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authorMarc Zyngier <marc.zyngier@arm.com>2018-03-06 21:48:01 +0000
committerMarc Zyngier <marc.zyngier@arm.com>2018-03-14 18:31:04 +0000
commit16ca6a607d84bef0129698d8d808f501afd08d43 (patch)
treedd8c4a36c3c185e82003cd125a092cb42845de21 /virt
parent76600428c3677659e3c3633bb4f2ea302220a275 (diff)
downloadlinux-16ca6a607d84bef0129698d8d808f501afd08d43.tar.bz2
KVM: arm/arm64: vgic: Don't populate multiple LRs with the same vintid
The vgic code is trying to be clever when injecting GICv2 SGIs, and will happily populate LRs with the same interrupt number if they come from multiple vcpus (after all, they are distinct interrupt sources). Unfortunately, this is against the letter of the architecture, and the GICv2 architecture spec says "Each valid interrupt stored in the List registers must have a unique VirtualID for that virtual CPU interface.". GICv3 has similar (although slightly ambiguous) restrictions. This results in guests locking up when using GICv2-on-GICv3, for example. The obvious fix is to stop trying so hard, and inject a single vcpu per SGI per guest entry. After all, pending SGIs with multiple source vcpus are pretty rare, and are mostly seen in scenario where the physical CPUs are severely overcomitted. But as we now only inject a single instance of a multi-source SGI per vcpu entry, we may delay those interrupts for longer than strictly necessary, and run the risk of injecting lower priority interrupts in the meantime. In order to address this, we adopt a three stage strategy: - If we encounter a multi-source SGI in the AP list while computing its depth, we force the list to be sorted - When populating the LRs, we prevent the injection of any interrupt of lower priority than that of the first multi-source SGI we've injected. - Finally, the injection of a multi-source SGI triggers the request of a maintenance interrupt when there will be no pending interrupt in the LRs (HCR_NPIE). At the point where the last pending interrupt in the LRs switches from Pending to Active, the maintenance interrupt will be delivered, allowing us to add the remaining SGIs using the same process. Cc: stable@vger.kernel.org Fixes: 0919e84c0fc1 ("KVM: arm/arm64: vgic-new: Add IRQ sync/flush framework") Acked-by: Christoffer Dall <cdall@kernel.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/arm/vgic/vgic-v2.c9
-rw-r--r--virt/kvm/arm/vgic/vgic-v3.c9
-rw-r--r--virt/kvm/arm/vgic/vgic.c61
-rw-r--r--virt/kvm/arm/vgic/vgic.h2
4 files changed, 65 insertions, 16 deletions
diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
index e9d840a75e7b..29556f71b691 100644
--- a/virt/kvm/arm/vgic/vgic-v2.c
+++ b/virt/kvm/arm/vgic/vgic-v2.c
@@ -37,6 +37,13 @@ void vgic_v2_init_lrs(void)
vgic_v2_write_lr(i, 0);
}
+void vgic_v2_set_npie(struct kvm_vcpu *vcpu)
+{
+ struct vgic_v2_cpu_if *cpuif = &vcpu->arch.vgic_cpu.vgic_v2;
+
+ cpuif->vgic_hcr |= GICH_HCR_NPIE;
+}
+
void vgic_v2_set_underflow(struct kvm_vcpu *vcpu)
{
struct vgic_v2_cpu_if *cpuif = &vcpu->arch.vgic_cpu.vgic_v2;
@@ -64,7 +71,7 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu)
int lr;
unsigned long flags;
- cpuif->vgic_hcr &= ~GICH_HCR_UIE;
+ cpuif->vgic_hcr &= ~(GICH_HCR_UIE | GICH_HCR_NPIE);
for (lr = 0; lr < vgic_cpu->used_lrs; lr++) {
u32 val = cpuif->vgic_lr[lr];
diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index 6b329414e57a..0ff2006f3781 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -26,6 +26,13 @@ static bool group1_trap;
static bool common_trap;
static bool gicv4_enable;
+void vgic_v3_set_npie(struct kvm_vcpu *vcpu)
+{
+ struct vgic_v3_cpu_if *cpuif = &vcpu->arch.vgic_cpu.vgic_v3;
+
+ cpuif->vgic_hcr |= ICH_HCR_NPIE;
