[RFC PATCH 10/45] KVM: arm/arm64: vgic-new: Add GICv3 world switch backend

Andre Przywara
2016-03-25T02:04:43Z

From: Marc Zyngier <marc.zyngier@arm.com>

As the GICv3 virtual interface registers differ from their GICv2
siblings, we need different handlers for processing maintenance
interrupts and reading/writing to the LRs.
Also as we store an IRQ's affinity directly as a MPIDR, we need a
separate change_affinity() implementation too.
Implement the respective handler functions and connect them to
existing code to be called if the host is using a GICv3.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
virt/kvm/arm/vgic/vgic-v3.c | 191 ++++++++++++++++++++++++++++++++++++++++++++
virt/kvm/arm/vgic/vgic.c | 8 +-
virt/kvm/arm/vgic/vgic.h | 30 +++++++
3 files changed, 225 insertions(+), 4 deletions(-)
create mode 100644 virt/kvm/arm/vgic/vgic-v3.c

diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
new file mode 100644
index 0000000..71b4bad
--- /dev/null
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -0,0 +1,191 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/irqchip/arm-gic-v3.h>
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/irqchip/arm-gic.h>
+
+#include "vgic.h"
+
+void vgic_v3_process_maintenance(struct kvm_vcpu *vcpu)
+{
+ struct vgic_v3_cpu_if *cpuif = &vcpu->arch.vgic_cpu.vgic_v3;
+ u32 model = vcpu->kvm->arch.vgic.vgic_model;
+
+ if (cpuif->vgic_misr & ICH_MISR_EOI) {
+ unsigned long eisr_bmap = cpuif->vgic_eisr;
+ int lr;
+
+ for_each_set_bit(lr, &eisr_bmap, vcpu->arch.vgic_cpu.nr_lr) {
+ u32 intid;
+ u64 val = cpuif->vgic_lr[lr];
+
+ if (model == KVM_DEV_TYPE_ARM_VGIC_V3)
+ intid = val & ICH_LR_VIRTUAL_ID_MASK;
+ else
+ intid = val & GICH_LR_VIRTUALID;
+
+ /*
+ * kvm_notify_acked_irq calls kvm_set_irq()
+ * to reset the IRQ level, which grabs the dist->lock
+ * so we call this before taking the dist->lock.
+ */
+ kvm_notify_acked_irq(vcpu->kvm, 0,
+ intid - VGIC_NR_PRIVATE_IRQS);
+
+ cpuif->vgic_lr[lr] &= ~ICH_LR_STATE; /* Useful?? */
+ cpuif->vgic_elrsr |= 1ULL << lr;
+ }
+
+ /*
+ * In the next iterations of the vcpu loop, if we sync
+ * the vgic state after flushing it, but before
+ * entering the guest (this happens for pending
+ * signals and vmid rollovers), then make sure we
+ * don't pick up any old maintenance interrupts here.
+ */
+ cpuif->vgic_eisr = 0;
+ }
+
+ cpuif->vgic_hcr &= ~ICH_HCR_UIE;
+}
+
+void vgic_v3_set_underflow(struct kvm_vcpu *vcpu)
+{
+ struct vgic_v3_cpu_if *cpuif = &vcpu->arch.vgic_cpu.vgic_v3;
+
+ cpuif->vgic_hcr |= ICH_HCR_UIE;
+}
+
+void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)
+{
+ struct vgic_v3_cpu_if *cpuif = &vcpu->arch.vgic_cpu.vgic_v3;
+ u32 model = vcpu->kvm->arch.vgic.vgic_model;
+ int lr;
+
+ /* Assumes ap_list_lock held */
+
+ for (lr = 0; lr < vcpu->arch.vgic_cpu.used_lrs; lr++) {
+ u64 val = cpuif->vgic_lr[lr];
+ u32 intid;
+ struct vgic_irq *irq;
+
+ if (model == KVM_DEV_TYPE_ARM_VGIC_V3)
+ intid = val & ICH_LR_VIRTUAL_ID_MASK;
+ else
+ intid = val & GICH_LR_VIRTUALID;
+ irq = vgic_get_irq(vcpu->kvm, vcpu, intid);
+
+ spin_lock(&irq->irq_lock);
+
+ /* Always preserve the active bit */
+ irq->active = !!(val & ICH_LR_ACTIVE_BIT);
+
+ /* Edge is the only case where we preserve the pending bit */
+ if (irq->config == VGIC_CONFIG_EDGE &&
+ (val & ICH_LR_PENDING_BIT)) {
+ irq->pending = true;
+
+ if (intid < VGIC_NR_SGIS &&
+ model == KVM_DEV_TYPE_ARM_VGIC_V2) {
+ u32 cpuid = val & GICH_LR_PHYSID_CPUID;
+
+ cpuid >>= GICH_LR_PHYSID_CPUID_SHIFT;
+ irq->source |= (1 << cpuid);
+ }
+ }
+
+ /* Clear soft pending state when level irqs have been acked */
+ if (irq->config == VGIC_CONFIG_LEVEL &&
+ !(val & ICH_LR_PENDING_BIT)) {
+ irq->soft_pending = false;
+ irq->pending = irq->line_level;
+ }
+
+ spin_unlock(&irq->irq_lock);
+ }
+}
+
+/* Requires the irq to be locked already */
+void vgic_v3_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr)
+{
+ u32 model = vcpu->kvm->arch.vgic.vgic_model;
+ u64 val;
+
+ if (!irq) {
+ val = 0;
+ goto out;
+ }
+
+ val = irq->intid;
+
+ if (irq->pending) {
+ val |= ICH_LR_PENDING_BIT;
+
+ if (irq->config == VGIC_CONFIG_EDGE)
+ irq->pending = false;
+
+ if (irq->intid < VGIC_NR_SGIS &&
+ model == KVM_DEV_TYPE_ARM_VGIC_V2) {
+ u32 src = ffs(irq->source);
+
+ BUG_ON(!src);
+ val |= (src - 1) << GICH_LR_PHYSID_CPUID_SHIFT;
+ irq->source &= ~(1 << (src - 1));
+ if (irq->source)
+ irq->pending = true;
+ }
+ }
+
+ if (irq->active)
+ val |= ICH_LR_ACTIVE_BIT;
+
+ if (irq->hw) {
+ val |= ICH_LR_HW;
+ val |= ((u64)irq->hwintid) << ICH_LR_PHYS_ID_SHIFT;
+ } else {
+ if (irq->config == VGIC_CONFIG_LEVEL)
+ val |= ICH_LR_EOI;
+ }
+
+ /*
+ * Currently all guest IRQs are Group1, as Group0 would result
+ * in a FIQ in the guest, which it wouldn't expect.
+ * Eventually we want to make this configurable, so we may
+ * revisit this in the future.
+ */
+ if (model == KVM_DEV_TYPE_ARM_VGIC_V3)
+ val |= ICH_LR_GROUP;
+
+out:
+ vcpu->arch.vgic_cpu.vgic_v3.vgic_lr[lr] = val;
+}
+
+void vgic_v3_irq_change_affinity(struct kvm *kvm, u32 intid, u64 mpidr)
+{
+ struct vgic_dist *dist = &kvm->arch.vgic;
+ struct vgic_irq *irq;
+ struct kvm_vcpu *vcpu;
+
+ BUG_ON(intid <= VGIC_MAX_PRIVATE || intid > 1019);
+ BUG_ON(dist->vgic_model != KVM_DEV_TYPE_ARM_VGIC_V3);
+
+ irq = vgic_get_irq(kvm, NULL, intid);
+ vcpu = kvm_mpidr_to_vcpu(kvm, mpidr);
+
+ spin_lock(&irq->irq_lock);
+ irq->target_vcpu = vcpu;
+ spin_unlock(&irq->irq_lock);
+}
diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index 90a85bf..9eb031e8 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -368,7 +368,7 @@ static inline void vgic_process_maintenance_interrupt(struct kvm_vcpu *vcpu)
if (kvm_vgic_global_state.type == VGIC_V2)
vgic_v2_process_maintenance(vcpu);
else
- WARN(1, "GICv3 Not Implemented\n");
+ vgic_v3_process_maintenance(vcpu);
}

