[PATCH v2 07/15] x86/hyperlaunch: initial support for hyperlaunch device tree

["Daniel P. Smith" <dpsmith@xxxxxxxxxxxxxxxxxxxx>]

Add the ability to detect both a formal hyperlaunch device tree or a dom0less
device tree. If the hyperlaunch device tree is found, then count the number of
domain entries, reporting an error if more than one is found.

Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
---
Changes since v1:
- corrected typo in error message
- clarified commit message on "reporting"
- added missing inline decl
- code style
---
 xen/arch/x86/domain-builder/core.c  | 15 +++++++
 xen/arch/x86/domain-builder/fdt.c   | 65 ++++++++++++++++++++++++++++-
 xen/arch/x86/domain-builder/fdt.h   |  5 +++
 xen/arch/x86/include/asm/bootinfo.h |  1 +
 4 files changed, 85 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/domain-builder/core.c 
b/xen/arch/x86/domain-builder/core.c
index d6ae94f45c72..c50eff34fb68 100644
--- a/xen/arch/x86/domain-builder/core.c
+++ b/xen/arch/x86/domain-builder/core.c
@@ -44,6 +44,21 @@ void __init builder_init(struct boot_info *bi)
             break;
         }
     }
+
+    if ( bi->hyperlaunch_enabled )
+    {
+        int ret;
+
+        printk(XENLOG_INFO "Hyperlaunch configuration:\n");
+        if ( (ret = walk_hyperlaunch_fdt(bi)) < 0 )
+        {
+            printk(XENLOG_INFO "  walk of device tree failed (%d)\n", ret);
+            bi->hyperlaunch_enabled = false;
+            return;
+        }
+
+        printk(XENLOG_INFO "  Number of domains: %d\n", bi->nr_domains);
+    }
 }
 
 /*
diff --git a/xen/arch/x86/domain-builder/fdt.c 
b/xen/arch/x86/domain-builder/fdt.c
index 4a3f80648f86..5793bdc9fd47 100644
--- a/xen/arch/x86/domain-builder/fdt.c
+++ b/xen/arch/x86/domain-builder/fdt.c
@@ -13,14 +13,77 @@
 
 #include "fdt.h"
 
+static int __init find_hyperlaunch_node(const void *fdt)
+{
+    int hv_node = fdt_path_offset(fdt, "/chosen/hypervisor");
+
+    if ( hv_node >= 0 )
+    {
+        /* Anything other than zero indicates no match */
+        if ( fdt_node_check_compatible(fdt, hv_node, "hypervisor,xen") )
+            return -ENODATA;
+        else
+            return hv_node;
+    }
+    else
+    {
+        /* Lood for dom0less config */
+        int node, chosen_node = fdt_path_offset(fdt, "/chosen");
+        if ( chosen_node < 0 )
+            return -ENOENT;
+
+        fdt_for_each_subnode(node, fdt, chosen_node)
+        {
+            if ( fdt_node_check_compatible(fdt, node, "xen,domain") == 0 )
+                return chosen_node;
+        }
+    }
+
+    return -ENODATA;
+}
+
 int __init has_hyperlaunch_fdt(struct boot_info *bi)
 {
     int ret = 0;
     const void *fdt = bootstrap_map_bm(&bi->mods[HYPERLAUNCH_MODULE_IDX]);
 
-    if ( fdt_check_header(fdt) < 0 )
+    if ( !fdt || fdt_check_header(fdt) < 0 )
         ret = -EINVAL;
+    else
+        ret = find_hyperlaunch_node(fdt);
+
+    bootstrap_unmap();
+
+    return ret < 0 ? ret : 0;
+}
+
+int __init walk_hyperlaunch_fdt(struct boot_info *bi)
+{
+    int ret = 0, hv_node, node;
+    void *fdt = bootstrap_map_bm(&bi->mods[HYPERLAUNCH_MODULE_IDX]);
+
+    if ( unlikely(!fdt) )
+        return -EINVAL;
+
+    hv_node = find_hyperlaunch_node(fdt);
+    if ( hv_node < 0 )
+    {
+        ret = hv_node;
+        goto err_out;
+    }
+
+    fdt_for_each_subnode(node, fdt, hv_node)
+    {
+        ret = fdt_node_check_compatible(fdt, node, "xen,domain");
+        if ( ret == 0 )
+            bi->nr_domains++;
+    }
+
+    /* Until multi-domain construction is added, throw an error */
+    if ( !bi->nr_domains || bi->nr_domains > 1 )
+        printk(XENLOG_ERR "Hyperlaunch only supports dom0 construction\n");
 
+ err_out:
     bootstrap_unmap();
 
     return ret;
diff --git a/xen/arch/x86/domain-builder/fdt.h 
b/xen/arch/x86/domain-builder/fdt.h
index 1c1569a9c633..f5b89cb54b29 100644
--- a/xen/arch/x86/domain-builder/fdt.h
+++ b/xen/arch/x86/domain-builder/fdt.h
@@ -11,11 +11,16 @@
 
 #ifdef CONFIG_DOMAIN_BUILDER
 int has_hyperlaunch_fdt(struct boot_info *bi);
+int walk_hyperlaunch_fdt(struct boot_info *bi);
 #else
 static inline int __init has_hyperlaunch_fdt(struct boot_info *bi)
 {
     return -EINVAL;
 }
+static inline int __init walk_hyperlaunch_fdt(struct boot_info *bi)
+{
+    return -EINVAL;
+}
 #endif
 
 #endif /* __XEN_X86_FDT_H__ */
diff --git a/xen/arch/x86/include/asm/bootinfo.h 
b/xen/arch/x86/include/asm/bootinfo.h
index 208bec90913d..683ca9dbe2e0 100644
--- a/xen/arch/x86/include/asm/bootinfo.h
+++ b/xen/arch/x86/include/asm/bootinfo.h
@@ -84,6 +84,7 @@ struct boot_info {
     bool hyperlaunch_enabled;
 
     unsigned int nr_modules;
+    unsigned int nr_domains;
     struct boot_module mods[MAX_NR_BOOTMODS + 1];
     struct boot_domain domains[MAX_NR_BOOTDOMS];
 };
-- 
2.30.2