On Mon, Oct 02, 2023, Tom Lendacky wrote:
> Commit 916e3e5f26ab ("KVM: SVM: Do not use user return MSR support for
> virtualized TSC_AUX") introduced a local variable used for the rdmsr()
> function for the high 32-bits of the MSR value. This variable is not used
> after being set and triggers a warning or error, when treating warnings
> as errors, when the unused-but-set-variable flag is set. Mark this
> variable as __maybe_unused to fix this.
>
> Fixes: 916e3e5f26ab ("KVM: SVM: Do not use user return MSR support for virtualized TSC_AUX")
> Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> ---
> arch/x86/kvm/svm/svm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 9507df93f410..4c917c74a4d3 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -691,7 +691,7 @@ static int svm_hardware_enable(void)
> */
> if (boot_cpu_has(X86_FEATURE_V_TSC_AUX)) {
> struct sev_es_save_area *hostsa;
> - u32 msr_hi;
> + u32 __maybe_unused msr_hi;
Argh, the abomination that is rdmsrl() strikes again :-/ We really should be able
to do:
hostsa->tsc_aux = (u32)rdmsrl(MSR_TSC_AUX);
I don't see a better quick fix than __maybe_unused though.
Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