+}
+
void vgic_v3_set_underflow(struct kvm_vcpu *vcpu)
{
struct vgic_v3_cpu_if *cpuif = &vcpu->arch.vgic_cpu.vgic_v3;
@@ -47,7 +54,7 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)
int lr;
unsigned long flags;
- cpuif->vgic_hcr &= ~ICH_HCR_UIE;
+ cpuif->vgic_hcr &= ~(ICH_HCR_UIE | ICH_HCR_NPIE);
for (lr = 0; lr < vgic_cpu->used_lrs; lr++) {
u64 val = cpuif->vgic_lr[lr];
diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index 0001858a2c23..8201899126f6 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -710,22 +710,37 @@ static inline void vgic_set_underflow(struct kvm_vcpu *vcpu)
vgic_v3_set_underflow(vcpu);
}
+static inline void vgic_set_npie(struct kvm_vcpu *vcpu)
+{
+ if (kvm_vgic_global_state.type == VGIC_V2)
+ vgic_v2_set_npie(vcpu);
+ else
+ vgic_v3_set_npie(vcpu);
+}
+
/* Requires the ap_list_lock to be held. */
-static int compute_ap_list_depth(struct kvm_vcpu *vcpu)
+static int compute_ap_list_depth(struct kvm_vcpu *vcpu,
+ bool *multi_sgi)
{
struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
struct vgic_irq *irq;
int count = 0;
+ *multi_sgi = false;
+
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
+ if (vgic_irq_is_sgi(irq->intid) && irq->source) {
+ int w = hweight8(irq->source);
+
+ count += w;
+ *multi_sgi |= (w > 1);
+ } else {
count++;
+ }
spin_unlock(&irq->irq_lock);
}
return count;
@@ -736,28 +751,43 @@ 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;
+ int count;
+ bool npie = false;
+ bool multi_sgi;
+ u8 prio = 0xff;
DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));
- if (compute_ap_list_depth(vcpu) > kvm_vgic_global_state.nr_lr)
+ count = compute_ap_list_depth(vcpu, &multi_sgi);
+ if (count > kvm_vgic_global_state.nr_lr || multi_sgi)
vgic_sort_ap_list(vcpu);
+ count = 0;
+
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.
+ * If we have multi-SGIs in the pipeline, we need to
+ * guarantee that they are all seen before any IRQ of
+ * lower priority. In that case, we need to filter out
+ * these interrupts by exiting early. This is easy as
+ * the AP list has been sorted already.
*/
- do {
+ if (multi_sgi && irq->priority > prio) {
+ spin_unlock(&irq->irq_lock);
+ break;
+ }
+
+ if (likely(vgic_target_oracle(irq) == vcpu)) {
vgic_populate_lr(vcpu, irq, count++);
- } while (irq->source && count < kvm_vgic_global_state.nr_lr);
-next:
+ if (irq->source) {
+ npie = true;
+ prio = irq->priority;
+ }
+ }
+
spin_unlock(&irq->irq_lock);
if (count == kvm_vgic_global_state.nr_lr) {
@@ -768,6 +798,9 @@ next:
}
}
+ if (npie)
+ vgic_set_npie(vcpu);
+
vcpu->arch.vgic_cpu.used_lrs = count;
/* Nuke remaining LRs */
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index 5b11859a1a1e..f5b8519e5546 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -160,6 +160,7 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu);
void vgic_v2_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr);
void vgic_v2_clear_lr(struct kvm_vcpu *vcpu, int lr);
void vgic_v2_set_underflow(struct kvm_vcpu *vcpu);
+void vgic_v2_set_npie(struct kvm_vcpu *vcpu);
int vgic_v2_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr);
int vgic_v2_dist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
int offset, u32 *val);
@@ -189,6 +190,7 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu);
void vgic_v3_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr);
void vgic_v3_clear_lr(struct kvm_vcpu *vcpu, int lr);
void vgic_v3_set_underflow(struct kvm_vcpu *vcpu);
+void vgic_v3_set_npie(struct kvm_vcpu *vcpu);
void vgic_v3_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
void vgic_v3_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
void vgic_v3_enable(struct kvm_vcpu *vcpu);