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 89a3bbafa5af..e32d91006b80 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -2528,9 +2528,9 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,
> SECONDARY_EXEC_PT_CONCEAL_VMX |
> SECONDARY_EXEC_ENABLE_VMFUNC |
> SECONDARY_EXEC_BUS_LOCK_DETECTION |
> - SECONDARY_EXEC_NOTIFY_VM_EXITING;
> - if (cpu_has_sgx())
> - opt2 |= SECONDARY_EXEC_ENCLS_EXITING;
> + SECONDARY_EXEC_NOTIFY_VM_EXITING |
> + SECONDARY_EXEC_ENCLS_EXITING;
> +
> if (adjust_vmx_controls(min2, opt2,
> MSR_IA32_VMX_PROCBASED_CTLS2,
> &_cpu_based_2nd_exec_control) < 0)
> @@ -2577,6 +2577,9 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,
> vmx_cap->vpid = 0;
> }
>
> + if (!cpu_has_sgx())
> + _cpu_based_2nd_exec_control &= ~SECONDARY_EXEC_ENCLS_EXITING;
NYC, but why is there a leading underscore here?
> if (_cpu_based_exec_control & CPU_BASED_ACTIVATE_TERTIARY_CONTROLS) {
> u64 opt3 = TERTIARY_EXEC_IPI_VIRT;
>
> --
> 2.35.3
>
Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>
