From: Marc Zyngier <marc.zyngier@xxxxxxx>
So far, the only user of the mapped interrupt facility was the timer:
the physical distributor active state needed to be context-switched
for each vcpu, as the device is shared across all vcpus.
This patch allows to indicate whether a mapped IRQ originates from a
device shared between several VMs (typically the architected timer) or
from a device assigned to a single VM.
A new "shared" flag is added to irq_phys_map and passed to the
mapping function.
the VGIC state machine is adapted to support the non shared mapped IRQs:
- only can be sampled when it is pending
- when queueing the IRQ (programming the LR), the pending state is
removed as for edge sensitive IRQs
- queued state is not modelled. Level state is not modelled
- its injection with high level always is valid since steming from the HW.
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
v3 -> v4:
- reword the patch title
- rebase on [PATCH v2 0/8] Rework architected timer and forwarded IRQs
handling
- renamed shared_hw into non_shared_mapped_irq;
- handle edge-sensitive unshared mapped IRQs
- vgic_validate_injection rejects mapped unshared edge with
level == 0
---
include/kvm/arm_vgic.h | 3 ++-
virt/kvm/arm/arch_timer.c | 2 +-
virt/kvm/arm/vgic.c | 37 ++++++++++++++++++++++++++++---------
3 files changed, 31 insertions(+), 11 deletions(-)
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 9c747cb..9bf6a30 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -158,6 +158,7 @@ struct irq_phys_map {
u32 virt_irq;
u32 phys_irq;
u32 irq;
+ bool shared;
};
struct irq_phys_map_entry {
@@ -344,7 +345,7 @@ void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg);
int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu);
int kvm_vgic_vcpu_active_irq(struct kvm_vcpu *vcpu);
struct irq_phys_map *kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu,
- int virt_irq, int irq);
+ int virt_irq, int irq, bool shared);
int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, struct irq_phys_map *map);
#define irqchip_in_kernel(k) (!!((k)->arch.vgic.in_kernel))
diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index 21a0ab2..9eea751 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -289,7 +289,7 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu,
* Tell the VGIC that the virtual interrupt is tied to a
* physical interrupt. We do that once per VCPU.
*/
- map = kvm_vgic_map_phys_irq(vcpu, irq->irq, host_vtimer_irq);
+ map = kvm_vgic_map_phys_irq(vcpu, irq->irq, host_vtimer_irq, true);
if (WARN_ON(IS_ERR(map)))
return PTR_ERR(map);
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index bc30d93..dba8eb6 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -410,7 +410,11 @@ void vgic_cpu_irq_clear(struct kvm_vcpu *vcpu, int irq)
static bool vgic_can_sample_irq(struct kvm_vcpu *vcpu, int irq)
{
- return !vgic_irq_is_queued(vcpu, irq);
+ struct irq_phys_map *map = vgic_irq_map_search(vcpu, irq);
+ bool non_shared_mapped_irq = map && !map->shared;
+
+ return !vgic_irq_is_queued(vcpu, irq) ||
+ (non_shared_mapped_irq && vgic_dist_irq_is_pending(vcpu, irq));
}
/**
@@ -1205,11 +1209,14 @@ bool vgic_queue_irq(struct kvm_vcpu *vcpu, u8 sgi_source_id, int irq)
static bool vgic_queue_hwirq(struct kvm_vcpu *vcpu, int irq)
{
+ struct irq_phys_map *map = vgic_irq_map_search(vcpu, irq);
+ bool non_shared_mapped_irq = map && !map->shared;
+
if (!vgic_can_sample_irq(vcpu, irq))
return true; /* level interrupt, already queued */
if (vgic_queue_irq(vcpu, 0, irq)) {
- if (vgic_irq_is_edge(vcpu, irq)) {
