Re: [PATCH 2/2] intel_iommu: Fix irqchip / X2APIC configuration checks

[Claudio Fontana]

Acked-by: Claudio Fontana <cfontana@suse.de>

I'll try to find time tonight to give you a tested by.

Ciao,

Claudio

On 11/30/21 2:42 PM, David Woodhouse wrote:
> We don't need to check kvm_enable_x2apic(). It's perfectly OK to support
> interrupt remapping even if we can't address CPUs above 254. Kind of
> pointless, but still functional.
> 
> The check on kvm_enable_x2apic() needs to happen *anyway* in order to
> allow CPUs above 254 even without an IOMMU, so allow that to happen
> elsewhere.
> 
> However, we do require the *split* irqchip in order to rewrite I/OAPIC
> destinations. So fix that check while we're here.
> 
> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
> ---
>  hw/i386/intel_iommu.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index 294499ee20..b0439d0fbf 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -3746,15 +3746,10 @@ static bool vtd_decide_config(IntelIOMMUState *s, 
> Error **errp)
>                                                ON_OFF_AUTO_ON : 
> ON_OFF_AUTO_OFF;
>      }
>      if (s->intr_eim == ON_OFF_AUTO_ON && !s->buggy_eim) {
> -        if (!kvm_irqchip_in_kernel()) {
> +        if (!kvm_irqchip_is_split()) {
>              error_setg(errp, "eim=on requires 
> accel=kvm,kernel-irqchip=split");
>              return false;
>          }
> -        if (!kvm_enable_x2apic()) {
> -            error_setg(errp, "eim=on requires support on the KVM side"
> -                             "(X2APIC_API, first shipped in v4.7)");
> -            return false;
> -        }
>      }
>  
>      /* Currently only address widths supported are 39 and 48 bits */
>