On 2020-01-15 02:49, Shaokun Zhang wrote:
Hi Marc, [This is from Nianyao]
On 2019/12/24 19:10, Marc Zyngier wrote:
In order to let a guest buy in the new, active-less SGIs, we
need to be able to switch between the two modes.
Handle this by stopping all guest activity, transfer the state
from one mode to the other, and resume the guest.
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
include/kvm/arm_vgic.h | 3 ++
virt/kvm/arm/vgic/vgic-v3.c | 2 +
virt/kvm/arm/vgic/vgic-v4.c | 96
+++++++++++++++++++++++++++++++++++++
virt/kvm/arm/vgic/vgic.h | 1 +
4 files changed, 102 insertions(+)
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 63457908c9c4..69f4164d6477 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -231,6 +231,9 @@ struct vgic_dist {
/* distributor enabled */
bool enabled;
+ /* Wants SGIs without active state */
+ bool nassgireq;
+
struct vgic_irq *spis;
struct vgic_io_device dist_iodev;
diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index c2fdea201747..c79a251c4974 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -540,6 +540,8 @@ int vgic_v3_map_resources(struct kvm *kvm)
goto out;
}
+ if (kvm_vgic_global_state.has_gicv4_1)
+ vgic_v4_configure_vsgis(kvm);
dist->ready = true;
out:
diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c
index c2fcde104ea2..063785fd2dc7 100644
--- a/virt/kvm/arm/vgic/vgic-v4.c
+++ b/virt/kvm/arm/vgic/vgic-v4.c
@@ -97,6 +97,102 @@ static irqreturn_t vgic_v4_doorbell_handler(int
irq, void *info)
return IRQ_HANDLED;
}
+static void vgic_v4_sync_sgi_config(struct its_vpe *vpe, struct
vgic_irq *irq)
+{
+ vpe->sgi_config[irq->intid].enabled = irq->enabled;
+ vpe->sgi_config[irq->intid].group = irq->group;
+ vpe->sgi_config[irq->intid].priority = irq->priority;
+}
+
+static void vgic_v4_enable_vsgis(struct kvm_vcpu *vcpu)
+{
+ struct its_vpe *vpe = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe;
+ int i;
+
+ /*
+ * With GICv4.1, every virtual SGI can be directly injected. So
+ * let's pretend that they are HW interrupts, tied to a host
+ * IRQ. The SGI code will do its magic.
+ */
+ for (i = 0; i < VGIC_NR_SGIS; i++) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, i);
+ struct irq_desc *desc;
+ int ret;
+
+ if (irq->hw) {
+ vgic_put_irq(vcpu->kvm, irq);
+ continue;
+ }
+
+ irq->hw = true;
+ irq->host_irq = irq_find_mapping(vpe->sgi_domain, i);
I think we need to check whether irq_find_mapping returns 0.
Why? its_alloc_vcpu_sgis() performs the allocation of all 16 SGIs
in one go. If that fails, we should error out. Conversely, we're
guaranteed that we have a mapping if it hasn't failed.
+ vgic_v4_sync_sgi_config(vpe, irq);
+ /*
+ * SGIs are initialised as disabled. Enable them if
+ * required by the rest of the VGIC init code.
+ */
+ desc = irq_to_desc(irq->host_irq);
+ ret = irq_domain_activate_irq(irq_desc_get_irq_data(desc),
+ false);
If irq->host_irq is not valid , in irq_domain_activate_irq, it will
trigger NULL pointer dereference in host kernel.
I meet a problem here. When hw support GIC4.1, and host kernel is
started with
kvm-arm.vgic_v4_enable=0, starting a virtual machine will trigger NULL
pointer
dereference in host. The following is error info:
[...]
But the problem here is that we're trying to use GICv4.1 even if GICv4
is disabled. I don't think there is a point in trying to sidestep this
locally if we're doing the wrong thing at top-level, which seems to be
the case.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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