[PATCH v5 08/12] x86/hyperlaunch: add domain id parsing to domain config

[Alejandro Vallejo <agarciav@xxxxxxx>]

From: "Daniel P. Smith" <dpsmith@xxxxxxxxxxxxxxxxxxxx>

Introduce the ability to specify the desired domain id for the domain
definition. The domain id will be populated in the domid property of the
domain node in the device tree configuration.

Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Alejandro Vallejo <agarciav@xxxxxxx>
---
v5:
  * Added missing domid to printk (also rewrote it).
---
 xen/arch/x86/setup.c            |  5 ++--
 xen/common/domain-builder/fdt.c | 52 ++++++++++++++++++++++++++++++++-
 2 files changed, 54 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 661b80138a..ece77079d8 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1042,8 +1042,9 @@ static struct domain *__init create_dom0(struct boot_info 
*bi)
     if ( iommu_enabled )
         dom0_cfg.flags |= XEN_DOMCTL_CDF_iommu;
 
-    /* Create initial domain.  Not d0 for pvshim. */
-    bd->domid = get_initial_domain_id();
+    if ( bd->domid == DOMID_INVALID )
+        /* Create initial domain.  Not d0 for pvshim. */
+        bd->domid = get_initial_domain_id();
     d = domain_create(bd->domid, &dom0_cfg,
                       pv_shim ? 0 : CDF_privileged | CDF_hardware);
     if ( IS_ERR(d) )
diff --git a/xen/common/domain-builder/fdt.c b/xen/common/domain-builder/fdt.c
index 144fcc75b5..5a5b3c8806 100644
--- a/xen/common/domain-builder/fdt.c
+++ b/xen/common/domain-builder/fdt.c
@@ -2,6 +2,7 @@
 /*
  * Copyright (C) 2024, Apertus Solutions, LLC
  */
+#include <xen/domain.h>
 #include <xen/err.h>
 #include <xen/init.h>
 #include <xen/lib.h>
@@ -188,12 +189,54 @@ static int __init fdt_read_multiboot_module(const void 
*fdt, int node,
 static int __init process_domain_node(
     struct boot_info *bi, const void *fdt, int dom_node)
 {
-    int node;
+    int node, property;
     struct boot_domain *bd = &bi->domains[bi->nr_domains];
     const char *name = fdt_get_name(fdt, dom_node, NULL) ?: "unknown";
     int address_cells = fdt_address_cells(fdt, dom_node);
     int size_cells = fdt_size_cells(fdt, dom_node);
 
+    fdt_for_each_property_offset(property, fdt, dom_node)
+    {
+        const struct fdt_property *prop;
+        const char *prop_name;
+        int name_len, rc;
+
+        prop = fdt_get_property_by_offset(fdt, property, NULL);
+        if ( !prop )
+            continue; /* silently skip */
+
+        prop_name = fdt_get_string(fdt, fdt32_to_cpu(prop->nameoff), 
&name_len);
+
+        if ( !strncmp(prop_name, "domid", name_len) )
+        {
+            uint32_t val = DOMID_INVALID;
+
+            if ( (rc = fdt_prop_as_u32(prop, &val)) )
+            {
+                printk(XENLOG_ERR
+                       "  failed processing domain id for domain %s\n", name);
+                return rc;
+            }
+            if ( val >= DOMID_FIRST_RESERVED )
+            {
+                printk(XENLOG_ERR "  invalid domain id for domain %s\n", name);
+                return -EINVAL;
+            }
+
+            for ( unsigned int i = 0; i < bi->nr_domains; i++ )
+            {
+                if ( bi->domains[i].domid == val )
+                {
+                    printk(XENLOG_ERR "  duplicate id for domain %s\n", name);
+                    return -EINVAL;
+                }
+            }
+
+            bd->domid = val;
+            printk(XENLOG_INFO "  domid: %d\n", bd->domid);
+        }
+    }
+
     fdt_for_each_subnode(node, fdt, dom_node)
     {
         if ( !fdt_node_check_compatible(fdt, node, "multiboot,kernel") )
@@ -258,6 +301,13 @@ static int __init process_domain_node(
         return -ENODATA;
     }
 
+    if ( bd->domid == DOMID_INVALID )
+        bd->domid = get_initial_domain_id();
+    else if ( bd->domid != get_initial_domain_id() )
+        printk(XENLOG_WARNING
+               "warning: unsupported boot. d%d is not the initial domain.\n",
+               bd->domid);
+
     return 0;
 }
 
-- 
2.43.0