[XEN PATCH v2 3/5] xen/arm: configure dom0less domain for enabling xenstore after boot

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

From: Luca Miccio <lucmiccio@xxxxxxxxx>

If "xen,enhanced" is enabled, then add to dom0less domains:

- the hypervisor node in device tree
- the xenstore event channel

The xenstore event channel is also used for the first notification to
let the guest know that xenstore has become available.

Signed-off-by: Luca Miccio <lucmiccio@xxxxxxxxx>
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
CC: Julien Grall <julien@xxxxxxx>
CC: Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
CC: Bertrand Marquis <bertrand.marquis@xxxxxxx>

---
Changes in v2:
- set HVM_PARAM_STORE_PFN to ~0ULL at domain creation
- in alloc_xenstore_evtchn do not call _evtchn_alloc_unbound
---
 xen/arch/arm/domain_build.c | 43 +++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 9144d6c0b6..251d933c8e 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -27,6 +27,7 @@
 #include <asm/setup.h>
 #include <asm/cpufeature.h>
 #include <asm/domain_build.h>
+#include <xen/event.h>
 
 #include <xen/irq.h>
 #include <xen/grant_table.h>
@@ -2619,6 +2620,8 @@ static int __init prepare_dtb_domU(struct domain *d, 
struct kernel_info *kinfo)
     int ret;
 
     kinfo->phandle_gic = GUEST_PHANDLE_GIC;
+    kinfo->gnttab_start = GUEST_GNTTAB_BASE;
+    kinfo->gnttab_size = GUEST_GNTTAB_SIZE;
 
     addrcells = GUEST_ROOT_ADDRESS_CELLS;
     sizecells = GUEST_ROOT_SIZE_CELLS;
@@ -2693,6 +2696,13 @@ static int __init prepare_dtb_domU(struct domain *d, 
struct kernel_info *kinfo)
             goto err;
     }
 
+    if ( kinfo->dom0less_enhanced )
+    {
+        ret = make_hypervisor_node(d, kinfo, addrcells, sizecells);
+        if ( ret )
+            goto err;
+    }
+
     ret = fdt_end_node(kinfo->fdt);
     if ( ret < 0 )
         goto err;
@@ -2959,6 +2969,27 @@ static int __init construct_domain(struct domain *d, 
struct kernel_info *kinfo)
     return 0;
 }
 
+static int __init alloc_xenstore_evtchn(struct domain *d)
+{
+    struct evtchn *chn;
+    int port;
+
+    if ( (port = get_free_port(d)) < 0 )
+    {
+        printk("Failed allocating event channel for domain\n");
+        return port;
+    }
+    chn = evtchn_from_port(d, port);
+
+    chn->state = ECS_UNBOUND;
+    chn->u.unbound.remote_domid = hardware_domain->domain_id;
+    evtchn_port_init(d, chn);
+
+    d->arch.hvm.params[HVM_PARAM_STORE_EVTCHN] = chn->port;
+
+    return 0;
+}
+
 static int __init construct_domU(struct domain *d,
                                  const struct dt_device_node *node)
 {
@@ -3014,7 +3045,19 @@ static int __init construct_domU(struct domain *d,
         return rc;
 
     if ( kinfo.vpl011 )
+    {
         rc = domain_vpl011_init(d, NULL);
+        if ( rc < 0 )
+            return rc;
+    }
+
+    if ( kinfo.dom0less_enhanced )
+    {
+        rc = alloc_xenstore_evtchn(d);
+        if ( rc < 0 )
+            return rc;
+        d->arch.hvm.params[HVM_PARAM_STORE_PFN] = ~0ULL;
+    }
 
     return rc;
 }
-- 
2.25.1