+Peter, +Jason (intel-iommu maintainer/reviewer)
On 15/07/2023 16:22, Bui Quang Minh wrote:
> As userspace APIC now supports x2APIC, intel interrupt remapping
> hardware can be set to EIM mode when userspace local APIC is used.
>
> Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
> Signed-off-by: Bui Quang Minh <minhquangbu...@gmail.com>
> ---
> hw/i386/intel_iommu.c | 11 -----------
> 1 file changed, 11 deletions(-)
>
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index dcc334060c..5e576f6059 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -4043,17 +4043,6 @@ static bool vtd_decide_config(IntelIOMMUState *s,
> Error **errp)
> && x86_iommu_ir_supported(x86_iommu) ?
> ON_OFF_AUTO_ON :
> ON_OFF_AUTO_OFF;
> }
> - if (s->intr_eim == ON_OFF_AUTO_ON && !s->buggy_eim) {
> - 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;
> - }
> - }
>
Given commit 20ca47429e ('Revert "intel_iommu: Fix irqchip / X2APIC
configuration checks"'), won't we regress behaviour again for the accel=kvm
case by dropping the kvm_enable_x2apic() call here?
Perhaps if we support userspace APIC with TCG the check just needs to be redone
to instead avoid always requiring kvm e.g.:
if (kvm_irqchip_in_kernel()) {
error_setg(errp, "eim=on requires accel=kvm,kernel-irqchip=split"
"(X2APIC_API, first shipped in v4.7)");
}
if (kvm_irqchip_is_split() && !kvm_enable_x2apic()) {
error_setg(errp, "eim=on requires support on the KVM side"
"(X2APIC_API, first shipped in v4.7)");
return false;
}
