Messages in this thread | | | Subject | Re: [PATCH] kvm: arm/arm64 : fix vm's hanging at startup time | From | Julien Thierry <> | Date | Thu, 15 Nov 2018 11:10:30 +0000 |
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On 15/11/18 10:22, peng.hao2@zte.com.cn wrote: >> Hi Peng, >> >> On 15/11/18 15:14, Peng Hao wrote: >>> When virtual machine starts, hang up. The kernel version of guest >>> is 4.16. Host support vgic_v3. >> >> I don't understand the issue here. the vgic_irq->group field does not >> exist in 4.16 (neither in the first nor the last version). Nor does the >> line you are modifying. > Guest's kernel version is 4.16 and Host's kernel version is mainline. > vgic_irq is a structure of Host's kvm. >> >> Both exist in mainline, but what you are mentioning shouldn't be an >> issue in mainline since vgic_irq->group gets initialized in >> kvm_vgic_vcpu_init for SGIs and PPIs (i.e. intid < 32) which includes >> your interrupt. > Initialization sequence of several components is like this; > 1. kvm_vgic_vcpu_init ---- here, dist is not initialized at this time. > and the value of irq->group depends on > dist->vgic_model. but now dist->vgic_model = 0 > and irq->group=0. > 2. vgic_create ----- assign to dist->vgic_model. > 3. kvm_vgic_dist_init >
I see, thanks for explaining.
This means the initialization in kvm_vgic_vcpu_init depends on whether userland creates the GIC device first or the vcpus first...
I don't think the issue lies in vgic_v3_populate_lr, but in kvm_vgic_vcpu_init which clearly expects dist->vgic_model to be initialized in two places. However, the comment at the top of vgic-init.c states:
* CPU Interface:
*
* - kvm_vgic_vcpu_init(): initialization of static data that
* doesn't depend on any sizing information or emulation type. No
* allocation is allowed there.
So I don't think we're supposed to check for dist->vgic_model here. Those two checks should probably be moved elsewhere (maybe in kvm_vgic_vcpu_enable?) once the gic type has been set.
Thanks,
> thanks. >> >> Cheers, >> >>> 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. >>> 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 <peng.hao2@zte.com.cn> >>> --- >>> 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) >>> val |= ICH_LR_GROUP; >>> >>> val |= (u64)irq->priority << ICH_LR_PRIORITY_SHIFT; >>> >> >> -- >> Julien Thierry
-- Julien Thierry
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