[PATCH 2/3] KVM: arm: Introduce software emulation of vGICv2 CPU interface

[Pavel Fedin]

The emulation code is activated by setting params->vcpu_base to zero

Signed-off-by: Pavel Fedin <p.fe...@samsung.com>
---
 include/kvm/arm_vgic.h      |  1 +
 virt/kvm/arm/vgic-v2-emul.c | 60 ++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 55 insertions(+), 6 deletions(-)

diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 31cda96..fa533e7 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -254,6 +254,7 @@ struct vgic_dist {
 
        struct vgic_vm_ops      vm_ops;
        struct vgic_io_device   dist_iodev;
+       struct vgic_io_device   cpu_iodev;
        struct vgic_io_device   *redist_iodevs;
 };
 
diff --git a/virt/kvm/arm/vgic-v2-emul.c b/virt/kvm/arm/vgic-v2-emul.c
index 1390797..c2e1274 100644
--- a/virt/kvm/arm/vgic-v2-emul.c
+++ b/virt/kvm/arm/vgic-v2-emul.c
@@ -404,6 +404,8 @@ static const struct vgic_io_range vgic_dist_ranges[] = {
        {}
 };
 
+static const struct vgic_io_range vgic_cpu_ranges[];
+
 static void vgic_dispatch_sgi(struct kvm_vcpu *vcpu, u32 reg)
 {
        struct kvm *kvm = vcpu->kvm;
@@ -520,12 +522,20 @@ static int vgic_v2_map_resources(struct kvm *kvm,
                goto out_unregister;
        }
 
-       ret = kvm_phys_addr_ioremap(kvm, dist->vgic_cpu_base,
-                                   params->vcpu_base, KVM_VGIC_V2_CPU_SIZE,
-                                   true);
-       if (ret) {
-               kvm_err("Unable to remap VGIC CPU to VCPU\n");
-               goto out_unregister;
+       if (params->vcpu_base) {
+               ret = kvm_phys_addr_ioremap(kvm, dist->vgic_cpu_base,
+                                           params->vcpu_base,
+                                           KVM_VGIC_V2_CPU_SIZE, true);
+               if (ret) {
+                       kvm_err("Unable to remap VGIC CPU to VCPU\n");
+                       goto out_unregister;
+               }
+       } else {
+               vgic_register_kvm_io_dev(kvm, dist->vgic_cpu_base,
+                                        KVM_VGIC_V2_CPU_SIZE,
+                                        vgic_cpu_ranges, -1,
+                                        &dist->cpu_iodev);
+               dist->sw_cpuif = true;
        }
 
        dist->ready = true;
@@ -611,6 +621,34 @@ static bool handle_cpu_mmio_misc(struct kvm_vcpu *vcpu,
        return updated;
 }
 
+static bool handle_mmio_intack(struct kvm_vcpu *vcpu,
+                              struct kvm_exit_mmio *mmio, phys_addr_t offset)
+{
+       int pending;
+
+       if (mmio->is_write)
+               return false;
+
+       pending = vgic_get_pending_irq(vcpu);
+       mmio_data_write(mmio, ~0, pending);
+
+       return true;
+}
+
+static bool handle_mmio_eoi(struct kvm_vcpu *vcpu,
+                           struct kvm_exit_mmio *mmio, phys_addr_t offset)
+{
+       u32 reg;
+
+       if (!mmio->is_write)
+               return false;
+
+       reg = mmio_data_read(mmio, ~0);
+       vgic_clear_pending_irq(vcpu, reg);
+
+       return false;
+}
+
 static bool handle_mmio_abpr(struct kvm_vcpu *vcpu,
                             struct kvm_exit_mmio *mmio, phys_addr_t offset)
 {
@@ -645,6 +683,16 @@ static const struct vgic_io_range vgic_cpu_ranges[] = {
                .handle_mmio    = handle_cpu_mmio_misc,
        },
        {
+               .base           = GIC_CPU_INTACK,
+               .len            = 4,
+               .handle_mmio    = handle_mmio_intack,
+       },
+       {
+               .base           = GIC_CPU_EOI,
+               .len            = 4,
+               .handle_mmio    = handle_mmio_eoi,
+       },
+       {
                .base           = GIC_CPU_ALIAS_BINPOINT,
                .len            = 4,
                .handle_mmio    = handle_mmio_abpr,
-- 
2.1.4

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