[RFC PATCH V1 06/12] libxl: Introduce basic virtio-mmio support on Arm

[Oleksandr Tyshchenko <olekstysh@gmail.com>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

This patch creates specific device node in the Guest device-tree
with allocated MMIO range and SPI interrupt if specific 'virtio'
property is present in domain config.

Please note, this patch breaks device passthrough use-case which
will be fixed in one of the follow-up patches.

Please note, this is a split/cleanup of Julien's PoC:
"Add support for Guest IO forwarding to a device emulator"

Signed-off-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
---
 tools/libxl/libxl_arm.c     | 39 +++++++++++++++++++++++++++++++++++++++
 tools/libxl/libxl_types.idl |  1 +
 tools/xl/xl_parse.c         |  1 +
 3 files changed, 41 insertions(+)

diff --git a/tools/libxl/libxl_arm.c b/tools/libxl/libxl_arm.c
index 34f8a29..620b499 100644
--- a/tools/libxl/libxl_arm.c
+++ b/tools/libxl/libxl_arm.c
@@ -68,6 +68,10 @@ int libxl__arch_domain_prepare_config(libxl__gc *gc,
             nr_spis = spi + 1;
     }
 
+
+    /* XXX: Handle properly virtio */
+    nr_spis = 1;
+
     LOG(DEBUG, "Configure the domain");
 
     config->arch.nr_spis = nr_spis;
@@ -659,6 +663,37 @@ static int make_vpl011_uart_node(libxl__gc *gc, void *fdt,
     return 0;
 }
 
+#define GUEST_VIRTIO_MMIO_BASE  xen_mk_ullong(0x02000000)
+#define GUEST_VIRTIO_MMIO_SIZE  xen_mk_ullong(0x200)
+#define GUEST_VIRTIO_MMIO_SPI   33
+
+static int make_virtio_mmio_node(libxl__gc *gc, void *fdt)
+{
+    int res;
+    gic_interrupt intr;
+
+    /* XXX: Add address in the node name */
+    res = fdt_begin_node(fdt, "virtio");
+    if (res) return res;
+
+    res = fdt_property_compat(gc, fdt, 1, "virtio,mmio");
+    if (res) return res;
+
+    res = fdt_property_regs(gc, fdt, GUEST_ROOT_ADDRESS_CELLS, GUEST_ROOT_SIZE_CELLS,
+                            1, GUEST_VIRTIO_MMIO_BASE, GUEST_VIRTIO_MMIO_SIZE);
+    if (res) return res;
+
+    set_interrupt(intr, GUEST_VIRTIO_MMIO_SPI, 0xf, DT_IRQ_TYPE_EDGE_RISING);
+    res = fdt_property_interrupts(gc, fdt, &intr, 1);
+    if (res) return res;
+
+    res = fdt_end_node(fdt);
+    if (res) return res;
+
+    return 0;
+
+}
+
 static const struct arch_info *get_arch_info(libxl__gc *gc,
                                              const struct xc_dom_image *dom)
 {
@@ -962,6 +997,9 @@ next_resize:
         if (info->tee == LIBXL_TEE_TYPE_OPTEE)
             FDT( make_optee_node(gc, fdt) );
 
+        if (libxl_defbool_val(info->arch_arm.virtio))
+            FDT( make_virtio_mmio_node(gc, fdt) );
+
         if (pfdt)
             FDT( copy_partial_fdt(gc, fdt, pfdt) );
 
@@ -1179,6 +1217,7 @@ void libxl__arch_domain_build_info_setdefault(libxl__gc *gc,
 {
     /* ACPI is disabled by default */
     libxl_defbool_setdefault(&b_info->acpi, false);
+    libxl_defbool_setdefault(&b_info->arch_arm.virtio, false);
 
     if (b_info->type != LIBXL_DOMAIN_TYPE_PV)
         return;
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 9d3f05f..b054bf9 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -639,6 +639,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
 
 
     ("arch_arm", Struct(None, [("gic_version", libxl_gic_version),
+                               ("virtio", libxl_defbool),
                                ("vuart", libxl_vuart_type),
                               ])),
     # Alternate p2m is not bound to any architecture or guest type, as it is
diff --git a/tools/xl/xl_parse.c b/tools/xl/xl_parse.c
index 61b4ef7..b8306aa 100644
--- a/tools/xl/xl_parse.c
+++ b/tools/xl/xl_parse.c
@@ -2579,6 +2579,7 @@ skip_usbdev:
     }
 
     xlu_cfg_get_defbool(config, "dm_restrict", &b_info->dm_restrict, 0);
+    xlu_cfg_get_defbool(config, "virtio", &b_info->arch_arm.virtio, 0);
 
     if (c_info->type == LIBXL_DOMAIN_TYPE_HVM) {
         if (!xlu_cfg_get_string (config, "vga", &buf, 0)) {
-- 
2.7.4