From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

In order to use virtio backends we need to allocate virtio-mmio
parameters (irq and base) and register corresponding buses.

Use the constants defined in public header arch-arm.h to be
aligned with the toolstack. So the number of current supported
virtio-mmio devices is 10.

For the interrupts triggering use already existing on Arm
device-model hypercall.

The toolstack should then insert the same amount of device nodes
into guest device-tree.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
---
 hw/arm/xen_arm.c            | 35 +++++++++++++++++++++++++++++++++++
 include/hw/xen/xen_native.h | 16 ++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/hw/arm/xen_arm.c b/hw/arm/xen_arm.c
index 1d3e6d481a..7393b37355 100644
--- a/hw/arm/xen_arm.c
+++ b/hw/arm/xen_arm.c
@@ -26,6 +26,7 @@
 #include "qapi/qapi-commands-migration.h"
 #include "qapi/visitor.h"
 #include "hw/boards.h"
+#include "hw/irq.h"
 #include "hw/sysbus.h"
 #include "sysemu/block-backend.h"
 #include "sysemu/tpm_backend.h"
@@ -59,6 +60,38 @@ struct XenArmState {
     } cfg;
 };
 
+/*
+ * VIRTIO_MMIO_DEV_SIZE is imported from tools/libs/light/libxl_arm.c under Xen
+ * repository.
+ *
+ * Origin: git://xenbits.xen.org/xen.git 2128143c114c
+ */
+#define VIRTIO_MMIO_DEV_SIZE   0x200
+
+#define NR_VIRTIO_MMIO_DEVICES   \
+   (GUEST_VIRTIO_MMIO_SPI_LAST - GUEST_VIRTIO_MMIO_SPI_FIRST)
+
+static void xen_set_irq(void *opaque, int irq, int level)
+{
+    xendevicemodel_set_irq_level(xen_dmod, xen_domid, irq, level);
+}
+
+static void xen_create_virtio_mmio_devices(XenArmState *xam)
+{
+    int i;
+
+    for (i = 0; i < NR_VIRTIO_MMIO_DEVICES; i++) {
+        hwaddr base = GUEST_VIRTIO_MMIO_BASE + i * VIRTIO_MMIO_DEV_SIZE;
+        qemu_irq irq = qemu_allocate_irq(xen_set_irq, NULL,
+                                         GUEST_VIRTIO_MMIO_SPI_FIRST + i);
+
+        sysbus_create_simple("virtio-mmio", base, irq);
+
+        DPRINTF("Created virtio-mmio device %d: irq %d base 0x%lx\n",
+                i, GUEST_VIRTIO_MMIO_SPI_FIRST + i, base);
+    }
+}
+
 void arch_handle_ioreq(XenIOState *state, ioreq_t *req)
 {
     hw_error("Invalid ioreq type 0x%x\n", req->type);
@@ -110,6 +143,8 @@ static void xen_arm_init(MachineState *machine)
 
     xen_register_ioreq(xam->state, machine->smp.cpus, &xen_memory_listener);
 
+    xen_create_virtio_mmio_devices(xam);
+
 #ifdef CONFIG_TPM
     if (xam->cfg.tpm_base_addr) {
         xen_enable_tpm(xam);
diff --git a/include/hw/xen/xen_native.h b/include/hw/xen/xen_native.h
index 4dce905fde..a4b1aa9e5d 100644
--- a/include/hw/xen/xen_native.h
+++ b/include/hw/xen/xen_native.h
@@ -523,4 +523,20 @@ static inline int xen_set_ioreq_server_state(domid_t dom,
                                                  enable);
 }
 
+#if CONFIG_XEN_CTRL_INTERFACE_VERSION <= 41500
+static inline int xendevicemodel_set_irq_level(xendevicemodel_handle *dmod,
+                                               domid_t domid, uint32_t irq,
+                                               unsigned int level)
+{
+    return 0;
+}
+#endif
+
+#if CONFIG_XEN_CTRL_INTERFACE_VERSION <= 41700
+#define GUEST_VIRTIO_MMIO_BASE   xen_mk_ullong(0x02000000)
+#define GUEST_VIRTIO_MMIO_SIZE   xen_mk_ullong(0x00100000)
+#define GUEST_VIRTIO_MMIO_SPI_FIRST   33
+#define GUEST_VIRTIO_MMIO_SPI_LAST    43
+#endif
+
 #endif /* QEMU_HW_XEN_NATIVE_H */
-- 
2.25.1