On Tue, 02 Apr 2019 09:22:29 +0100,
Auger Eric <eric.auger@xxxxxxxxxx> wrote:
>
> Hi Marc,
>
> On 4/2/19 9:24 AM, Marc Zyngier wrote:
> > When disabling LPIs (for example on reset) at the redistributor
> > level, it is expected that LPIs that was pending in the CPU
> > interface are eventually retired.
> >
> > Currently, this is not what is happening, and these LPIs will
> > stay in the ap_list, eventually being acknowledged by the vcpu
> > (which didn't quite expect this behaviour).
> >
> > The fix is thus to retire these LPIs from the list of pending
> > interrupts as we disable LPIs.
> >
> > Reported-by: Heyi Guo <guoheyi@xxxxxxxxxx>
> > Fixes: 0e4e82f154e3 ("KVM: arm64: vgic-its: Enable ITS emulation as a virtual MSI controller")
> > Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> > ---
> > Heyi,
> >
> > Can you please give this alternative patch a go on your setup?
> > This should be a much better fit than my original hack.
> >
> > Thanks,
> >
> > M.
> >
> > virt/kvm/arm/vgic/vgic-mmio-v3.c | 3 +++
> > virt/kvm/arm/vgic/vgic.c | 24 ++++++++++++++++++++++++
> > virt/kvm/arm/vgic/vgic.h | 1 +
> > 3 files changed, 28 insertions(+)
> >
> > diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> > index 4a12322bf7df..9f4843fe9cda 100644
> > --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
> > +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> > @@ -200,6 +200,9 @@ static void vgic_mmio_write_v3r_ctlr(struct kvm_vcpu *vcpu,
> >
> > vgic_cpu->lpis_enabled = val & GICR_CTLR_ENABLE_LPIS;
> >
> > + if (was_enabled && !vgic_cpu->lpis_enabled)
> > + vgic_flush_pending_lpis(vcpu);
> > +
> > if (!was_enabled && vgic_cpu->lpis_enabled)
> > vgic_enable_lpis(vcpu);
> > }
> > diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
> > index 3af69f2a3866..3f429cf2f694 100644
> > --- a/virt/kvm/arm/vgic/vgic.c
> > +++ b/virt/kvm/arm/vgic/vgic.c
> > @@ -151,6 +151,30 @@ void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq)
> > kfree(irq);
> > }
> >
> > +void vgic_flush_pending_lpis(struct kvm_vcpu *vcpu)
> > +{
> > + struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
> > + struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> > + struct vgic_irq *irq, *tmp;
> > + unsigned long flags;
> > +
> > + raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
> Do you need to hold the lpi_list_lock here as it is taken in vgic_put_irq.
You're right, this is absolutely silly, as it violates the rules at
the top of this very file. Don't write that kind of patches while
being severely jet-lagged. It should be better with this on top.
diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index 3f429cf2f694..191deccf60bf 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -153,13 +153,11 @@ void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq)
void vgic_flush_pending_lpis(struct kvm_vcpu *vcpu)
{
- struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
struct vgic_irq *irq, *tmp;
unsigned long flags;
- raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
- raw_spin_lock(&vgic_cpu->ap_list_lock);
+ raw_spin_lock_irqsave(&vgic_cpu->ap_list_lock, flags);
list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) {
if (irq->intid >= VGIC_MIN_LPI) {
@@ -171,8 +169,7 @@ void vgic_flush_pending_lpis(struct kvm_vcpu *vcpu)
}
}
- raw_spin_unlock(&vgic_cpu->ap_list_lock);
- raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
+ raw_spin_unlock_irqrestore(&vgic_cpu->ap_list_lock, flags);
}
void vgic_irq_set_phys_pending(struct vgic_irq *irq, bool pending)
> > + raw_spin_lock(&vgic_cpu->ap_list_lock);
> > +
> > + list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) {
> > + if (irq->intid >= VGIC_MIN_LPI) {
> > + raw_spin_lock(&irq->irq_lock);
> > + list_del(&irq->ap_list);
> > + irq->vcpu = NULL;
> > + raw_spin_unlock(&irq->irq_lock);
> > + vgic_put_irq(vcpu->kvm, irq);
> > + }
> > + }
> > +
> > + raw_spin_unlock(&vgic_cpu->ap_list_lock);
> > + raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
> A concern I have is how does this live with
> vgic_v3_save_pending_tables/its_sync_lpi_pending_table ctrl flow. I need
> to trace things.
It shouldn't change a thing. The only thing this patch tries to do is
to make sure that LPIs are not kept on the ap_list when they have been
turned off at the redistributor level. The pending bits are still
stored, and save/sync should work as expected (famous last words...).
Thanks,
M.
--
Jazz is not dead, it just smell funny.
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