hw/intc/arm_gicv3_its: Implement support for in-kernel ITS emulation

The ITS control frame is in-kernel emulated while accesses to the
GITS_TRANSLATER are mediated through the KVM_SIGNAL_MSI ioctl (MSI
direct MSI injection advertised by the CAP_SIGNAL_MSI capability)

the kvm_gsi_direct_mapping is explicitly set to false to emphasize the
difference with GICv2M. Direct mapping cannot work with ITS since
the content of the MSI data is not the target interrupt ID but an
eventd id.

GSI routing is advertised (kvm_gsi_routing_allowed) as well as
msi/irqfd signaling (kvm_msi_via_irqfd_allowed).

The MSI frame (GITS_TRANSLATER) absolute GPA is computed on first
kvm_its_send_msi() call. It is then passed through KVM_SIGNAL_MSI
ioctl.

Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Message-id: 1474616617-366-6-git-send-email-eric.auger@redhat.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 122 insertions, 0 deletions

diff --git a/hw/intc/Makefile.objs b/hw/intc/Makefile.objs
index 23a39f7234..9cca2800d3 100644
--- a/hw/intc/Makefile.objs
+++ b/hw/intc/Makefile.objs
@@ -22,6 +22,7 @@ common-obj-$(CONFIG_OPENPIC) += openpic.o
 obj-$(CONFIG_APIC) += apic.o apic_common.o
 obj-$(CONFIG_ARM_GIC_KVM) += arm_gic_kvm.o
 obj-$(call land,$(CONFIG_ARM_GIC_KVM),$(TARGET_AARCH64)) += arm_gicv3_kvm.o
+obj-$(call land,$(CONFIG_ARM_GIC_KVM),$(TARGET_AARCH64)) += arm_gicv3_its_kvm.o
 obj-$(CONFIG_STELLARIS) += armv7m_nvic.o
 obj-$(CONFIG_EXYNOS4) += exynos4210_gic.o exynos4210_combiner.o
 obj-$(CONFIG_GRLIB) += grlib_irqmp.o
diff --git a/hw/intc/arm_gicv3_its_kvm.c b/hw/intc/arm_gicv3_its_kvm.c
new file mode 100644
index 0000000000..fc246e0cb5
--- /dev/null
+++ b/hw/intc/arm_gicv3_its_kvm.c
@@ -0,0 +1,121 @@
+/*
+ * KVM-based ITS implementation for a GICv3-based system
+ *
+ * Copyright (c) 2015 Samsung Electronics Co., Ltd.
+ * Written by Pavel Fedin <p.fedin@samsung.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "hw/intc/arm_gicv3_its_common.h"
+#include "sysemu/sysemu.h"
+#include "sysemu/kvm.h"
+#include "kvm_arm.h"
+#include "migration/migration.h"
+
+#define TYPE_KVM_ARM_ITS "arm-its-kvm"
+#define KVM_ARM_ITS(obj) OBJECT_CHECK(GICv3ITSState, (obj), TYPE_KVM_ARM_ITS)
+
+static int kvm_its_send_msi(GICv3ITSState *s, uint32_t value, uint16_t devid)
+{
+    struct kvm_msi msi;
+
+    if (unlikely(!s->translater_gpa_known)) {
+        MemoryRegion *mr = &s->iomem_its_translation;
+        MemoryRegionSection mrs;
+
+        mrs = memory_region_find(mr, 0, 1);
+        memory_region_unref(mrs.mr);
+        s->gits_translater_gpa = mrs.offset_within_address_space + 0x40;
+        s->translater_gpa_known = true;
+    }
+
+    msi.address_lo = extract64(s->gits_translater_gpa, 0, 32);
+    msi.address_hi = extract64(s->gits_translater_gpa, 32, 32);
+    msi.data = le32_to_cpu(value);
+    msi.flags = KVM_MSI_VALID_DEVID;
+    msi.devid = devid;
+    memset(msi.pad, 0, sizeof(msi.pad));
+
+    return kvm_vm_ioctl(kvm_state, KVM_SIGNAL_MSI, &msi);
+}
+
+static void kvm_arm_its_realize(DeviceState *dev, Error **errp)
+{
+    GICv3ITSState *s = ARM_GICV3_ITS_COMMON(dev);
+
+    s->dev_fd = kvm_create_device(kvm_state, KVM_DEV_TYPE_ARM_VGIC_ITS, false);
+    if (s->dev_fd < 0) {
+        error_setg_errno(errp, -s->dev_fd, "error creating in-kernel ITS");
+        return;
+    }
+
+    /* explicit init of the ITS */
+    kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_CTRL,
+                      KVM_DEV_ARM_VGIC_CTRL_INIT, NULL, true);
+
+    /* register the base address */
+    kvm_arm_register_device(&s->iomem_its_cntrl, -1, KVM_DEV_ARM_VGIC_GRP_ADDR,
+                            KVM_VGIC_ITS_ADDR_TYPE, s->dev_fd);
+
+    gicv3_its_init_mmio(s, NULL);
+
+    /*
+     * Block migration of a KVM GICv3 ITS device: the API for saving and
+     * restoring the state in the kernel is not yet available
+     */
+    error_setg(&s->migration_blocker, "vITS migration is not implemented");
+    migrate_add_blocker(s->migration_blocker);
+
+    kvm_msi_use_devid = true;
+    kvm_gsi_direct_mapping = false;
+    kvm_msi_via_irqfd_allowed = kvm_irqfds_enabled();
+}
+
+static void kvm_arm_its_init(Object *obj)
+{
+    GICv3ITSState *s = KVM_ARM_ITS(obj);
+
+    object_property_add_link(obj, "parent-gicv3",
+                             "kvm-arm-gicv3", (Object **)&s->gicv3,
+                             object_property_allow_set_link,
+                             OBJ_PROP_LINK_UNREF_ON_RELEASE,
+                             &error_abort);
+}
+
+static void kvm_arm_its_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    GICv3ITSCommonClass *icc = ARM_GICV3_ITS_COMMON_CLASS(klass);
+
+    dc->realize = kvm_arm_its_realize;
+    icc->send_msi = kvm_its_send_msi;
+}
+
+static const TypeInfo kvm_arm_its_info = {
+    .name = TYPE_KVM_ARM_ITS,
+    .parent = TYPE_ARM_GICV3_ITS_COMMON,
+    .instance_size = sizeof(GICv3ITSState),
+    .instance_init = kvm_arm_its_init,
+    .class_init = kvm_arm_its_class_init,
+};
+
+static void kvm_arm_its_register_types(void)
+{
+    type_register_static(&kvm_arm_its_info);
+}
+
+type_init(kvm_arm_its_register_types)