[PATCH 53/59] KVM: arm64: nv: Implement maintenance interrupt forwarding

Marc Zyngier
2019-06-21T09:40:47Z

When we take a maintenance interrupt, we need to decide whether
it is generated on an action from the guest, or if it is something
that needs to be forwarded to the guest hypervisor.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/kvm/nested.c | 2 +-
virt/kvm/arm/vgic/vgic-init.c | 30 ++++++++++++++++++++++++++++++
virt/kvm/arm/vgic/vgic-v3-nested.c | 25 +++++++++++++++++++++----
3 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c
index df2db9ab7cfb..ab61f0f30ee6 100644
--- a/arch/arm64/kvm/nested.c
+++ b/arch/arm64/kvm/nested.c
@@ -545,7 +545,7 @@ bool vgic_state_is_nested(struct kvm_vcpu *vcpu)
bool imo = __vcpu_sys_reg(vcpu, HCR_EL2) & HCR_IMO;
bool fmo = __vcpu_sys_reg(vcpu, HCR_EL2) & HCR_FMO;

- WARN(imo != fmo, "Separate virtual IRQ/FIQ settings not supported\n");
+ WARN_ONCE(imo != fmo, "Separate virtual IRQ/FIQ settings not supported\n");

return nested_virt_in_use(vcpu) && imo && fmo && !is_hyp_ctxt(vcpu);
}
diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index 3bdb31eaed64..ec54bc8d5126 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -17,9 +17,11 @@
#include <linux/uaccess.h>
#include <linux/interrupt.h>
#include <linux/cpu.h>
+#include <linux/irq.h>
#include <linux/kvm_host.h>
#include <kvm/arm_vgic.h>
#include <asm/kvm_mmu.h>
+#include <asm/kvm_nested.h>
#include "vgic.h"

/*
@@ -240,6 +242,16 @@ int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
if (!irqchip_in_kernel(vcpu->kvm))
return 0;

+ if (nested_virt_in_use(vcpu)) {
+ /* FIXME: remove this hack */
+ if (vcpu->kvm->arch.vgic.maint_irq == 0)
+ vcpu->kvm->arch.vgic.maint_irq = kvm_vgic_global_state.maint_irq;
+ ret = kvm_vgic_set_owner(vcpu, vcpu->kvm->arch.vgic.maint_irq,
+ vcpu);
+ if (ret)
+ return ret;
+ }
+
/*
* If we are creating a VCPU with a GICv3 we must also register the
* KVM io device for the redistributor that belongs to this VCPU.
@@ -455,12 +467,23 @@ static int vgic_init_cpu_dying(unsigned int cpu)

static irqreturn_t vgic_maintenance_handler(int irq, void *data)
{
+ struct kvm_vcpu *vcpu = *(struct kvm_vcpu **)data;
+
/*
* We cannot rely on the vgic maintenance interrupt to be
* delivered synchronously. This means we can only use it to
* exit the VM, and we perform the handling of EOIed
* interrupts on the exit path (see vgic_fold_lr_state).
*/
+
+ /* If not nested, deactivate */
+ if (!vcpu || !vgic_state_is_nested(vcpu)) {
+ irq_set_irqchip_state(irq, IRQCHIP_STATE_ACTIVE, false);
+ return IRQ_HANDLED;
+ }
+
+ /* Assume nested from now */
+ vgic_v3_handle_nested_maint_irq(vcpu);
return IRQ_HANDLED;
}

@@ -531,6 +554,13 @@ int kvm_vgic_hyp_init(void)
return ret;
}

+ ret = irq_set_vcpu_affinity(kvm_vgic_global_state.maint_irq,
+ kvm_get_running_vcpus());
+ if (ret) {
+ kvm_err("Error setting vcpu affinity\n");
+ goto out_free_irq;
+ }
+
ret = cpuhp_setup_state(CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
"kvm/arm/vgic:starting",
vgic_init_cpu_starting, vgic_init_cpu_dying);
diff --git a/virt/kvm/arm/vgic/vgic-v3-nested.c b/virt/kvm/arm/vgic/vgic-v3-nested.c
index c917d49e4a14..7c5f82ae68e0 100644
--- a/virt/kvm/arm/vgic/vgic-v3-nested.c
+++ b/virt/kvm/arm/vgic/vgic-v3-nested.c
@@ -172,10 +172,20 @@ void vgic_v3_sync_nested(struct kvm_vcpu *vcpu)
void vgic_v3_load_nested(struct kvm_vcpu *vcpu)
{
struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+ struct vgic_irq *irq;
+ unsigned long flags;

vgic_cpu->shadow_vgic_v3 = vgic_cpu->nested_vgic_v3;
vgic_v3_create_shadow_lr(vcpu);
__vgic_v3_restore_state(vcpu_shadow_if(vcpu));
+
+ irq = vgic_get_irq(vcpu->kvm, vcpu, vcpu->kvm->arch.vgic.maint_irq);
+ raw_spin_lock_irqsave(&irq->irq_lock, flags);
+ if (irq->line_level || irq->active)
+ irq_set_irqchip_state(kvm_vgic_global_state.maint_irq,
+ IRQCHIP_STATE_ACTIVE, true);
+ raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
+ vgic_put_irq(vcpu->kvm, irq);
}

void vgic_v3_put_nested(struct kvm_vcpu *vcpu)
@@ -190,11 +200,14 @@ void vgic_v3_put_nested(struct kvm_vcpu *vcpu)
*/
vgic_v3_fixup_shadow_lr_state(vcpu);
vgic_cpu->nested_vgic_v3 = vgic_cpu->shadow_vgic_v3;
+ irq_set_irqchip_state(kvm_vgic_global_state.maint_irq,
+ IRQCHIP_STATE_ACTIVE, false);
}

void vgic_v3_handle_nested_maint_irq(struct kvm_vcpu *vcpu)
{
struct vgic_v3_cpu_if *cpu_if = vcpu_nested_if(vcpu);
+ bool state;

/*
* If we exit a nested VM with a pending maintenance interrupt from the
@@ -202,8 +215,12 @@ void vgic_v3_handle_nested_maint_irq(struct kvm_vcpu *vcpu)
* can re-sync the appropriate LRs and sample level triggered interrupts
* again.
*/
- if (vgic_state_is_nested(vcpu) &&
- (cpu_if->vgic_hcr & ICH_HCR_EN) &&
- vgic_v3_get_misr(vcpu))
- kvm_inject_nested_irq(vcpu);
+ if (!vgic_state_is_nested(vcpu))
+ return;
+
+ state = cpu_if->vgic_hcr & ICH_HCR_EN;
+ state &= vgic_v3_get_misr(vcpu);
+
+ kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
+ vcpu->kvm->arch.vgic.maint_irq, state, vcpu);
}
--
2.20.1