static inline void vgic_fold_lr_state(struct kvm_vcpu *vcpu)
@@ -376,7 +376,7 @@ static inline void vgic_fold_lr_state(struct kvm_vcpu *vcpu)
if (kvm_vgic_global_state.type == VGIC_V2)
vgic_v2_fold_lr_state(vcpu);
else
- WARN(1, "GICv3 Not Implemented\n");
+ vgic_v3_fold_lr_state(vcpu);
}

/*
@@ -390,7 +390,7 @@ static inline void vgic_populate_lr(struct kvm_vcpu *vcpu,
if (kvm_vgic_global_state.type == VGIC_V2)
vgic_v2_populate_lr(vcpu, irq, lr);
else
- WARN(1, "GICv3 Not Implemented\n");
+ vgic_v3_populate_lr(vcpu, irq, lr);
}

static inline void vgic_set_underflow(struct kvm_vcpu *vcpu)
@@ -398,7 +398,7 @@ static inline void vgic_set_underflow(struct kvm_vcpu *vcpu)
if (kvm_vgic_global_state.type == VGIC_V2)
vgic_v2_set_underflow(vcpu);
else
- WARN(1, "GICv3 Not Implemented\n");
+ vgic_v3_set_underflow(vcpu);
}

static int compute_ap_list_depth(struct kvm_vcpu *vcpu)
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index 95ef3cf..53730ba 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -26,4 +26,34 @@ 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_set_underflow(struct kvm_vcpu *vcpu);

+#ifdef CONFIG_KVM_ARM_VGIC_V3
+void vgic_v3_irq_change_affinity(struct kvm *kvm, u32 intid, u64 mpidr);
+void vgic_v3_process_maintenance(struct kvm_vcpu *vcpu);
+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_set_underflow(struct kvm_vcpu *vcpu);
+#else
+static inline void vgic_v3_irq_change_affinity(struct kvm *kvm, u32 intid,
+ u64 mpidr)
+{
+}
+
+static inline void vgic_v3_process_maintenance(struct kvm_vcpu *vcpu)
+{
+}
+
+static inline void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)
+{
+}
+
+static inline void vgic_v3_populate_lr(struct kvm_vcpu *vcpu,
+ struct vgic_irq *irq, int lr)
+{
+}
+
+static inline void vgic_v3_set_underflow(struct kvm_vcpu *vcpu)
+{
+}
+#endif
+
#endif
--
2.7.3