Re: [PATCH v3] x86/hyperv: Restrict get_vtl to only VTL platforms

From: Wei Liu
Date: Fri Sep 22 2023 - 14:42:43 EST


On Tue, Sep 19, 2023 at 09:04:35PM -0700, Saurabh Sengar wrote:
> When Linux runs in a non-default VTL (CONFIG_HYPERV_VTL_MODE=y),
> get_vtl() must never fail as its return value is used in negotiations
> with the host. In the more generic case, (CONFIG_HYPERV_VTL_MODE=n) the
> VTL is always zero so there's no need to do the hypercall.
>
> Make get_vtl() BUG() in case of failure and put the implementation under
> "if IS_ENABLED(CONFIG_HYPERV_VTL_MODE)" to avoid the call altogether in
> the most generic use case.
>
> Signed-off-by: Saurabh Sengar <ssengar@xxxxxxxxxxxxxxxxxxx>
> Reviewed-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>

Applied to hyperv-fixes. Thanks.