[PATCH v3 12/16] 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>
---
v3:
    * Remove ramdisk parsing
    * Add missing xen/errno.h include
---
 xen/arch/x86/domain-builder/fdt.c   | 39 ++++++++++++++++++++++++++++-
 xen/arch/x86/setup.c                |  5 ++--
 xen/include/xen/libfdt/libfdt-xen.h | 11 ++++++++
 3 files changed, 52 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/domain-builder/fdt.c 
b/xen/arch/x86/domain-builder/fdt.c
index 0f5fd01557..4c6aafe195 100644
--- a/xen/arch/x86/domain-builder/fdt.c
+++ b/xen/arch/x86/domain-builder/fdt.c
@@ -8,6 +8,7 @@
 #include <xen/libfdt/libfdt.h>
 
 #include <asm/bootinfo.h>
+#include <asm/guest.h>
 #include <asm/page.h>
 #include <asm/setup.h>
 
@@ -158,12 +159,42 @@ 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;
+
+        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) == 0 )
+        {
+            uint32_t val = DOMID_INVALID;
+            if ( fdt_prop_as_u32(prop, &val) != 0 )
+            {
+                printk("  failed processing domain id for domain %s\n", name);
+                return -EINVAL;
+            }
+            if ( val >= DOMID_FIRST_RESERVED )
+            {
+                printk("  invalid domain id for domain %s\n", name);
+                return -EINVAL;
+            }
+            bd->domid = (domid_t)val;
+            printk("  domid: %d\n", bd->domid);
+        }
+    }
+
     fdt_for_each_subnode(node, fdt, dom_node)
     {
         if ( fdt_node_check_compatible(fdt, node, "multiboot,kernel") == 0 )
@@ -233,6 +264,12 @@ 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
+               "WARN: Booting without initial domid not supported.\n");
+
     return 0;
 }
 
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 3dfa81b48c..db7280225e 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1033,8 +1033,9 @@ 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);
     if ( IS_ERR(d) )
         panic("Error creating d%u: %ld\n", bd->domid, PTR_ERR(d));
diff --git a/xen/include/xen/libfdt/libfdt-xen.h 
b/xen/include/xen/libfdt/libfdt-xen.h
index e473fbaf0c..3031bec90e 100644
--- a/xen/include/xen/libfdt/libfdt-xen.h
+++ b/xen/include/xen/libfdt/libfdt-xen.h
@@ -12,6 +12,7 @@
 #define LIBFDT_XEN_H
 
 #include <xen/libfdt/libfdt.h>
+#include <xen/errno.h>
 
 static inline int __init fdt_cell_as_u32(const fdt32_t *cell)
 {
@@ -23,6 +24,16 @@ static inline uint64_t  __init fdt_cell_as_u64(const fdt32_t 
*cell)
     return ((uint64_t)fdt32_to_cpu(cell[0]) << 32) | fdt32_to_cpu(cell[1]);
 }
 
+static inline int __init fdt_prop_as_u32(
+    const struct fdt_property *prop, uint32_t *val)
+{
+    if ( !prop || fdt32_to_cpu(prop->len) < sizeof(u32) )
+        return -EINVAL;
+
+    *val = fdt_cell_as_u32((fdt32_t *)prop->data);
+    return 0;
+}
+
 static inline bool __init fdt_get_prop_offset(
     const void *fdt, int node, const char *name, unsigned long *offset)
 {
-- 
2.43.0