Re: [PATCH] kvm/vmx: Don't vmwrite to unsupported secondary processor controls

[Zdenek Kaspar <zkaspar82@xxxxxxxxx>]

On 07/10/2018 12:17 AM, Jim Mattson wrote:
> Older physical CPUs (and possibly some virtual CPUs) don't support the
> secondary processor-based VM-execution controls.
>
> Fixes: 8d860bbeedef ("kvm: vmx: Basic APIC virtualization controls have three settings")
> Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
> ---
>   arch/x86/kvm/vmx.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 1689f433f3a08..af68df0765067 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -9577,7 +9577,8 @@ static void vmx_set_virtual_apic_mode(struct kvm_vcpu *vcpu)
>   				SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE;
>   		break;
>   	}
> -	vmcs_write32(SECONDARY_VM_EXEC_CONTROL, sec_exec_control);
> +	if (cpu_has_secondary_exec_ctrls())
> +		vmcs_write32(SECONDARY_VM_EXEC_CONTROL, sec_exec_control);
>   
>   	vmx_update_msr_bitmap(vcpu);
>   }

Tested-by: Zdenek Kaspar <zkaspar82@xxxxxxxxx>