On Mon, May 17, 2021 at 2:26 PM Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
>
> On Mon, May 17, 2021, Jim Mattson wrote:
> > On Mon, May 17, 2021 at 2:03 PM Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
> > >
> > > On Thu, May 13, 2021, Vitaly Kuznetsov wrote:
> > > > Currently, APICv/AVIC enablement is global ('enable_apicv' module parameter
> > > > for Intel, 'avic' module parameter for AMD) but there's no way to check
> > > > it from vendor-neutral code. Add 'apicv_supported()' to kvm_x86_ops and
> > > > invert kvm_apicv_init() (which now doesn't need to be called from arch-
> > > > specific code).
> > >
> > > Rather than add a new hook, just move the variable to x86.c, and export it so
> > > that VMX and SVM can give it different module names. The only hiccup is that
> > > avic is off by default, but I don't see why that can't be changed.
> >
> > See https://www.spinics.net/lists/kvm/msg208722.html.
>
> Boo. A common enable_apicv can still work, SVM just needs an intermediary
> between the module param and enable_apicv.
>
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -185,6 +185,10 @@ module_param(vls, int, 0444);
> static int vgif = true;
> module_param(vgif, int, 0444);
>
> +/* enable / disable AVIC */
> +static bool avic;
> +module_param(avic, bool, S_IRUGO);
> +
> bool __read_mostly dump_invalid_vmcb;
> module_param(dump_invalid_vmcb, bool, 0644);
>
> @@ -1009,16 +1013,19 @@ static __init int svm_hardware_setup(void)
> nrips = false;
> }
>
> - if (avic) {
> - if (!npt_enabled ||
> - !boot_cpu_has(X86_FEATURE_AVIC) ||
> - !IS_ENABLED(CONFIG_X86_LOCAL_APIC)) {
> - avic = false;
> - } else {
> - pr_info("AVIC enabled\n");
> + if (!npt_enabled || !boot_cpu_has(X86_FEATURE_AVIC))
> + avic = false;
>
> - amd_iommu_register_ga_log_notifier(&avic_ga_log_notifier);
> - }
> + /*
> + * Override the common enable_apicv. AVIC is disabled by default
> + * because Jim said so.
> + */
Hey! I'm just the messenger. Wei Huang said so.
> + enable_apicv = avic;
> +
> + if (enable_apicv) {
> + pr_info("AVIC enabled\n");
> +
> + amd_iommu_register_ga_log_notifier(&avic_ga_log_notifier);
> }
>
> if (vls) {
