[PATCH v6 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>
Reviewed-by: Denis Mukhin <dmukhin@xxxxxxxx>
Reviewed-by: Jason Andryuk <jason.andryuk@xxxxxxx>
---
 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 c8de028439..10ff67ac37 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1043,8 +1043,9 @@ 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 507f383f8e..2c05b0a22d 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 fdt_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 fdt_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: d%u is not the expected initial domain (d%u)\n",
+               bd->domid, get_initial_domain_id());
+
     return 0;
 }
 
-- 
2.43.0