[PATCH] kvm: arm/arm64 : fix vm's hanging at startup time
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From: Andre Przywara <andre.przywara@arm.com>
Date: 2018-11-15 14:39:14
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On Thu, 15 Nov 2018 23:14:08 +0800 Peng Hao [off-list ref] wrote: Hi,
When virtual machine starts, hang up.
I take it you mean the *guest* hangs? Because it doesn't get a timer interrupt?
The kernel version of guest is 4.16. Host support vgic_v3.
Your host kernel is something recent, I guess?
It was mainly due to the incorrect vgic_irq's(intid=27) group value during injection interruption. when kvm_vgic_vcpu_init is called, dist is not initialized at this time. Unable to get vgic V3 or V2 correctly, so group is not set.
Mmh, that shouldn't happen with (v)GICv3. Do you use QEMU (which version?) or some other userland tool?
quoted hunk ↗ jump to hunk
group is setted to 1 when vgic_mmio_write_group is invoked at some time. when irq->group=0 (intid=27), No ICH_LR_GROUP flag was set and interrupt injection failed. Signed-off-by: Peng Hao <redacted> --- virt/kvm/arm/vgic/vgic-v3.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c index 9c0dd23..d101000 100644 --- a/virt/kvm/arm/vgic/vgic-v3.c +++ b/virt/kvm/arm/vgic/vgic-v3.c@@ -198,7 +198,7 @@ void vgic_v3_populate_lr(struct kvm_vcpu *vcpu,struct vgic_irq *irq, int lr) if (vgic_irq_is_mapped_level(irq) && (val & ICH_LR_PENDING_BIT)) irq->line_level = false; - if (irq->group) + if (model == KVM_DEV_TYPE_ARM_VGIC_V3)
This is not the right fix, not only because it basically reverts the GICv3 part of 87322099052 (KVM: arm/arm64: vgic: Signal IRQs using their configured group). Can you try to work out why kvm_vgic_vcpu_init() is apparently called before dist->vgic_model is set, also what value it has? If I understand the code correctly, that shouldn't happen for a GICv3. Cheers, Andre.
val |= ICH_LR_GROUP; val |= (u64)irq->priority << ICH_LR_PRIORITY_SHIFT;