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KVM: arm/arm64: vgic-new: Add IRQ sync/flush framework 

Implement the framework for syncing IRQs between our emulation and
the list registers, which represent the guest's view of IRQs.
This is done in kvm_vgic_flush_hwstate and kvm_vgic_sync_hwstate,
which gets called on guest entry and exit.
The code talking to the actual GICv2/v3 hardware is added in the
following patches.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
hifive-unleashed-5.1
Marc Zyngier 2015-11-26 17:19:25 +00:00 committed by Christoffer Dall
parent 8e44474579
commit 0919e84c0f
3 changed files with 198 additions and 0 deletions
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4
include/kvm/vgic/vgic.h
View File

@ -190,6 +190,10 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
#define vgic_valid_spi(k, i) (((i) >= VGIC_NR_PRIVATE_IRQS) && \
((i) < (k)->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS))
bool kvm_vcpu_has_pending_irqs(struct kvm_vcpu *vcpu);
void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu);
void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu);
/**
* kvm_vgic_get_max_vcpus - Get the maximum number of VCPUs allowed by HW
*

192
virt/kvm/arm/vgic/vgic.c
View File

@ -307,3 +307,195 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
{
return vgic_update_irq_pending(kvm, cpuid, intid, level, false);
}
/**
* vgic_prune_ap_list - Remove non-relevant interrupts from the list
*
* @vcpu: The VCPU pointer
*
* Go over the list of "interesting" interrupts, and prune those that we
* won't have to consider in the near future.
*/
static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
{
struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
struct vgic_irq *irq, *tmp;
retry:
spin_lock(&vgic_cpu->ap_list_lock);
list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) {
struct kvm_vcpu *target_vcpu, *vcpuA, *vcpuB;
spin_lock(&irq->irq_lock);
BUG_ON(vcpu != irq->vcpu);
target_vcpu = vgic_target_oracle(irq);
if (!target_vcpu) {
/*
* We don't need to process this interrupt any
* further, move it off the list.
*/
list_del(&irq->ap_list);
irq->vcpu = NULL;
spin_unlock(&irq->irq_lock);
continue;
}
if (target_vcpu == vcpu) {
/* We're on the right CPU */
spin_unlock(&irq->irq_lock);
continue;
}
/* This interrupt looks like it has to be migrated. */
spin_unlock(&irq->irq_lock);
spin_unlock(&vgic_cpu->ap_list_lock);
/*
* Ensure locking order by always locking the smallest
* ID first.
*/
if (vcpu->vcpu_id < target_vcpu->vcpu_id) {
vcpuA = vcpu;
vcpuB = target_vcpu;
} else {
vcpuA = target_vcpu;
vcpuB = vcpu;
}
spin_lock(&vcpuA->arch.vgic_cpu.ap_list_lock);
spin_lock_nested(&vcpuB->arch.vgic_cpu.ap_list_lock,
SINGLE_DEPTH_NESTING);
spin_lock(&irq->irq_lock);
/*
* If the affinity has been preserved, move the
* interrupt around. Otherwise, it means things have
* changed while the interrupt was unlocked, and we
* need to replay this.
*
* In all cases, we cannot trust the list not to have
* changed, so we restart from the beginning.
*/
if (target_vcpu == vgic_target_oracle(irq)) {
struct vgic_cpu *new_cpu = &target_vcpu->arch.vgic_cpu;
list_del(&irq->ap_list);
irq->vcpu = target_vcpu;
list_add_tail(&irq->ap_list, &new_cpu->ap_list_head);
}
spin_unlock(&irq->irq_lock);
spin_unlock(&vcpuB->arch.vgic_cpu.ap_list_lock);
spin_unlock(&vcpuA->arch.vgic_cpu.ap_list_lock);
goto retry;
}
spin_unlock(&vgic_cpu->ap_list_lock);
}
static inline void vgic_process_maintenance_interrupt(struct kvm_vcpu *vcpu)
{
}
static inline void vgic_fold_lr_state(struct kvm_vcpu *vcpu)
{
}
/* Requires the irq_lock to be held. */
static inline void vgic_populate_lr(struct kvm_vcpu *vcpu,
struct vgic_irq *irq, int lr)
{
DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&irq->irq_lock));
}
static inline void vgic_clear_lr(struct kvm_vcpu *vcpu, int lr)
{
}
static inline void vgic_set_underflow(struct kvm_vcpu *vcpu)
{
}
/* Requires the ap_list_lock to be held. */
static int compute_ap_list_depth(struct kvm_vcpu *vcpu)
{
struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
struct vgic_irq *irq;
int count = 0;
DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));
list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
spin_lock(&irq->irq_lock);
/* GICv2 SGIs can count for more than one... */
if (vgic_irq_is_sgi(irq->intid) && irq->source)
count += hweight8(irq->source);
else
count++;
spin_unlock(&irq->irq_lock);
}
return count;
}
/* Requires the VCPU's ap_list_lock to be held. */
static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)
{
struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
struct vgic_irq *irq;
int count = 0;
DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));
if (compute_ap_list_depth(vcpu) > kvm_vgic_global_state.nr_lr) {
vgic_set_underflow(vcpu);
vgic_sort_ap_list(vcpu);
}
list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
spin_lock(&irq->irq_lock);
if (unlikely(vgic_target_oracle(irq) != vcpu))
goto next;
/*
* If we get an SGI with multiple sources, try to get
* them in all at once.
*/
do {
vgic_populate_lr(vcpu, irq, count++);
} while (irq->source && count < kvm_vgic_global_state.nr_lr);
next:
spin_unlock(&irq->irq_lock);
if (count == kvm_vgic_global_state.nr_lr)
break;
}
vcpu->arch.vgic_cpu.used_lrs = count;
/* Nuke remaining LRs */
for ( ; count < kvm_vgic_global_state.nr_lr; count++)
vgic_clear_lr(vcpu, count);
}
/* Sync back the hardware VGIC state into our emulation after a guest's run. */
void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
{
vgic_process_maintenance_interrupt(vcpu);
vgic_fold_lr_state(vcpu);
vgic_prune_ap_list(vcpu);
}
/* Flush our emulation state into the GIC hardware before entering the guest. */
void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
{
spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock);
vgic_flush_lr_state(vcpu);
spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);
}

2
virt/kvm/arm/vgic/vgic.h
View File

@ -16,6 +16,8 @@
#ifndef __KVM_ARM_VGIC_NEW_H__
#define __KVM_ARM_VGIC_NEW_H__
#define vgic_irq_is_sgi(intid) ((intid) < VGIC_NR_SGIS)
struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
u32 intid);
bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq);