On 7/17/23 17:47, Joao Martins wrote:
+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;
}
Thank you for your review. I think the check for kvm_irqchip_in_kernel()
is not correct, AFAIK, kvm_irqchip_is_split() == true also means
kvm_irqchip_in_kernel() == true on x86. To check if kernel-irqchip = on,
we need to do something like in x86_iommu_realize
bool irq_all_kernel = kvm_irqchip_in_kernel() &&
!kvm_irqchip_is_split();
The original check for !kvm_irqchip_is_split means emulated/userspace
APIC. It's because to reach that check x86_iommu_ir_supported(...) ==
true and x86_iommu_ir_supported(...) == true is not supported when
kernel-irqchip = on (there is a check for this in x86_iommu_realize)
So I think we need to change the check to
if (s->intr_eim == ON_OFF_AUTO_ON && !s->buggy_eim) {
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;
}
}
Is it OK?
Thanks,
Quang Minh.