+ if (vgic_irq_is_edge(vcpu, irq) || non_shared_mapped_irq) {
vgic_dist_irq_clear_pending(vcpu, irq);
vgic_cpu_irq_clear(vcpu, irq);
} else {
@@ -1292,6 +1299,8 @@ static int process_queued_irq(struct kvm_vcpu *vcpu,
int lr, struct vgic_lr vlr)
{
int pending = 0;
+ struct irq_phys_map *map = vgic_irq_map_search(vcpu, vlr.irq);
+ bool non_shared_mapped_irq = map && !map->shared;
/*
* If the IRQ was EOIed (called from vgic_process_maintenance) or it
@@ -1312,8 +1321,7 @@ static int process_queued_irq(struct kvm_vcpu *vcpu,
vgic_irq_clear_queued(vcpu, vlr.irq);
/* Any additional pending interrupt? */
- if (vgic_irq_is_edge(vcpu, vlr.irq)) {
- BUG_ON(!(vlr.state & LR_HW));
+ if (vgic_irq_is_edge(vcpu, vlr.irq) || non_shared_mapped_irq) {
pending = vgic_dist_irq_is_pending(vcpu, vlr.irq);
} else {
if (vgic_dist_irq_get_level(vcpu, vlr.irq)) {
@@ -1506,18 +1514,23 @@ void vgic_kick_vcpus(struct kvm *kvm)
}
}
-static int vgic_validate_injection(struct kvm_vcpu *vcpu, int irq, int level)
+static int vgic_validate_injection(struct kvm_vcpu *vcpu,
+ struct irq_phys_map *map,
+ int irq, int level)
{
int edge_triggered = vgic_irq_is_edge(vcpu, irq);
/*
* Only inject an interrupt if:
* - edge triggered and we have a rising edge
- * - level triggered and we change level
+ * - level triggered and we change level (except for
+ * mapped unshared IRQs where level is not modelled)
*/
if (edge_triggered) {
int state = vgic_dist_irq_is_pending(vcpu, irq);
return level > state;
+ } else if (map && !map->shared) {
+ return true;
} else {
int state = vgic_dist_irq_get_level(vcpu, irq);
return level != state;
@@ -1545,7 +1558,7 @@ static int vgic_update_irq_pending(struct kvm *kvm, int cpuid,
edge_triggered = vgic_irq_is_edge(vcpu, irq_num);
level_triggered = !edge_triggered;
- if (!vgic_validate_injection(vcpu, irq_num, level)) {
+ if (!vgic_validate_injection(vcpu, map, irq_num, level)) {
ret = false;
goto out;
}
@@ -1718,16 +1731,20 @@ static struct list_head *vgic_get_irq_phys_map_list(struct kvm_vcpu *vcpu,
* @vcpu: The VCPU pointer
* @virt_irq: The virtual irq number
* @irq: The Linux IRQ number
+ * @shared: Indicates if the interrupt has to be context-switched or
+ * if it is private to a VM
*
* Establish a mapping between a guest visible irq (@virt_irq) and a
* Linux irq (@irq). On injection, @virt_irq will be associated with
* the physical interrupt represented by @irq. This mapping can be
* established multiple times as long as the parameters are the same.
+ * If @shared is true, the active state of the interrupt will be
+ * context-switched.
*
* Returns a valid pointer on success, and an error pointer otherwise
*/
struct irq_phys_map *kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu,
- int virt_irq, int irq)
+ int virt_irq, int irq, bool shared)
{
struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
struct list_head *root = vgic_get_irq_phys_map_list(vcpu, virt_irq);
@@ -1761,7 +1778,8 @@ struct irq_phys_map *kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu,
if (map) {
/* Make sure this mapping matches */
if (map->phys_irq != phys_irq ||
- map->irq != irq)
+ map->irq != irq ||
+ map->shared != shared)
map = ERR_PTR(-EINVAL);
/* Found an existing, valid mapping */
@@ -1772,6 +1790,7 @@ struct irq_phys_map *kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu,
map->virt_irq = virt_irq;
map->phys_irq = phys_irq;
map->irq = irq;
+ map->shared = shared;
list_add_tail_rcu(&entry->entry, root);
--
1.9.1
--
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